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godot/drivers/etc1/rg_etc1.cpp
Juan Linietsky 0b806ee0fc GODOT IS OPEN SOURCE
2014-02-09 22:10:30 -03:00

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// File: rg_etc1.cpp - Fast, high quality ETC1 block packer/unpacker - Rich Geldreich <richgel99@gmail.com>
// Please see ZLIB license at the end of rg_etc1.h.
//
// For more information Ericsson Texture Compression (ETC/ETC1), see:
// http://www.khronos.org/registry/gles/extensions/OES/OES_compressed_ETC1_RGB8_texture.txt
//
// v1.03 - 5/12/13 - Initial public release
#include "rg_etc1.h"
#include <stdlib.h>
#include <string.h>
#include <assert.h>
//#include <stdio.h>
#include <math.h>
#include <stdio.h>
#pragma warning (disable: 4201) // nonstandard extension used : nameless struct/union
#if defined(_DEBUG) || defined(DEBUG)
#define RG_ETC1_BUILD_DEBUG
#endif
#define RG_ETC1_ASSERT assert
namespace rg_etc1
{
inline int intabs(int val) {
return val<0?-val:val;
}
typedef unsigned char uint8;
typedef unsigned short uint16;
typedef unsigned int uint;
typedef unsigned int uint32;
typedef long long int64;
typedef unsigned long long uint64;
const uint32 cUINT32_MAX = 0xFFFFFFFFU;
const uint64 cUINT64_MAX = 0xFFFFFFFFFFFFFFFFULL; //0xFFFFFFFFFFFFFFFFui64;
template<typename T> inline T minimum(T a, T b) { return (a < b) ? a : b; }
template<typename T> inline T minimum(T a, T b, T c) { return minimum(minimum(a, b), c); }
template<typename T> inline T maximum(T a, T b) { return (a > b) ? a : b; }
template<typename T> inline T maximum(T a, T b, T c) { return maximum(maximum(a, b), c); }
template<typename T> inline T clamp(T value, T low, T high) { return (value < low) ? low : ((value > high) ? high : value); }
template<typename T> inline T square(T value) { return value * value; }
template<typename T> inline void zero_object(T& obj) { memset((void*)&obj, 0, sizeof(obj)); }
template<typename T> inline void zero_this(T* pObj) { memset((void*)pObj, 0, sizeof(*pObj)); }
template<class T, size_t N> T decay_array_to_subtype(T (&a)[N]);
#define RG_ETC1_ARRAY_SIZE(X) (sizeof(X) / sizeof(decay_array_to_subtype(X)))
enum eNoClamp { cNoClamp };
struct color_quad_u8
{
static inline int clamp(int v) { if (v & 0xFFFFFF00U) v = (~(static_cast<int>(v) >> 31)) & 0xFF; return v; }
struct component_traits { enum { cSigned = false, cFloat = false, cMin = 0U, cMax = 255U }; };
public:
typedef unsigned char component_t;
typedef int parameter_t;
enum { cNumComps = 4 };
union
{
struct
{
component_t r;
component_t g;
component_t b;
component_t a;
};
component_t c[cNumComps];
uint32 m_u32;
};
inline color_quad_u8()
{
}
inline color_quad_u8(const color_quad_u8& other) : m_u32(other.m_u32)
{
}
explicit inline color_quad_u8(parameter_t y, parameter_t alpha = component_traits::cMax)
{
set(y, alpha);
}
inline color_quad_u8(parameter_t red, parameter_t green, parameter_t blue, parameter_t alpha = component_traits::cMax)
{
set(red, green, blue, alpha);
}
explicit inline color_quad_u8(eNoClamp, parameter_t y, parameter_t alpha = component_traits::cMax)
{
set_noclamp_y_alpha(y, alpha);
}
inline color_quad_u8(eNoClamp, parameter_t red, parameter_t green, parameter_t blue, parameter_t alpha = component_traits::cMax)
{
set_noclamp_rgba(red, green, blue, alpha);
}
inline void clear()
{
m_u32 = 0;
}
inline color_quad_u8& operator= (const color_quad_u8& other)
{
m_u32 = other.m_u32;
return *this;
}
inline color_quad_u8& set_rgb(const color_quad_u8& other)
{
r = other.r;
g = other.g;
b = other.b;
return *this;
}
inline color_quad_u8& operator= (parameter_t y)
{
set(y, component_traits::cMax);
return *this;
}
inline color_quad_u8& set(parameter_t y, parameter_t alpha = component_traits::cMax)
{
y = clamp(y);
alpha = clamp(alpha);
r = static_cast<component_t>(y);
g = static_cast<component_t>(y);
b = static_cast<component_t>(y);
a = static_cast<component_t>(alpha);
return *this;
}
inline color_quad_u8& set_noclamp_y_alpha(parameter_t y, parameter_t alpha = component_traits::cMax)
{
RG_ETC1_ASSERT( (y >= component_traits::cMin) && (y <= component_traits::cMax) );
RG_ETC1_ASSERT( (alpha >= component_traits::cMin) && (alpha <= component_traits::cMax) );
r = static_cast<component_t>(y);
g = static_cast<component_t>(y);
b = static_cast<component_t>(y);
a = static_cast<component_t>(alpha);
return *this;
}
inline color_quad_u8& set(parameter_t red, parameter_t green, parameter_t blue, parameter_t alpha = component_traits::cMax)
{
r = static_cast<component_t>(clamp(red));
g = static_cast<component_t>(clamp(green));
b = static_cast<component_t>(clamp(blue));
a = static_cast<component_t>(clamp(alpha));
return *this;
}
inline color_quad_u8& set_noclamp_rgba(parameter_t red, parameter_t green, parameter_t blue, parameter_t alpha)
{
RG_ETC1_ASSERT( (red >= component_traits::cMin) && (red <= component_traits::cMax) );
RG_ETC1_ASSERT( (green >= component_traits::cMin) && (green <= component_traits::cMax) );
RG_ETC1_ASSERT( (blue >= component_traits::cMin) && (blue <= component_traits::cMax) );
RG_ETC1_ASSERT( (alpha >= component_traits::cMin) && (alpha <= component_traits::cMax) );
r = static_cast<component_t>(red);
g = static_cast<component_t>(green);
b = static_cast<component_t>(blue);
a = static_cast<component_t>(alpha);
return *this;
}
inline color_quad_u8& set_noclamp_rgb(parameter_t red, parameter_t green, parameter_t blue)
{
RG_ETC1_ASSERT( (red >= component_traits::cMin) && (red <= component_traits::cMax) );
RG_ETC1_ASSERT( (green >= component_traits::cMin) && (green <= component_traits::cMax) );
RG_ETC1_ASSERT( (blue >= component_traits::cMin) && (blue <= component_traits::cMax) );
r = static_cast<component_t>(red);
g = static_cast<component_t>(green);
b = static_cast<component_t>(blue);
return *this;
}
static inline parameter_t get_min_comp() { return component_traits::cMin; }
static inline parameter_t get_max_comp() { return component_traits::cMax; }
static inline bool get_comps_are_signed() { return component_traits::cSigned; }
inline component_t operator[] (uint i) const { RG_ETC1_ASSERT(i < cNumComps); return c[i]; }
inline component_t& operator[] (uint i) { RG_ETC1_ASSERT(i < cNumComps); return c[i]; }
inline color_quad_u8& set_component(uint i, parameter_t f)
{
RG_ETC1_ASSERT(i < cNumComps);
c[i] = static_cast<component_t>(clamp(f));
return *this;
}
inline color_quad_u8& set_grayscale(parameter_t l)
{
component_t x = static_cast<component_t>(clamp(l));
c[0] = x;
c[1] = x;
c[2] = x;
return *this;
}
inline color_quad_u8& clamp(const color_quad_u8& l, const color_quad_u8& h)
{
for (uint i = 0; i < cNumComps; i++)
c[i] = static_cast<component_t>(rg_etc1::clamp<parameter_t>(c[i], l[i], h[i]));
return *this;
}
inline color_quad_u8& clamp(parameter_t l, parameter_t h)
{
for (uint i = 0; i < cNumComps; i++)
c[i] = static_cast<component_t>(rg_etc1::clamp<parameter_t>(c[i], l, h));
return *this;
}
// Returns CCIR 601 luma (consistent with color_utils::RGB_To_Y).
inline parameter_t get_luma() const
{
return static_cast<parameter_t>((19595U * r + 38470U * g + 7471U * b + 32768U) >> 16U);
}
// Returns REC 709 luma.
inline parameter_t get_luma_rec709() const
{
return static_cast<parameter_t>((13938U * r + 46869U * g + 4729U * b + 32768U) >> 16U);
}
inline uint squared_distance_rgb(const color_quad_u8& c) const
{
return rg_etc1::square(r - c.r) + rg_etc1::square(g - c.g) + rg_etc1::square(b - c.b);
}
inline uint squared_distance_rgba(const color_quad_u8& c) const
{
return rg_etc1::square(r - c.r) + rg_etc1::square(g - c.g) + rg_etc1::square(b - c.b) + rg_etc1::square(a - c.a);
}
inline bool rgb_equals(const color_quad_u8& rhs) const
{
return (r == rhs.r) && (g == rhs.g) && (b == rhs.b);
}
inline bool operator== (const color_quad_u8& rhs) const
{
return m_u32 == rhs.m_u32;
}
color_quad_u8& operator+= (const color_quad_u8& other)
{
for (uint i = 0; i < 4; i++)
c[i] = static_cast<component_t>(clamp(c[i] + other.c[i]));
return *this;
}
color_quad_u8& operator-= (const color_quad_u8& other)
{
for (uint i = 0; i < 4; i++)
c[i] = static_cast<component_t>(clamp(c[i] - other.c[i]));
return *this;
}
friend color_quad_u8 operator+ (const color_quad_u8& lhs, const color_quad_u8& rhs)
{
color_quad_u8 result(lhs);
result += rhs;
return result;
}
friend color_quad_u8 operator- (const color_quad_u8& lhs, const color_quad_u8& rhs)
{
color_quad_u8 result(lhs);
result -= rhs;
return result;
}
}; // class color_quad_u8
struct vec3F
{
float m_s[3];
inline vec3F() { }
inline vec3F(float s) { m_s[0] = s; m_s[1] = s; m_s[2] = s; }
inline vec3F(float x, float y, float z) { m_s[0] = x; m_s[1] = y; m_s[2] = z; }
inline float operator[] (uint i) const { RG_ETC1_ASSERT(i < 3); return m_s[i]; }
inline vec3F& operator += (const vec3F& other) { for (uint i = 0; i < 3; i++) m_s[i] += other.m_s[i]; return *this; }
inline vec3F& operator *= (float s) { for (uint i = 0; i < 3; i++) m_s[i] *= s; return *this; }
};
enum etc_constants
{
cETC1BytesPerBlock = 8U,
cETC1SelectorBits = 2U,
cETC1SelectorValues = 1U << cETC1SelectorBits,
cETC1SelectorMask = cETC1SelectorValues - 1U,
cETC1BlockShift = 2U,
cETC1BlockSize = 1U << cETC1BlockShift,
cETC1LSBSelectorIndicesBitOffset = 0,
cETC1MSBSelectorIndicesBitOffset = 16,
cETC1FlipBitOffset = 32,
cETC1DiffBitOffset = 33,
cETC1IntenModifierNumBits = 3,
cETC1IntenModifierValues = 1 << cETC1IntenModifierNumBits,
cETC1RightIntenModifierTableBitOffset = 34,
cETC1LeftIntenModifierTableBitOffset = 37,
// Base+Delta encoding (5 bit bases, 3 bit delta)
cETC1BaseColorCompNumBits = 5,
cETC1BaseColorCompMax = 1 << cETC1BaseColorCompNumBits,
cETC1DeltaColorCompNumBits = 3,
cETC1DeltaColorComp = 1 << cETC1DeltaColorCompNumBits,
cETC1DeltaColorCompMax = 1 << cETC1DeltaColorCompNumBits,
cETC1BaseColor5RBitOffset = 59,
cETC1BaseColor5GBitOffset = 51,
cETC1BaseColor5BBitOffset = 43,
cETC1DeltaColor3RBitOffset = 56,
cETC1DeltaColor3GBitOffset = 48,
cETC1DeltaColor3BBitOffset = 40,
// Absolute (non-delta) encoding (two 4-bit per component bases)
cETC1AbsColorCompNumBits = 4,
cETC1AbsColorCompMax = 1 << cETC1AbsColorCompNumBits,
cETC1AbsColor4R1BitOffset = 60,
cETC1AbsColor4G1BitOffset = 52,
cETC1AbsColor4B1BitOffset = 44,
cETC1AbsColor4R2BitOffset = 56,
cETC1AbsColor4G2BitOffset = 48,
cETC1AbsColor4B2BitOffset = 40,
cETC1ColorDeltaMin = -4,
cETC1ColorDeltaMax = 3,
// Delta3:
// 0 1 2 3 4 5 6 7
// 000 001 010 011 100 101 110 111
// 0 1 2 3 -4 -3 -2 -1
};
static uint8 g_quant5_tab[256+16];
static const int g_etc1_inten_tables[cETC1IntenModifierValues][cETC1SelectorValues] =
{
{ -8, -2, 2, 8 }, { -17, -5, 5, 17 }, { -29, -9, 9, 29 }, { -42, -13, 13, 42 },
{ -60, -18, 18, 60 }, { -80, -24, 24, 80 }, { -106, -33, 33, 106 }, { -183, -47, 47, 183 }
};
static const uint8 g_etc1_to_selector_index[cETC1SelectorValues] = { 2, 3, 1, 0 };
static const uint8 g_selector_index_to_etc1[cETC1SelectorValues] = { 3, 2, 0, 1 };
// Given an ETC1 diff/inten_table/selector, and an 8-bit desired color, this table encodes the best packed_color in the low byte, and the abs error in the high byte.
static uint16 g_etc1_inverse_lookup[2*8*4][256]; // [diff/inten_table/selector][desired_color]
// g_color8_to_etc_block_config[color][table_index] = Supplies for each 8-bit color value a list of packed ETC1 diff/intensity table/selectors/packed_colors that map to that color.
// To pack: diff | (inten << 1) | (selector << 4) | (packed_c << 8)
static const uint16 g_color8_to_etc_block_config_0_255[2][33] =
{
{ 0x0000, 0x0010, 0x0002, 0x0012, 0x0004, 0x0014, 0x0006, 0x0016, 0x0008, 0x0018, 0x000A, 0x001A, 0x000C, 0x001C, 0x000E, 0x001E,
0x0001, 0x0011, 0x0003, 0x0013, 0x0005, 0x0015, 0x0007, 0x0017, 0x0009, 0x0019, 0x000B, 0x001B, 0x000D, 0x001D, 0x000F, 0x001F, 0xFFFF },
{ 0x0F20, 0x0F30, 0x0E32, 0x0F22, 0x0E34, 0x0F24, 0x0D36, 0x0F26, 0x0C38, 0x0E28, 0x0B3A, 0x0E2A, 0x093C, 0x0E2C, 0x053E, 0x0D2E,
0x1E31, 0x1F21, 0x1D33, 0x1F23, 0x1C35, 0x1E25, 0x1A37, 0x1E27, 0x1839, 0x1D29, 0x163B, 0x1C2B, 0x133D, 0x1B2D, 0x093F, 0x1A2F, 0xFFFF },
};
// Really only [254][11].
static const uint16 g_color8_to_etc_block_config_1_to_254[254][12] =
{
{ 0x021C, 0x0D0D, 0xFFFF }, { 0x0020, 0x0021, 0x0A0B, 0x061F, 0xFFFF }, { 0x0113, 0x0217, 0xFFFF }, { 0x0116, 0x031E,
0x0B0E, 0x0405, 0xFFFF }, { 0x0022, 0x0204, 0x050A, 0x0023, 0xFFFF }, { 0x0111, 0x0319, 0x0809, 0x170F, 0xFFFF }, {
0x0303, 0x0215, 0x0607, 0xFFFF }, { 0x0030, 0x0114, 0x0408, 0x0031, 0x0201, 0x051D, 0xFFFF }, { 0x0100, 0x0024, 0x0306,
0x0025, 0x041B, 0x0E0D, 0xFFFF }, { 0x021A, 0x0121, 0x0B0B, 0x071F, 0xFFFF }, { 0x0213, 0x0317, 0xFFFF }, { 0x0112,
0x0505, 0xFFFF }, { 0x0026, 0x070C, 0x0123, 0x0027, 0xFFFF }, { 0x0211, 0x0909, 0xFFFF }, { 0x0110, 0x0315, 0x0707,
0x0419, 0x180F, 0xFFFF }, { 0x0218, 0x0131, 0x0301, 0x0403, 0x061D, 0xFFFF }, { 0x0032, 0x0202, 0x0033, 0x0125, 0x051B,
0x0F0D, 0xFFFF }, { 0x0028, 0x031C, 0x0221, 0x0029, 0xFFFF }, { 0x0120, 0x0313, 0x0C0B, 0x081F, 0xFFFF }, { 0x0605,
0x0417, 0xFFFF }, { 0x0216, 0x041E, 0x0C0E, 0x0223, 0x0127, 0xFFFF }, { 0x0122, 0x0304, 0x060A, 0x0311, 0x0A09, 0xFFFF
}, { 0x0519, 0x190F, 0xFFFF }, { 0x002A, 0x0231, 0x0503, 0x0415, 0x0807, 0x002B, 0x071D, 0xFFFF }, { 0x0130, 0x0214,
0x0508, 0x0401, 0x0133, 0x0225, 0x061B, 0xFFFF }, { 0x0200, 0x0124, 0x0406, 0x0321, 0x0129, 0x100D, 0xFFFF }, { 0x031A,
0x0D0B, 0x091F, 0xFFFF }, { 0x0413, 0x0705, 0x0517, 0xFFFF }, { 0x0212, 0x0034, 0x0323, 0x0035, 0x0227, 0xFFFF }, {
0x0126, 0x080C, 0x0B09, 0xFFFF }, { 0x0411, 0x0619, 0x1A0F, 0xFFFF }, { 0x0210, 0x0331, 0x0603, 0x0515, 0x0907, 0x012B,
0xFFFF }, { 0x0318, 0x002C, 0x0501, 0x0233, 0x0325, 0x071B, 0x002D, 0x081D, 0xFFFF }, { 0x0132, 0x0302, 0x0229, 0x110D,
0xFFFF }, { 0x0128, 0x041C, 0x0421, 0x0E0B, 0x0A1F, 0xFFFF }, { 0x0220, 0x0513, 0x0617, 0xFFFF }, { 0x0135, 0x0805,
0x0327, 0xFFFF }, { 0x0316, 0x051E, 0x0D0E, 0x0423, 0xFFFF }, { 0x0222, 0x0404, 0x070A, 0x0511, 0x0719, 0x0C09, 0x1B0F,
0xFFFF }, { 0x0703, 0x0615, 0x0A07, 0x022B, 0xFFFF }, { 0x012A, 0x0431, 0x0601, 0x0333, 0x012D, 0x091D, 0xFFFF }, {
0x0230, 0x0314, 0x0036, 0x0608, 0x0425, 0x0037, 0x0329, 0x081B, 0x120D, 0xFFFF }, { 0x0300, 0x0224, 0x0506, 0x0521,
0x0F0B, 0x0B1F, 0xFFFF }, { 0x041A, 0x0613, 0x0717, 0xFFFF }, { 0x0235, 0x0905, 0xFFFF }, { 0x0312, 0x0134, 0x0523,
0x0427, 0xFFFF }, { 0x0226, 0x090C, 0x002E, 0x0611, 0x0D09, 0x002F, 0xFFFF }, { 0x0715, 0x0B07, 0x0819, 0x032B, 0x1C0F,
0xFFFF }, { 0x0310, 0x0531, 0x0701, 0x0803, 0x022D, 0x0A1D, 0xFFFF }, { 0x0418, 0x012C, 0x0433, 0x0525, 0x0137, 0x091B,
0x130D, 0xFFFF }, { 0x0232, 0x0402, 0x0621, 0x0429, 0xFFFF }, { 0x0228, 0x051C, 0x0713, 0x100B, 0x0C1F, 0xFFFF }, {
0x0320, 0x0335, 0x0A05, 0x0817, 0xFFFF }, { 0x0623, 0x0527, 0xFFFF }, { 0x0416, 0x061E, 0x0E0E, 0x0711, 0x0E09, 0x012F,
0xFFFF }, { 0x0322, 0x0504, 0x080A, 0x0919, 0x1D0F, 0xFFFF }, { 0x0631, 0x0903, 0x0815, 0x0C07, 0x042B, 0x032D, 0x0B1D,
0xFFFF }, { 0x022A, 0x0801, 0x0533, 0x0625, 0x0237, 0x0A1B, 0xFFFF }, { 0x0330, 0x0414, 0x0136, 0x0708, 0x0721, 0x0529,
0x140D, 0xFFFF }, { 0x0400, 0x0324, 0x0606, 0x0038, 0x0039, 0x110B, 0x0D1F, 0xFFFF }, { 0x051A, 0x0813, 0x0B05, 0x0917,
0xFFFF }, { 0x0723, 0x0435, 0x0627, 0xFFFF }, { 0x0412, 0x0234, 0x0F09, 0x022F, 0xFFFF }, { 0x0326, 0x0A0C, 0x012E,
0x0811, 0x0A19, 0x1E0F, 0xFFFF }, { 0x0731, 0x0A03, 0x0915, 0x0D07, 0x052B, 0xFFFF }, { 0x0410, 0x0901, 0x0633, 0x0725,
0x0337, 0x0B1B, 0x042D, 0x0C1D, 0xFFFF }, { 0x0518, 0x022C, 0x0629, 0x150D, 0xFFFF }, { 0x0332, 0x0502, 0x0821, 0x0139,
0x120B, 0x0E1F, 0xFFFF }, { 0x0328, 0x061C, 0x0913, 0x0A17, 0xFFFF }, { 0x0420, 0x0535, 0x0C05, 0x0727, 0xFFFF }, {
0x0823, 0x032F, 0xFFFF }, { 0x0516, 0x071E, 0x0F0E, 0x0911, 0x0B19, 0x1009, 0x1F0F, 0xFFFF }, { 0x0422, 0x0604, 0x090A,
0x0B03, 0x0A15, 0x0E07, 0x062B, 0xFFFF }, { 0x0831, 0x0A01, 0x0733, 0x052D, 0x0D1D, 0xFFFF }, { 0x032A, 0x0825, 0x0437,
0x0729, 0x0C1B, 0x160D, 0xFFFF }, { 0x0430, 0x0514, 0x0236, 0x0808, 0x0921, 0x0239, 0x130B, 0x0F1F, 0xFFFF }, { 0x0500,
0x0424, 0x0706, 0x0138, 0x0A13, 0x0B17, 0xFFFF }, { 0x061A, 0x0635, 0x0D05, 0xFFFF }, { 0x0923, 0x0827, 0xFFFF }, {
0x0512, 0x0334, 0x003A, 0x0A11, 0x1109, 0x003B, 0x042F, 0xFFFF }, { 0x0426, 0x0B0C, 0x022E, 0x0B15, 0x0F07, 0x0C19,
0x072B, 0xFFFF }, { 0x0931, 0x0B01, 0x0C03, 0x062D, 0x0E1D, 0xFFFF }, { 0x0510, 0x0833, 0x0925, 0x0537, 0x0D1B, 0x170D,
0xFFFF }, { 0x0618, 0x032C, 0x0A21, 0x0339, 0x0829, 0xFFFF }, { 0x0432, 0x0602, 0x0B13, 0x140B, 0x101F, 0xFFFF }, {
0x0428, 0x071C, 0x0735, 0x0E05, 0x0C17, 0xFFFF }, { 0x0520, 0x0A23, 0x0927, 0xFFFF }, { 0x0B11, 0x1209, 0x013B, 0x052F,
0xFFFF }, { 0x0616, 0x081E, 0x0D19, 0xFFFF }, { 0x0522, 0x0704, 0x0A0A, 0x0A31, 0x0D03, 0x0C15, 0x1007, 0x082B, 0x072D,
0x0F1D, 0xFFFF }, { 0x0C01, 0x0933, 0x0A25, 0x0637, 0x0E1B, 0xFFFF }, { 0x042A, 0x0B21, 0x0929, 0x180D, 0xFFFF }, {
0x0530, 0x0614, 0x0336, 0x0908, 0x0439, 0x150B, 0x111F, 0xFFFF }, { 0x0600, 0x0524, 0x0806, 0x0238, 0x0C13, 0x0F05,
0x0D17, 0xFFFF }, { 0x071A, 0x0B23, 0x0835, 0x0A27, 0xFFFF }, { 0x1309, 0x023B, 0x062F, 0xFFFF }, { 0x0612, 0x0434,
0x013A, 0x0C11, 0x0E19, 0xFFFF }, { 0x0526, 0x0C0C, 0x032E, 0x0B31, 0x0E03, 0x0D15, 0x1107, 0x092B, 0xFFFF }, { 0x0D01,
0x0A33, 0x0B25, 0x0737, 0x0F1B, 0x082D, 0x101D, 0xFFFF }, { 0x0610, 0x0A29, 0x190D, 0xFFFF }, { 0x0718, 0x042C, 0x0C21,
0x0539, 0x160B, 0x121F, 0xFFFF }, { 0x0532, 0x0702, 0x0D13, 0x0E17, 0xFFFF }, { 0x0528, 0x081C, 0x0935, 0x1005, 0x0B27,
0xFFFF }, { 0x0620, 0x0C23, 0x033B, 0x072F, 0xFFFF }, { 0x0D11, 0x0F19, 0x1409, 0xFFFF }, { 0x0716, 0x003C, 0x091E,
0x0F03, 0x0E15, 0x1207, 0x0A2B, 0x003D, 0xFFFF }, { 0x0622, 0x0804, 0x0B0A, 0x0C31, 0x0E01, 0x0B33, 0x092D, 0x111D,
0xFFFF }, { 0x0C25, 0x0837, 0x0B29, 0x101B, 0x1A0D, 0xFFFF }, { 0x052A, 0x0D21, 0x0639, 0x170B, 0x131F, 0xFFFF }, {
0x0630, 0x0714, 0x0436, 0x0A08, 0x0E13, 0x0F17, 0xFFFF }, { 0x0700, 0x0624, 0x0906, 0x0338, 0x0A35, 0x1105, 0xFFFF }, {
0x081A, 0x0D23, 0x0C27, 0xFFFF }, { 0x0E11, 0x1509, 0x043B, 0x082F, 0xFFFF }, { 0x0712, 0x0534, 0x023A, 0x0F15, 0x1307,
0x1019, 0x0B2B, 0x013D, 0xFFFF }, { 0x0626, 0x0D0C, 0x042E, 0x0D31, 0x0F01, 0x1003, 0x0A2D, 0x121D, 0xFFFF }, { 0x0C33,
0x0D25, 0x0937, 0x111B, 0x1B0D, 0xFFFF }, { 0x0710, 0x0E21, 0x0739, 0x0C29, 0xFFFF }, { 0x0818, 0x052C, 0x0F13, 0x180B,
0x141F, 0xFFFF }, { 0x0632, 0x0802, 0x0B35, 0x1205, 0x1017, 0xFFFF }, { 0x0628, 0x091C, 0x0E23, 0x0D27, 0xFFFF }, {
0x0720, 0x0F11, 0x1609, 0x053B, 0x092F, 0xFFFF }, { 0x1119, 0x023D, 0xFFFF }, { 0x0816, 0x013C, 0x0A1E, 0x0E31, 0x1103,
0x1015, 0x1407, 0x0C2B, 0x0B2D, 0x131D, 0xFFFF }, { 0x0722, 0x0904, 0x0C0A, 0x1001, 0x0D33, 0x0E25, 0x0A37, 0x121B,
0xFFFF }, { 0x0F21, 0x0D29, 0x1C0D, 0xFFFF }, { 0x062A, 0x0839, 0x190B, 0x151F, 0xFFFF }, { 0x0730, 0x0814, 0x0536,
0x0B08, 0x1013, 0x1305, 0x1117, 0xFFFF }, { 0x0800, 0x0724, 0x0A06, 0x0438, 0x0F23, 0x0C35, 0x0E27, 0xFFFF }, { 0x091A,
0x1709, 0x063B, 0x0A2F, 0xFFFF }, { 0x1011, 0x1219, 0x033D, 0xFFFF }, { 0x0812, 0x0634, 0x033A, 0x0F31, 0x1203, 0x1115,
0x1507, 0x0D2B, 0xFFFF }, { 0x0726, 0x0E0C, 0x052E, 0x1101, 0x0E33, 0x0F25, 0x0B37, 0x131B, 0x0C2D, 0x141D, 0xFFFF }, {
0x0E29, 0x1D0D, 0xFFFF }, { 0x0810, 0x1021, 0x0939, 0x1A0B, 0x161F, 0xFFFF }, { 0x0918, 0x062C, 0x1113, 0x1217, 0xFFFF
}, { 0x0732, 0x0902, 0x0D35, 0x1405, 0x0F27, 0xFFFF }, { 0x0728, 0x0A1C, 0x1023, 0x073B, 0x0B2F, 0xFFFF }, { 0x0820,
0x1111, 0x1319, 0x1809, 0xFFFF }, { 0x1303, 0x1215, 0x1607, 0x0E2B, 0x043D, 0xFFFF }, { 0x0916, 0x023C, 0x0B1E, 0x1031,
0x1201, 0x0F33, 0x0D2D, 0x151D, 0xFFFF }, { 0x0822, 0x0A04, 0x0D0A, 0x1025, 0x0C37, 0x0F29, 0x141B, 0x1E0D, 0xFFFF }, {
0x1121, 0x0A39, 0x1B0B, 0x171F, 0xFFFF }, { 0x072A, 0x1213, 0x1317, 0xFFFF }, { 0x0830, 0x0914, 0x0636, 0x0C08, 0x0E35,
0x1505, 0xFFFF }, { 0x0900, 0x0824, 0x0B06, 0x0538, 0x1123, 0x1027, 0xFFFF }, { 0x0A1A, 0x1211, 0x1909, 0x083B, 0x0C2F,
0xFFFF }, { 0x1315, 0x1707, 0x1419, 0x0F2B, 0x053D, 0xFFFF }, { 0x0912, 0x0734, 0x043A, 0x1131, 0x1301, 0x1403, 0x0E2D,
0x161D, 0xFFFF }, { 0x0826, 0x0F0C, 0x062E, 0x1033, 0x1125, 0x0D37, 0x151B, 0x1F0D, 0xFFFF }, { 0x1221, 0x0B39, 0x1029,
0xFFFF }, { 0x0910, 0x1313, 0x1C0B, 0x181F, 0xFFFF }, { 0x0A18, 0x072C, 0x0F35, 0x1605, 0x1417, 0xFFFF }, { 0x0832,
0x0A02, 0x1223, 0x1127, 0xFFFF }, { 0x0828, 0x0B1C, 0x1311, 0x1A09, 0x093B, 0x0D2F, 0xFFFF }, { 0x0920, 0x1519, 0x063D,
0xFFFF }, { 0x1231, 0x1503, 0x1415, 0x1807, 0x102B, 0x0F2D, 0x171D, 0xFFFF }, { 0x0A16, 0x033C, 0x0C1E, 0x1401, 0x1133,
0x1225, 0x0E37, 0x161B, 0xFFFF }, { 0x0922, 0x0B04, 0x0E0A, 0x1321, 0x1129, 0xFFFF }, { 0x0C39, 0x1D0B, 0x191F, 0xFFFF
}, { 0x082A, 0x1413, 0x1705, 0x1517, 0xFFFF }, { 0x0930, 0x0A14, 0x0736, 0x0D08, 0x1323, 0x1035, 0x1227, 0xFFFF }, {
0x0A00, 0x0924, 0x0C06, 0x0638, 0x1B09, 0x0A3B, 0x0E2F, 0xFFFF }, { 0x0B1A, 0x1411, 0x1619, 0x073D, 0xFFFF }, { 0x1331,
0x1603, 0x1515, 0x1907, 0x112B, 0xFFFF }, { 0x0A12, 0x0834, 0x053A, 0x1501, 0x1233, 0x1325, 0x0F37, 0x171B, 0x102D,
0x181D, 0xFFFF }, { 0x0926, 0x072E, 0x1229, 0xFFFF }, { 0x1421, 0x0D39, 0x1E0B, 0x1A1F, 0xFFFF }, { 0x0A10, 0x1513,
0x1617, 0xFFFF }, { 0x0B18, 0x082C, 0x1135, 0x1805, 0x1327, 0xFFFF }, { 0x0932, 0x0B02, 0x1423, 0x0B3B, 0x0F2F, 0xFFFF
}, { 0x0928, 0x0C1C, 0x1511, 0x1719, 0x1C09, 0xFFFF }, { 0x0A20, 0x1703, 0x1615, 0x1A07, 0x122B, 0x083D, 0xFFFF }, {
0x1431, 0x1601, 0x1333, 0x112D, 0x191D, 0xFFFF }, { 0x0B16, 0x043C, 0x0D1E, 0x1425, 0x1037, 0x1329, 0x181B, 0xFFFF }, {
0x0A22, 0x0C04, 0x0F0A, 0x1521, 0x0E39, 0x1F0B, 0x1B1F, 0xFFFF }, { 0x1613, 0x1717, 0xFFFF }, { 0x092A, 0x1235, 0x1905,
0xFFFF }, { 0x0A30, 0x0B14, 0x0836, 0x0E08, 0x1523, 0x1427, 0xFFFF }, { 0x0B00, 0x0A24, 0x0D06, 0x0738, 0x1611, 0x1D09,
0x0C3B, 0x102F, 0xFFFF }, { 0x0C1A, 0x1715, 0x1B07, 0x1819, 0x132B, 0x093D, 0xFFFF }, { 0x1531, 0x1701, 0x1803, 0x122D,
0x1A1D, 0xFFFF }, { 0x0B12, 0x0934, 0x063A, 0x1433, 0x1525, 0x1137, 0x191B, 0xFFFF }, { 0x0A26, 0x003E, 0x082E, 0x1621,
0x0F39, 0x1429, 0x003F, 0xFFFF }, { 0x1713, 0x1C1F, 0xFFFF }, { 0x0B10, 0x1335, 0x1A05, 0x1817, 0xFFFF }, { 0x0C18,
0x092C, 0x1623, 0x1527, 0xFFFF }, { 0x0A32, 0x0C02, 0x1711, 0x1E09, 0x0D3B, 0x112F, 0xFFFF }, { 0x0A28, 0x0D1C, 0x1919,
0x0A3D, 0xFFFF }, { 0x0B20, 0x1631, 0x1903, 0x1815, 0x1C07, 0x142B, 0x132D, 0x1B1D, 0xFFFF }, { 0x1801, 0x1533, 0x1625,
0x1237, 0x1A1B, 0xFFFF }, { 0x0C16, 0x053C, 0x0E1E, 0x1721, 0x1529, 0x013F, 0xFFFF }, { 0x0B22, 0x0D04, 0x1039, 0x1D1F,
0xFFFF }, { 0x1813, 0x1B05, 0x1917, 0xFFFF }, { 0x0A2A, 0x1723, 0x1435, 0x1627, 0xFFFF }, { 0x0B30, 0x0C14, 0x0936,
0x0F08, 0x1F09, 0x0E3B, 0x122F, 0xFFFF }, { 0x0C00, 0x0B24, 0x0E06, 0x0838, 0x1811, 0x1A19, 0x0B3D, 0xFFFF }, { 0x0D1A,
0x1731, 0x1A03, 0x1915, 0x1D07, 0x152B, 0xFFFF }, { 0x1901, 0x1633, 0x1725, 0x1337, 0x1B1B, 0x142D, 0x1C1D, 0xFFFF }, {
0x0C12, 0x0A34, 0x073A, 0x1629, 0x023F, 0xFFFF }, { 0x0B26, 0x013E, 0x092E, 0x1821, 0x1139, 0x1E1F, 0xFFFF }, { 0x1913,
0x1A17, 0xFFFF }, { 0x0C10, 0x1535, 0x1C05, 0x1727, 0xFFFF }, { 0x0D18, 0x0A2C, 0x1823, 0x0F3B, 0x132F, 0xFFFF }, {
0x0B32, 0x0D02, 0x1911, 0x1B19, 0xFFFF }, { 0x0B28, 0x0E1C, 0x1B03, 0x1A15, 0x1E07, 0x162B, 0x0C3D, 0xFFFF }, { 0x0C20,
0x1831, 0x1A01, 0x1733, 0x152D, 0x1D1D, 0xFFFF }, { 0x1825, 0x1437, 0x1729, 0x1C1B, 0x033F, 0xFFFF }, { 0x0D16, 0x063C,
0x0F1E, 0x1921, 0x1239, 0x1F1F, 0xFFFF }, { 0x0C22, 0x0E04, 0x1A13, 0x1B17, 0xFFFF }, { 0x1635, 0x1D05, 0xFFFF }, {
0x0B2A, 0x1923, 0x1827, 0xFFFF }, { 0x0C30, 0x0D14, 0x0A36, 0x1A11, 0x103B, 0x142F, 0xFFFF }, { 0x0D00, 0x0C24, 0x0F06,
0x0938, 0x1B15, 0x1F07, 0x1C19, 0x172B, 0x0D3D, 0xFFFF }, { 0x0E1A, 0x1931, 0x1B01, 0x1C03, 0x162D, 0x1E1D, 0xFFFF }, {
0x1833, 0x1925, 0x1537, 0x1D1B, 0xFFFF }, { 0x0D12, 0x0B34, 0x083A, 0x1A21, 0x1339, 0x1829, 0x043F, 0xFFFF }, { 0x0C26,
0x023E, 0x0A2E, 0x1B13, 0xFFFF }, { 0x1735, 0x1E05, 0x1C17, 0xFFFF }, { 0x0D10, 0x1A23, 0x1927, 0xFFFF }, { 0x0E18,
0x0B2C, 0x1B11, 0x113B, 0x152F, 0xFFFF }, { 0x0C32, 0x0E02, 0x1D19, 0x0E3D, 0xFFFF }, { 0x0C28, 0x0F1C, 0x1A31, 0x1D03,
0x1C15, 0x182B, 0x172D, 0x1F1D, 0xFFFF }, { 0x0D20, 0x1C01, 0x1933, 0x1A25, 0x1637, 0x1E1B, 0xFFFF }, { 0x1B21, 0x1929,
0x053F, 0xFFFF }, { 0x0E16, 0x073C, 0x1439, 0xFFFF }, { 0x0D22, 0x0F04, 0x1C13, 0x1F05, 0x1D17, 0xFFFF }, { 0x1B23,
0x1835, 0x1A27, 0xFFFF }, { 0x0C2A, 0x123B, 0x162F, 0xFFFF }, { 0x0D30, 0x0E14, 0x0B36, 0x1C11, 0x1E19, 0x0F3D, 0xFFFF
}, { 0x0E00, 0x0D24, 0x0A38, 0x1B31, 0x1E03, 0x1D15, 0x192B, 0xFFFF }, { 0x0F1A, 0x1D01, 0x1A33, 0x1B25, 0x1737, 0x1F1B,
0x182D, 0xFFFF }, { 0x1A29, 0x063F, 0xFFFF }, { 0x0E12, 0x0C34, 0x093A, 0x1C21, 0x1539, 0xFFFF }, { 0x0D26, 0x033E,
0x0B2E, 0x1D13, 0x1E17, 0xFFFF }, { 0x1935, 0x1B27, 0xFFFF }, { 0x0E10, 0x1C23, 0x133B, 0x172F, 0xFFFF }, { 0x0F18,
0x0C2C, 0x1D11, 0x1F19, 0xFFFF }, { 0x0D32, 0x0F02, 0x1F03, 0x1E15, 0x1A2B, 0x103D, 0xFFFF }, { 0x0D28, 0x1C31, 0x1E01,
0x1B33, 0x192D, 0xFFFF }, { 0x0E20, 0x1C25, 0x1837, 0x1B29, 0x073F, 0xFFFF }, { 0x1D21, 0x1639, 0xFFFF }, { 0x0F16,
0x083C, 0x1E13, 0x1F17, 0xFFFF }, { 0x0E22, 0x1A35, 0xFFFF }, { 0x1D23, 0x1C27, 0xFFFF }, { 0x0D2A, 0x1E11, 0x143B,
0x182F, 0xFFFF }, { 0x0E30, 0x0F14, 0x0C36, 0x1F15, 0x1B2B, 0x113D, 0xFFFF }, { 0x0F00, 0x0E24, 0x0B38, 0x1D31, 0x1F01,
0x1A2D, 0xFFFF }, { 0x1C33, 0x1D25, 0x1937, 0xFFFF }, { 0x1E21, 0x1739, 0x1C29, 0x083F, 0xFFFF }, { 0x0F12, 0x0D34,
0x0A3A, 0x1F13, 0xFFFF }, { 0x0E26, 0x043E, 0x0C2E, 0x1B35, 0xFFFF }, { 0x1E23, 0x1D27, 0xFFFF }, { 0x0F10, 0x1F11,
0x153B, 0x192F, 0xFFFF }, { 0x0D2C, 0x123D, 0xFFFF },
};
struct etc1_block
{
// big endian uint64:
// bit ofs: 56 48 40 32 24 16 8 0
// byte ofs: b0, b1, b2, b3, b4, b5, b6, b7
union
{
uint64 m_uint64;
uint8 m_bytes[8];
};
uint8 m_low_color[2];
uint8 m_high_color[2];
enum { cNumSelectorBytes = 4 };
uint8 m_selectors[cNumSelectorBytes];
inline void clear()
{
zero_this(this);
}
inline uint get_byte_bits(uint ofs, uint num) const
{
RG_ETC1_ASSERT((ofs + num) <= 64U);
RG_ETC1_ASSERT(num && (num <= 8U));
RG_ETC1_ASSERT((ofs >> 3) == ((ofs + num - 1) >> 3));
const uint byte_ofs = 7 - (ofs >> 3);
const uint byte_bit_ofs = ofs & 7;
return (m_bytes[byte_ofs] >> byte_bit_ofs) & ((1 << num) - 1);
}
inline void set_byte_bits(uint ofs, uint num, uint bits)
{
RG_ETC1_ASSERT((ofs + num) <= 64U);
RG_ETC1_ASSERT(num && (num < 32U));
RG_ETC1_ASSERT((ofs >> 3) == ((ofs + num - 1) >> 3));
RG_ETC1_ASSERT(bits < (1U << num));
const uint byte_ofs = 7 - (ofs >> 3);
const uint byte_bit_ofs = ofs & 7;
const uint mask = (1 << num) - 1;
m_bytes[byte_ofs] &= ~(mask << byte_bit_ofs);
m_bytes[byte_ofs] |= (bits << byte_bit_ofs);
}
// false = left/right subblocks
// true = upper/lower subblocks
inline bool get_flip_bit() const
{
return (m_bytes[3] & 1) != 0;
}
inline void set_flip_bit(bool flip)
{
m_bytes[3] &= ~1;
m_bytes[3] |= static_cast<uint8>(flip);
}
inline bool get_diff_bit() const
{
return (m_bytes[3] & 2) != 0;
}
inline void set_diff_bit(bool diff)
{
m_bytes[3] &= ~2;
m_bytes[3] |= (static_cast<uint>(diff) << 1);
}
// Returns intensity modifier table (0-7) used by subblock subblock_id.
// subblock_id=0 left/top (CW 1), 1=right/bottom (CW 2)
inline uint get_inten_table(uint subblock_id) const
{
RG_ETC1_ASSERT(subblock_id < 2);
const uint ofs = subblock_id ? 2 : 5;
return (m_bytes[3] >> ofs) & 7;
}
// Sets intensity modifier table (0-7) used by subblock subblock_id (0 or 1)
inline void set_inten_table(uint subblock_id, uint t)
{
RG_ETC1_ASSERT(subblock_id < 2);
RG_ETC1_ASSERT(t < 8);
const uint ofs = subblock_id ? 2 : 5;
m_bytes[3] &= ~(7 << ofs);
m_bytes[3] |= (t << ofs);
}
// Returned selector value ranges from 0-3 and is a direct index into g_etc1_inten_tables.
inline uint get_selector(uint x, uint y) const
{
RG_ETC1_ASSERT((x | y) < 4);
const uint bit_index = x * 4 + y;
const uint byte_bit_ofs = bit_index & 7;
const uint8 *p = &m_bytes[7 - (bit_index >> 3)];
const uint lsb = (p[0] >> byte_bit_ofs) & 1;
const uint msb = (p[-2] >> byte_bit_ofs) & 1;
const uint val = lsb | (msb << 1);
return g_etc1_to_selector_index[val];
}
// Selector "val" ranges from 0-3 and is a direct index into g_etc1_inten_tables.
inline void set_selector(uint x, uint y, uint val)
{
RG_ETC1_ASSERT((x | y | val) < 4);
const uint bit_index = x * 4 + y;
uint8 *p = &m_bytes[7 - (bit_index >> 3)];
const uint byte_bit_ofs = bit_index & 7;
const uint mask = 1 << byte_bit_ofs;
const uint etc1_val = g_selector_index_to_etc1[val];
const uint lsb = etc1_val & 1;
const uint msb = etc1_val >> 1;
p[0] &= ~mask;
p[0] |= (lsb << byte_bit_ofs);
p[-2] &= ~mask;
p[-2] |= (msb << byte_bit_ofs);
}
inline void set_base4_color(uint idx, uint16 c)
{
if (idx)
{
set_byte_bits(cETC1AbsColor4R2BitOffset, 4, (c >> 8) & 15);
set_byte_bits(cETC1AbsColor4G2BitOffset, 4, (c >> 4) & 15);
set_byte_bits(cETC1AbsColor4B2BitOffset, 4, c & 15);
}
else
{
set_byte_bits(cETC1AbsColor4R1BitOffset, 4, (c >> 8) & 15);
set_byte_bits(cETC1AbsColor4G1BitOffset, 4, (c >> 4) & 15);
set_byte_bits(cETC1AbsColor4B1BitOffset, 4, c & 15);
}
}
inline uint16 get_base4_color(uint idx) const
{
uint r, g, b;
if (idx)
{
r = get_byte_bits(cETC1AbsColor4R2BitOffset, 4);
g = get_byte_bits(cETC1AbsColor4G2BitOffset, 4);
b = get_byte_bits(cETC1AbsColor4B2BitOffset, 4);
}
else
{
r = get_byte_bits(cETC1AbsColor4R1BitOffset, 4);
g = get_byte_bits(cETC1AbsColor4G1BitOffset, 4);
b = get_byte_bits(cETC1AbsColor4B1BitOffset, 4);
}
return static_cast<uint16>(b | (g << 4U) | (r << 8U));
}
inline void set_base5_color(uint16 c)
{
set_byte_bits(cETC1BaseColor5RBitOffset, 5, (c >> 10) & 31);
set_byte_bits(cETC1BaseColor5GBitOffset, 5, (c >> 5) & 31);
set_byte_bits(cETC1BaseColor5BBitOffset, 5, c & 31);
}
inline uint16 get_base5_color() const
{
const uint r = get_byte_bits(cETC1BaseColor5RBitOffset, 5);
const uint g = get_byte_bits(cETC1BaseColor5GBitOffset, 5);
const uint b = get_byte_bits(cETC1BaseColor5BBitOffset, 5);
return static_cast<uint16>(b | (g << 5U) | (r << 10U));
}
void set_delta3_color(uint16 c)
{
set_byte_bits(cETC1DeltaColor3RBitOffset, 3, (c >> 6) & 7);
set_byte_bits(cETC1DeltaColor3GBitOffset, 3, (c >> 3) & 7);
set_byte_bits(cETC1DeltaColor3BBitOffset, 3, c & 7);
}
inline uint16 get_delta3_color() const
{
const uint r = get_byte_bits(cETC1DeltaColor3RBitOffset, 3);
const uint g = get_byte_bits(cETC1DeltaColor3GBitOffset, 3);
const uint b = get_byte_bits(cETC1DeltaColor3BBitOffset, 3);
return static_cast<uint16>(b | (g << 3U) | (r << 6U));
}
// Base color 5
static uint16 pack_color5(const color_quad_u8& color, bool scaled, uint bias = 127U);
static uint16 pack_color5(uint r, uint g, uint b, bool scaled, uint bias = 127U);
static color_quad_u8 unpack_color5(uint16 packed_color5, bool scaled, uint alpha = 255U);
static void unpack_color5(uint& r, uint& g, uint& b, uint16 packed_color, bool scaled);
static bool unpack_color5(color_quad_u8& result, uint16 packed_color5, uint16 packed_delta3, bool scaled, uint alpha = 255U);
static bool unpack_color5(uint& r, uint& g, uint& b, uint16 packed_color5, uint16 packed_delta3, bool scaled, uint alpha = 255U);
// Delta color 3
// Inputs range from -4 to 3 (cETC1ColorDeltaMin to cETC1ColorDeltaMax)
static uint16 pack_delta3(int r, int g, int b);
// Results range from -4 to 3 (cETC1ColorDeltaMin to cETC1ColorDeltaMax)
static void unpack_delta3(int& r, int& g, int& b, uint16 packed_delta3);
// Abs color 4
static uint16 pack_color4(const color_quad_u8& color, bool scaled, uint bias = 127U);
static uint16 pack_color4(uint r, uint g, uint b, bool scaled, uint bias = 127U);
static color_quad_u8 unpack_color4(uint16 packed_color4, bool scaled, uint alpha = 255U);
static void unpack_color4(uint& r, uint& g, uint& b, uint16 packed_color4, bool scaled);
// subblock colors
static void get_diff_subblock_colors(color_quad_u8* pDst, uint16 packed_color5, uint table_idx);
static bool get_diff_subblock_colors(color_quad_u8* pDst, uint16 packed_color5, uint16 packed_delta3, uint table_idx);
static void get_abs_subblock_colors(color_quad_u8* pDst, uint16 packed_color4, uint table_idx);
static inline void unscaled_to_scaled_color(color_quad_u8& dst, const color_quad_u8& src, bool color4)
{
if (color4)
{
dst.r = src.r | (src.r << 4);
dst.g = src.g | (src.g << 4);
dst.b = src.b | (src.b << 4);
}
else
{
dst.r = (src.r >> 2) | (src.r << 3);
dst.g = (src.g >> 2) | (src.g << 3);
dst.b = (src.b >> 2) | (src.b << 3);
}
dst.a = src.a;
}
};
// Returns pointer to sorted array.
template<typename T, typename Q>
T* indirect_radix_sort(uint num_indices, T* pIndices0, T* pIndices1, const Q* pKeys, uint key_ofs, uint key_size, bool init_indices)
{
RG_ETC1_ASSERT((key_ofs >= 0) && (key_ofs < sizeof(T)));
RG_ETC1_ASSERT((key_size >= 1) && (key_size <= 4));
if (init_indices)
{
T* p = pIndices0;
T* q = pIndices0 + (num_indices >> 1) * 2;
uint i;
for (i = 0; p != q; p += 2, i += 2)
{
p[0] = static_cast<T>(i);
p[1] = static_cast<T>(i + 1);
}
if (num_indices & 1)
*p = static_cast<T>(i);
}
uint hist[256 * 4];
memset(hist, 0, sizeof(hist[0]) * 256 * key_size);
#define RG_ETC1_GET_KEY(p) (*(const uint*)((const uint8*)(pKeys + *(p)) + key_ofs))
#define RG_ETC1_GET_KEY_FROM_INDEX(i) (*(const uint*)((const uint8*)(pKeys + (i)) + key_ofs))
if (key_size == 4)
{
T* p = pIndices0;
T* q = pIndices0 + num_indices;
for ( ; p != q; p++)
{
const uint key = RG_ETC1_GET_KEY(p);
hist[ key & 0xFF]++;
hist[256 + ((key >> 8) & 0xFF)]++;
hist[512 + ((key >> 16) & 0xFF)]++;
hist[768 + ((key >> 24) & 0xFF)]++;
}
}
else if (key_size == 3)
{
T* p = pIndices0;
T* q = pIndices0 + num_indices;
for ( ; p != q; p++)
{
const uint key = RG_ETC1_GET_KEY(p);
hist[ key & 0xFF]++;
hist[256 + ((key >> 8) & 0xFF)]++;
hist[512 + ((key >> 16) & 0xFF)]++;
}
}
else if (key_size == 2)
{
T* p = pIndices0;
T* q = pIndices0 + (num_indices >> 1) * 2;
for ( ; p != q; p += 2)
{
const uint key0 = RG_ETC1_GET_KEY(p);
const uint key1 = RG_ETC1_GET_KEY(p+1);
hist[ key0 & 0xFF]++;
hist[256 + ((key0 >> 8) & 0xFF)]++;
hist[ key1 & 0xFF]++;
hist[256 + ((key1 >> 8) & 0xFF)]++;
}
if (num_indices & 1)
{
const uint key = RG_ETC1_GET_KEY(p);
hist[ key & 0xFF]++;
hist[256 + ((key >> 8) & 0xFF)]++;
}
}
else
{
RG_ETC1_ASSERT(key_size == 1);
if (key_size != 1)
return NULL;
T* p = pIndices0;
T* q = pIndices0 + (num_indices >> 1) * 2;
for ( ; p != q; p += 2)
{
const uint key0 = RG_ETC1_GET_KEY(p);
const uint key1 = RG_ETC1_GET_KEY(p+1);
hist[key0 & 0xFF]++;
hist[key1 & 0xFF]++;
}
if (num_indices & 1)
{
const uint key = RG_ETC1_GET_KEY(p);
hist[key & 0xFF]++;
}
}
T* pCur = pIndices0;
T* pNew = pIndices1;
for (uint pass = 0; pass < key_size; pass++)
{
const uint* pHist = &hist[pass << 8];
uint offsets[256];
uint cur_ofs = 0;
for (uint i = 0; i < 256; i += 2)
{
offsets[i] = cur_ofs;
cur_ofs += pHist[i];
offsets[i+1] = cur_ofs;
cur_ofs += pHist[i+1];
}
const uint pass_shift = pass << 3;
T* p = pCur;
T* q = pCur + (num_indices >> 1) * 2;
for ( ; p != q; p += 2)
{
uint index0 = p[0];
uint index1 = p[1];
uint c0 = (RG_ETC1_GET_KEY_FROM_INDEX(index0) >> pass_shift) & 0xFF;
uint c1 = (RG_ETC1_GET_KEY_FROM_INDEX(index1) >> pass_shift) & 0xFF;
if (c0 == c1)
{
uint dst_offset0 = offsets[c0];
offsets[c0] = dst_offset0 + 2;
pNew[dst_offset0] = static_cast<T>(index0);
pNew[dst_offset0 + 1] = static_cast<T>(index1);
}
else
{
uint dst_offset0 = offsets[c0]++;
uint dst_offset1 = offsets[c1]++;
pNew[dst_offset0] = static_cast<T>(index0);
pNew[dst_offset1] = static_cast<T>(index1);
}
}
if (num_indices & 1)
{
uint index = *p;
uint c = (RG_ETC1_GET_KEY_FROM_INDEX(index) >> pass_shift) & 0xFF;
uint dst_offset = offsets[c];
offsets[c] = dst_offset + 1;
pNew[dst_offset] = static_cast<T>(index);
}
T* t = pCur;
pCur = pNew;
pNew = t;
}
return pCur;
}
#undef RG_ETC1_GET_KEY
#undef RG_ETC1_GET_KEY_FROM_INDEX
uint16 etc1_block::pack_color5(const color_quad_u8& color, bool scaled, uint bias)
{
return pack_color5(color.r, color.g, color.b, scaled, bias);
}
uint16 etc1_block::pack_color5(uint r, uint g, uint b, bool scaled, uint bias)
{
if (scaled)
{
r = (r * 31U + bias) / 255U;
g = (g * 31U + bias) / 255U;
b = (b * 31U + bias) / 255U;
}
r = rg_etc1::minimum(r, 31U);
g = rg_etc1::minimum(g, 31U);
b = rg_etc1::minimum(b, 31U);
return static_cast<uint16>(b | (g << 5U) | (r << 10U));
}
color_quad_u8 etc1_block::unpack_color5(uint16 packed_color5, bool scaled, uint alpha)
{
uint b = packed_color5 & 31U;
uint g = (packed_color5 >> 5U) & 31U;
uint r = (packed_color5 >> 10U) & 31U;
if (scaled)
{
b = (b << 3U) | (b >> 2U);
g = (g << 3U) | (g >> 2U);
r = (r << 3U) | (r >> 2U);
}
return color_quad_u8(cNoClamp, r, g, b, rg_etc1::minimum(alpha, 255U));
}
void etc1_block::unpack_color5(uint& r, uint& g, uint& b, uint16 packed_color5, bool scaled)
{
color_quad_u8 c(unpack_color5(packed_color5, scaled, 0));
r = c.r;
g = c.g;
b = c.b;
}
bool etc1_block::unpack_color5(color_quad_u8& result, uint16 packed_color5, uint16 packed_delta3, bool scaled, uint alpha)
{
int dc_r, dc_g, dc_b;
unpack_delta3(dc_r, dc_g, dc_b, packed_delta3);
int b = (packed_color5 & 31U) + dc_b;
int g = ((packed_color5 >> 5U) & 31U) + dc_g;
int r = ((packed_color5 >> 10U) & 31U) + dc_r;
bool success = true;
if (static_cast<uint>(r | g | b) > 31U)
{
success = false;
r = rg_etc1::clamp<int>(r, 0, 31);
g = rg_etc1::clamp<int>(g, 0, 31);
b = rg_etc1::clamp<int>(b, 0, 31);
}
if (scaled)
{
b = (b << 3U) | (b >> 2U);
g = (g << 3U) | (g >> 2U);
r = (r << 3U) | (r >> 2U);
}
result.set_noclamp_rgba(r, g, b, rg_etc1::minimum(alpha, 255U));
return success;
}
bool etc1_block::unpack_color5(uint& r, uint& g, uint& b, uint16 packed_color5, uint16 packed_delta3, bool scaled, uint alpha)
{
color_quad_u8 result;
const bool success = unpack_color5(result, packed_color5, packed_delta3, scaled, alpha);
r = result.r;
g = result.g;
b = result.b;
return success;
}
uint16 etc1_block::pack_delta3(int r, int g, int b)
{
RG_ETC1_ASSERT((r >= cETC1ColorDeltaMin) && (r <= cETC1ColorDeltaMax));
RG_ETC1_ASSERT((g >= cETC1ColorDeltaMin) && (g <= cETC1ColorDeltaMax));
RG_ETC1_ASSERT((b >= cETC1ColorDeltaMin) && (b <= cETC1ColorDeltaMax));
if (r < 0) r += 8;
if (g < 0) g += 8;
if (b < 0) b += 8;
return static_cast<uint16>(b | (g << 3) | (r << 6));
}
void etc1_block::unpack_delta3(int& r, int& g, int& b, uint16 packed_delta3)
{
r = (packed_delta3 >> 6) & 7;
g = (packed_delta3 >> 3) & 7;
b = packed_delta3 & 7;
if (r >= 4) r -= 8;
if (g >= 4) g -= 8;
if (b >= 4) b -= 8;
}
uint16 etc1_block::pack_color4(const color_quad_u8& color, bool scaled, uint bias)
{
return pack_color4(color.r, color.g, color.b, scaled, bias);
}
uint16 etc1_block::pack_color4(uint r, uint g, uint b, bool scaled, uint bias)
{
if (scaled)
{
r = (r * 15U + bias) / 255U;
g = (g * 15U + bias) / 255U;
b = (b * 15U + bias) / 255U;
}
r = rg_etc1::minimum(r, 15U);
g = rg_etc1::minimum(g, 15U);
b = rg_etc1::minimum(b, 15U);
return static_cast<uint16>(b | (g << 4U) | (r << 8U));
}
color_quad_u8 etc1_block::unpack_color4(uint16 packed_color4, bool scaled, uint alpha)
{
uint b = packed_color4 & 15U;
uint g = (packed_color4 >> 4U) & 15U;
uint r = (packed_color4 >> 8U) & 15U;
if (scaled)
{
b = (b << 4U) | b;
g = (g << 4U) | g;
r = (r << 4U) | r;
}
return color_quad_u8(cNoClamp, r, g, b, rg_etc1::minimum(alpha, 255U));
}
void etc1_block::unpack_color4(uint& r, uint& g, uint& b, uint16 packed_color4, bool scaled)
{
color_quad_u8 c(unpack_color4(packed_color4, scaled, 0));
r = c.r;
g = c.g;
b = c.b;
}
void etc1_block::get_diff_subblock_colors(color_quad_u8* pDst, uint16 packed_color5, uint table_idx)
{
RG_ETC1_ASSERT(table_idx < cETC1IntenModifierValues);
const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
uint r, g, b;
unpack_color5(r, g, b, packed_color5, true);
const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
const int y0 = pInten_modifer_table[0];
pDst[0].set(ir + y0, ig + y0, ib + y0);
const int y1 = pInten_modifer_table[1];
pDst[1].set(ir + y1, ig + y1, ib + y1);
const int y2 = pInten_modifer_table[2];
pDst[2].set(ir + y2, ig + y2, ib + y2);
const int y3 = pInten_modifer_table[3];
pDst[3].set(ir + y3, ig + y3, ib + y3);
}
bool etc1_block::get_diff_subblock_colors(color_quad_u8* pDst, uint16 packed_color5, uint16 packed_delta3, uint table_idx)
{
RG_ETC1_ASSERT(table_idx < cETC1IntenModifierValues);
const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
uint r, g, b;
bool success = unpack_color5(r, g, b, packed_color5, packed_delta3, true);
const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
const int y0 = pInten_modifer_table[0];
pDst[0].set(ir + y0, ig + y0, ib + y0);
const int y1 = pInten_modifer_table[1];
pDst[1].set(ir + y1, ig + y1, ib + y1);
const int y2 = pInten_modifer_table[2];
pDst[2].set(ir + y2, ig + y2, ib + y2);
const int y3 = pInten_modifer_table[3];
pDst[3].set(ir + y3, ig + y3, ib + y3);
return success;
}
void etc1_block::get_abs_subblock_colors(color_quad_u8* pDst, uint16 packed_color4, uint table_idx)
{
RG_ETC1_ASSERT(table_idx < cETC1IntenModifierValues);
const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
uint r, g, b;
unpack_color4(r, g, b, packed_color4, true);
const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
const int y0 = pInten_modifer_table[0];
pDst[0].set(ir + y0, ig + y0, ib + y0);
const int y1 = pInten_modifer_table[1];
pDst[1].set(ir + y1, ig + y1, ib + y1);
const int y2 = pInten_modifer_table[2];
pDst[2].set(ir + y2, ig + y2, ib + y2);
const int y3 = pInten_modifer_table[3];
pDst[3].set(ir + y3, ig + y3, ib + y3);
}
bool unpack_etc1_block(const void* pETC1_block, unsigned int* pDst_pixels_rgba, bool preserve_alpha)
{
color_quad_u8* pDst = reinterpret_cast<color_quad_u8*>(pDst_pixels_rgba);
const etc1_block& block = *static_cast<const etc1_block*>(pETC1_block);
const bool diff_flag = block.get_diff_bit();
const bool flip_flag = block.get_flip_bit();
const uint table_index0 = block.get_inten_table(0);
const uint table_index1 = block.get_inten_table(1);
color_quad_u8 subblock_colors0[4];
color_quad_u8 subblock_colors1[4];
bool success = true;
if (diff_flag)
{
const uint16 base_color5 = block.get_base5_color();
const uint16 delta_color3 = block.get_delta3_color();
etc1_block::get_diff_subblock_colors(subblock_colors0, base_color5, table_index0);
if (!etc1_block::get_diff_subblock_colors(subblock_colors1, base_color5, delta_color3, table_index1))
success = false;
}
else
{
const uint16 base_color4_0 = block.get_base4_color(0);
etc1_block::get_abs_subblock_colors(subblock_colors0, base_color4_0, table_index0);
const uint16 base_color4_1 = block.get_base4_color(1);
etc1_block::get_abs_subblock_colors(subblock_colors1, base_color4_1, table_index1);
}
if (preserve_alpha)
{
if (flip_flag)
{
for (uint y = 0; y < 2; y++)
{
pDst[0].set_rgb(subblock_colors0[block.get_selector(0, y)]);
pDst[1].set_rgb(subblock_colors0[block.get_selector(1, y)]);
pDst[2].set_rgb(subblock_colors0[block.get_selector(2, y)]);
pDst[3].set_rgb(subblock_colors0[block.get_selector(3, y)]);
pDst += 4;
}
for (uint y = 2; y < 4; y++)
{
pDst[0].set_rgb(subblock_colors1[block.get_selector(0, y)]);
pDst[1].set_rgb(subblock_colors1[block.get_selector(1, y)]);
pDst[2].set_rgb(subblock_colors1[block.get_selector(2, y)]);
pDst[3].set_rgb(subblock_colors1[block.get_selector(3, y)]);
pDst += 4;
}
}
else
{
for (uint y = 0; y < 4; y++)
{
pDst[0].set_rgb(subblock_colors0[block.get_selector(0, y)]);
pDst[1].set_rgb(subblock_colors0[block.get_selector(1, y)]);
pDst[2].set_rgb(subblock_colors1[block.get_selector(2, y)]);
pDst[3].set_rgb(subblock_colors1[block.get_selector(3, y)]);
pDst += 4;
}
}
}
else
{
if (flip_flag)
{
// 0000
// 0000
// 1111
// 1111
for (uint y = 0; y < 2; y++)
{
pDst[0] = subblock_colors0[block.get_selector(0, y)];
pDst[1] = subblock_colors0[block.get_selector(1, y)];
pDst[2] = subblock_colors0[block.get_selector(2, y)];
pDst[3] = subblock_colors0[block.get_selector(3, y)];
pDst += 4;
}
for (uint y = 2; y < 4; y++)
{
pDst[0] = subblock_colors1[block.get_selector(0, y)];
pDst[1] = subblock_colors1[block.get_selector(1, y)];
pDst[2] = subblock_colors1[block.get_selector(2, y)];
pDst[3] = subblock_colors1[block.get_selector(3, y)];
pDst += 4;
}
}
else
{
// 0011
// 0011
// 0011
// 0011
for (uint y = 0; y < 4; y++)
{
pDst[0] = subblock_colors0[block.get_selector(0, y)];
pDst[1] = subblock_colors0[block.get_selector(1, y)];
pDst[2] = subblock_colors1[block.get_selector(2, y)];
pDst[3] = subblock_colors1[block.get_selector(3, y)];
pDst += 4;
}
}
}
return success;
}
struct etc1_solution_coordinates
{
inline etc1_solution_coordinates() :
m_unscaled_color(0, 0, 0, 0),
m_inten_table(0),
m_color4(false)
{
}
inline etc1_solution_coordinates(uint r, uint g, uint b, uint inten_table, bool color4) :
m_unscaled_color(r, g, b, 255),
m_inten_table(inten_table),
m_color4(color4)
{
}
inline etc1_solution_coordinates(const color_quad_u8& c, uint inten_table, bool color4) :
m_unscaled_color(c),
m_inten_table(inten_table),
m_color4(color4)
{
}
inline etc1_solution_coordinates(const etc1_solution_coordinates& other)
{
*this = other;
}
inline etc1_solution_coordinates& operator= (const etc1_solution_coordinates& rhs)
{
m_unscaled_color = rhs.m_unscaled_color;
m_inten_table = rhs.m_inten_table;
m_color4 = rhs.m_color4;
return *this;
}
inline void clear()
{
m_unscaled_color.clear();
m_inten_table = 0;
m_color4 = false;
}
inline color_quad_u8 get_scaled_color() const
{
int br, bg, bb;
if (m_color4)
{
br = m_unscaled_color.r | (m_unscaled_color.r << 4);
bg = m_unscaled_color.g | (m_unscaled_color.g << 4);
bb = m_unscaled_color.b | (m_unscaled_color.b << 4);
}
else
{
br = (m_unscaled_color.r >> 2) | (m_unscaled_color.r << 3);
bg = (m_unscaled_color.g >> 2) | (m_unscaled_color.g << 3);
bb = (m_unscaled_color.b >> 2) | (m_unscaled_color.b << 3);
}
return color_quad_u8(br, bg, bb);
}
inline void get_block_colors(color_quad_u8* pBlock_colors)
{
int br, bg, bb;
if (m_color4)
{
br = m_unscaled_color.r | (m_unscaled_color.r << 4);
bg = m_unscaled_color.g | (m_unscaled_color.g << 4);
bb = m_unscaled_color.b | (m_unscaled_color.b << 4);
}
else
{
br = (m_unscaled_color.r >> 2) | (m_unscaled_color.r << 3);
bg = (m_unscaled_color.g >> 2) | (m_unscaled_color.g << 3);
bb = (m_unscaled_color.b >> 2) | (m_unscaled_color.b << 3);
}
const int* pInten_table = g_etc1_inten_tables[m_inten_table];
pBlock_colors[0].set(br + pInten_table[0], bg + pInten_table[0], bb + pInten_table[0]);
pBlock_colors[1].set(br + pInten_table[1], bg + pInten_table[1], bb + pInten_table[1]);
pBlock_colors[2].set(br + pInten_table[2], bg + pInten_table[2], bb + pInten_table[2]);
pBlock_colors[3].set(br + pInten_table[3], bg + pInten_table[3], bb + pInten_table[3]);
}
color_quad_u8 m_unscaled_color;
uint m_inten_table;
bool m_color4;
};
class etc1_optimizer
{
etc1_optimizer(const etc1_optimizer&);
etc1_optimizer& operator= (const etc1_optimizer&);
public:
etc1_optimizer()
{
clear();
}
void clear()
{
m_pParams = NULL;
m_pResult = NULL;
m_pSorted_luma = NULL;
m_pSorted_luma_indices = NULL;
}
struct params : etc1_pack_params
{
params()
{
clear();
}
params(const etc1_pack_params& base_params) :
etc1_pack_params(base_params)
{
clear_optimizer_params();
}
void clear()
{
etc1_pack_params::clear();
clear_optimizer_params();
}
void clear_optimizer_params()
{
m_num_src_pixels = 0;
m_pSrc_pixels = 0;
m_use_color4 = false;
static const int s_default_scan_delta[] = { 0 };
m_pScan_deltas = s_default_scan_delta;
m_scan_delta_size = 1;
m_base_color5.clear();
m_constrain_against_base_color5 = false;
}
uint m_num_src_pixels;
const color_quad_u8* m_pSrc_pixels;
bool m_use_color4;
const int* m_pScan_deltas;
uint m_scan_delta_size;
color_quad_u8 m_base_color5;
bool m_constrain_against_base_color5;
};
struct results
{
uint64 m_error;
color_quad_u8 m_block_color_unscaled;
uint m_block_inten_table;
uint m_n;
uint8* m_pSelectors;
bool m_block_color4;
inline results& operator= (const results& rhs)
{
m_block_color_unscaled = rhs.m_block_color_unscaled;
m_block_color4 = rhs.m_block_color4;
m_block_inten_table = rhs.m_block_inten_table;
m_error = rhs.m_error;
RG_ETC1_ASSERT(m_n == rhs.m_n);
memcpy(m_pSelectors, rhs.m_pSelectors, rhs.m_n);
return *this;
}
};
void init(const params& params, results& result);
bool compute();
private:
struct potential_solution
{
potential_solution() : m_coords(), m_error(cUINT64_MAX), m_valid(false)
{
}
etc1_solution_coordinates m_coords;
uint8 m_selectors[8];
uint64 m_error;
bool m_valid;
void clear()
{
m_coords.clear();
m_error = cUINT64_MAX;
m_valid = false;
}
};
const params* m_pParams;
results* m_pResult;
int m_limit;
vec3F m_avg_color;
int m_br, m_bg, m_bb;
uint16 m_luma[8];
uint32 m_sorted_luma[2][8];
const uint32* m_pSorted_luma_indices;
uint32* m_pSorted_luma;
uint8 m_selectors[8];
uint8 m_best_selectors[8];
potential_solution m_best_solution;
potential_solution m_trial_solution;
uint8 m_temp_selectors[8];
bool evaluate_solution(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution);
bool evaluate_solution_fast(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution);
};
bool etc1_optimizer::compute()
{
const uint n = m_pParams->m_num_src_pixels;
const int scan_delta_size = m_pParams->m_scan_delta_size;
// Scan through a subset of the 3D lattice centered around the avg block color trying each 3D (555 or 444) lattice point as a potential block color.
// Each time a better solution is found try to refine the current solution's block color based of the current selectors and intensity table index.
for (int zdi = 0; zdi < scan_delta_size; zdi++)
{
const int zd = m_pParams->m_pScan_deltas[zdi];
const int mbb = m_bb + zd;
if (mbb < 0) continue; else if (mbb > m_limit) break;
for (int ydi = 0; ydi < scan_delta_size; ydi++)
{
const int yd = m_pParams->m_pScan_deltas[ydi];
const int mbg = m_bg + yd;
if (mbg < 0) continue; else if (mbg > m_limit) break;
for (int xdi = 0; xdi < scan_delta_size; xdi++)
{
const int xd = m_pParams->m_pScan_deltas[xdi];
const int mbr = m_br + xd;
if (mbr < 0) continue; else if (mbr > m_limit) break;
etc1_solution_coordinates coords(mbr, mbg, mbb, 0, m_pParams->m_use_color4);
if (m_pParams->m_quality == cHighQuality)
{
if (!evaluate_solution(coords, m_trial_solution, &m_best_solution))
continue;
}
else
{
if (!evaluate_solution_fast(coords, m_trial_solution, &m_best_solution))
continue;
}
// Now we have the input block, the avg. color of the input pixels, a set of trial selector indices, and the block color+intensity index.
// Now, for each component, attempt to refine the current solution by solving a simple linear equation. For example, for 4 colors:
// The goal is:
// pixel0 - (block_color+inten_table[selector0]) + pixel1 - (block_color+inten_table[selector1]) + pixel2 - (block_color+inten_table[selector2]) + pixel3 - (block_color+inten_table[selector3]) = 0
// Rearranging this:
// (pixel0 + pixel1 + pixel2 + pixel3) - (block_color+inten_table[selector0]) - (block_color+inten_table[selector1]) - (block_color+inten_table[selector2]) - (block_color+inten_table[selector3]) = 0
// (pixel0 + pixel1 + pixel2 + pixel3) - block_color - inten_table[selector0] - block_color-inten_table[selector1] - block_color-inten_table[selector2] - block_color-inten_table[selector3] = 0
// (pixel0 + pixel1 + pixel2 + pixel3) - 4*block_color - inten_table[selector0] - inten_table[selector1] - inten_table[selector2] - inten_table[selector3] = 0
// (pixel0 + pixel1 + pixel2 + pixel3) - 4*block_color - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3]) = 0
// (pixel0 + pixel1 + pixel2 + pixel3)/4 - block_color - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3])/4 = 0
// block_color = (pixel0 + pixel1 + pixel2 + pixel3)/4 - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3])/4
// So what this means:
// optimal_block_color = avg_input - avg_inten_delta
// So the optimal block color can be computed by taking the average block color and subtracting the current average of the intensity delta.
// Unfortunately, optimal_block_color must then be quantized to 555 or 444 so it's not always possible to improve matters using this formula.
// Also, the above formula is for unclamped intensity deltas. The actual implementation takes into account clamping.
const uint max_refinement_trials = (m_pParams->m_quality == cLowQuality) ? 2 : (((xd | yd | zd) == 0) ? 4 : 2);
for (uint refinement_trial = 0; refinement_trial < max_refinement_trials; refinement_trial++)
{
const uint8* pSelectors = m_best_solution.m_selectors;
const int* pInten_table = g_etc1_inten_tables[m_best_solution.m_coords.m_inten_table];
int delta_sum_r = 0, delta_sum_g = 0, delta_sum_b = 0;
const color_quad_u8 base_color(m_best_solution.m_coords.get_scaled_color());
for (uint r = 0; r < n; r++)
{
const uint s = *pSelectors++;
const int yd = pInten_table[s];
// Compute actual delta being applied to each pixel, taking into account clamping.
delta_sum_r += rg_etc1::clamp<int>(base_color.r + yd, 0, 255) - base_color.r;
delta_sum_g += rg_etc1::clamp<int>(base_color.g + yd, 0, 255) - base_color.g;
delta_sum_b += rg_etc1::clamp<int>(base_color.b + yd, 0, 255) - base_color.b;
}
if ((!delta_sum_r) && (!delta_sum_g) && (!delta_sum_b))
break;
const float avg_delta_r_f = static_cast<float>(delta_sum_r) / n;
const float avg_delta_g_f = static_cast<float>(delta_sum_g) / n;
const float avg_delta_b_f = static_cast<float>(delta_sum_b) / n;
const int br1 = rg_etc1::clamp<int>(static_cast<uint>((m_avg_color[0] - avg_delta_r_f) * m_limit / 255.0f + .5f), 0, m_limit);
const int bg1 = rg_etc1::clamp<int>(static_cast<uint>((m_avg_color[1] - avg_delta_g_f) * m_limit / 255.0f + .5f), 0, m_limit);
const int bb1 = rg_etc1::clamp<int>(static_cast<uint>((m_avg_color[2] - avg_delta_b_f) * m_limit / 255.0f + .5f), 0, m_limit);
bool skip = false;
if ((mbr == br1) && (mbg == bg1) && (mbb == bb1))
skip = true;
else if ((br1 == m_best_solution.m_coords.m_unscaled_color.r) && (bg1 == m_best_solution.m_coords.m_unscaled_color.g) && (bb1 == m_best_solution.m_coords.m_unscaled_color.b))
skip = true;
else if ((m_br == br1) && (m_bg == bg1) && (m_bb == bb1))
skip = true;
if (skip)
break;
etc1_solution_coordinates coords1(br1, bg1, bb1, 0, m_pParams->m_use_color4);
if (m_pParams->m_quality == cHighQuality)
{
if (!evaluate_solution(coords1, m_trial_solution, &m_best_solution))
break;
}
else
{
if (!evaluate_solution_fast(coords1, m_trial_solution, &m_best_solution))
break;
}
} // refinement_trial
} // xdi
} // ydi
} // zdi
if (!m_best_solution.m_valid)
{
m_pResult->m_error = cUINT32_MAX;
return false;
}
const uint8* pSelectors = m_best_solution.m_selectors;
#ifdef RG_ETC1_BUILD_DEBUG
{
color_quad_u8 block_colors[4];
m_best_solution.m_coords.get_block_colors(block_colors);
const color_quad_u8* pSrc_pixels = m_pParams->m_pSrc_pixels;
uint64 actual_error = 0;
for (uint i = 0; i < n; i++)
actual_error += pSrc_pixels[i].squared_distance_rgb(block_colors[pSelectors[i]]);
RG_ETC1_ASSERT(actual_error == m_best_solution.m_error);
}
#endif
m_pResult->m_error = m_best_solution.m_error;
m_pResult->m_block_color_unscaled = m_best_solution.m_coords.m_unscaled_color;
m_pResult->m_block_color4 = m_best_solution.m_coords.m_color4;
m_pResult->m_block_inten_table = m_best_solution.m_coords.m_inten_table;
memcpy(m_pResult->m_pSelectors, pSelectors, n);
m_pResult->m_n = n;
return true;
}
void etc1_optimizer::init(const params& p, results& r)
{
// This version is hardcoded for 8 pixel subblocks.
RG_ETC1_ASSERT(p.m_num_src_pixels == 8);
m_pParams = &p;
m_pResult = &r;
const uint n = 8;
m_limit = m_pParams->m_use_color4 ? 15 : 31;
vec3F avg_color(0.0f);
for (uint i = 0; i < n; i++)
{
const color_quad_u8& c = m_pParams->m_pSrc_pixels[i];
const vec3F fc(c.r, c.g, c.b);
avg_color += fc;
m_luma[i] = static_cast<uint16>(c.r + c.g + c.b);
m_sorted_luma[0][i] = i;
}
avg_color *= (1.0f / static_cast<float>(n));
m_avg_color = avg_color;
m_br = rg_etc1::clamp<int>(static_cast<uint>(m_avg_color[0] * m_limit / 255.0f + .5f), 0, m_limit);
m_bg = rg_etc1::clamp<int>(static_cast<uint>(m_avg_color[1] * m_limit / 255.0f + .5f), 0, m_limit);
m_bb = rg_etc1::clamp<int>(static_cast<uint>(m_avg_color[2] * m_limit / 255.0f + .5f), 0, m_limit);
if (m_pParams->m_quality <= cMediumQuality)
{
m_pSorted_luma_indices = indirect_radix_sort(n, m_sorted_luma[0], m_sorted_luma[1], m_luma, 0, sizeof(m_luma[0]), false);
m_pSorted_luma = m_sorted_luma[0];
if (m_pSorted_luma_indices == m_sorted_luma[0])
m_pSorted_luma = m_sorted_luma[1];
for (uint i = 0; i < n; i++)
m_pSorted_luma[i] = m_luma[m_pSorted_luma_indices[i]];
}
m_best_solution.m_coords.clear();
m_best_solution.m_valid = false;
m_best_solution.m_error = cUINT64_MAX;
}
bool etc1_optimizer::evaluate_solution(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution)
{
trial_solution.m_valid = false;
if (m_pParams->m_constrain_against_base_color5)
{
const int dr = coords.m_unscaled_color.r - m_pParams->m_base_color5.r;
const int dg = coords.m_unscaled_color.g - m_pParams->m_base_color5.g;
const int db = coords.m_unscaled_color.b - m_pParams->m_base_color5.b;
if ((rg_etc1::minimum(dr, dg, db) < cETC1ColorDeltaMin) || (rg_etc1::maximum(dr, dg, db) > cETC1ColorDeltaMax))
return false;
}
const color_quad_u8 base_color(coords.get_scaled_color());
const uint n = 8;
trial_solution.m_error = cUINT64_MAX;
for (uint inten_table = 0; inten_table < cETC1IntenModifierValues; inten_table++)
{
const int* pInten_table = g_etc1_inten_tables[inten_table];
color_quad_u8 block_colors[4];
for (uint s = 0; s < 4; s++)
{
const int yd = pInten_table[s];
block_colors[s].set(base_color.r + yd, base_color.g + yd, base_color.b + yd, 0);
}
uint64 total_error = 0;
const color_quad_u8* pSrc_pixels = m_pParams->m_pSrc_pixels;
for (uint c = 0; c < n; c++)
{
const color_quad_u8& src_pixel = *pSrc_pixels++;
uint best_selector_index = 0;
uint best_error = rg_etc1::square(src_pixel.r - block_colors[0].r) + rg_etc1::square(src_pixel.g - block_colors[0].g) + rg_etc1::square(src_pixel.b - block_colors[0].b);
uint trial_error = rg_etc1::square(src_pixel.r - block_colors[1].r) + rg_etc1::square(src_pixel.g - block_colors[1].g) + rg_etc1::square(src_pixel.b - block_colors[1].b);
if (trial_error < best_error)
{
best_error = trial_error;
best_selector_index = 1;
}
trial_error = rg_etc1::square(src_pixel.r - block_colors[2].r) + rg_etc1::square(src_pixel.g - block_colors[2].g) + rg_etc1::square(src_pixel.b - block_colors[2].b);
if (trial_error < best_error)
{
best_error = trial_error;
best_selector_index = 2;
}
trial_error = rg_etc1::square(src_pixel.r - block_colors[3].r) + rg_etc1::square(src_pixel.g - block_colors[3].g) + rg_etc1::square(src_pixel.b - block_colors[3].b);
if (trial_error < best_error)
{
best_error = trial_error;
best_selector_index = 3;
}
m_temp_selectors[c] = static_cast<uint8>(best_selector_index);
total_error += best_error;
if (total_error >= trial_solution.m_error)
break;
}
if (total_error < trial_solution.m_error)
{
trial_solution.m_error = total_error;
trial_solution.m_coords.m_inten_table = inten_table;
memcpy(trial_solution.m_selectors, m_temp_selectors, 8);
trial_solution.m_valid = true;
}
}
trial_solution.m_coords.m_unscaled_color = coords.m_unscaled_color;
trial_solution.m_coords.m_color4 = m_pParams->m_use_color4;
bool success = false;
if (pBest_solution)
{
if (trial_solution.m_error < pBest_solution->m_error)
{
*pBest_solution = trial_solution;
success = true;
}
}
return success;
}
bool etc1_optimizer::evaluate_solution_fast(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution)
{
if (m_pParams->m_constrain_against_base_color5)
{
const int dr = coords.m_unscaled_color.r - m_pParams->m_base_color5.r;
const int dg = coords.m_unscaled_color.g - m_pParams->m_base_color5.g;
const int db = coords.m_unscaled_color.b - m_pParams->m_base_color5.b;
if ((rg_etc1::minimum(dr, dg, db) < cETC1ColorDeltaMin) || (rg_etc1::maximum(dr, dg, db) > cETC1ColorDeltaMax))
{
trial_solution.m_valid = false;
return false;
}
}
const color_quad_u8 base_color(coords.get_scaled_color());
const uint n = 8;
trial_solution.m_error = cUINT64_MAX;
for (int inten_table = cETC1IntenModifierValues - 1; inten_table >= 0; --inten_table)
{
const int* pInten_table = g_etc1_inten_tables[inten_table];
uint block_inten[4];
color_quad_u8 block_colors[4];
for (uint s = 0; s < 4; s++)
{
const int yd = pInten_table[s];
color_quad_u8 block_color(base_color.r + yd, base_color.g + yd, base_color.b + yd, 0);
block_colors[s] = block_color;
block_inten[s] = block_color.r + block_color.g + block_color.b;
}
// evaluate_solution_fast() enforces/assumesd a total ordering of the input colors along the intensity (1,1,1) axis to more quickly classify the inputs to selectors.
// The inputs colors have been presorted along the projection onto this axis, and ETC1 block colors are always ordered along the intensity axis, so this classification is fast.
// 0 1 2 3
// 01 12 23
const uint block_inten_midpoints[3] = { block_inten[0] + block_inten[1], block_inten[1] + block_inten[2], block_inten[2] + block_inten[3] };
uint64 total_error = 0;
const color_quad_u8* pSrc_pixels = m_pParams->m_pSrc_pixels;
if ((m_pSorted_luma[n - 1] * 2) < block_inten_midpoints[0])
{
if (block_inten[0] > m_pSorted_luma[n - 1])
{
const uint min_error = intabs(block_inten[0] - m_pSorted_luma[n - 1]);
if (min_error >= trial_solution.m_error)
continue;
}
memset(&m_temp_selectors[0], 0, n);
for (uint c = 0; c < n; c++)
total_error += block_colors[0].squared_distance_rgb(pSrc_pixels[c]);
}
else if ((m_pSorted_luma[0] * 2) >= block_inten_midpoints[2])
{
if (m_pSorted_luma[0] > block_inten[3])
{
const uint min_error = intabs(m_pSorted_luma[0] - block_inten[3]);
if (min_error >= trial_solution.m_error)
continue;
}
memset(&m_temp_selectors[0], 3, n);
for (uint c = 0; c < n; c++)
total_error += block_colors[3].squared_distance_rgb(pSrc_pixels[c]);
}
else
{
uint cur_selector = 0, c;
for (c = 0; c < n; c++)
{
const uint y = m_pSorted_luma[c];
while ((y * 2) >= block_inten_midpoints[cur_selector])
if (++cur_selector > 2)
goto done;
const uint sorted_pixel_index = m_pSorted_luma_indices[c];
m_temp_selectors[sorted_pixel_index] = static_cast<uint8>(cur_selector);
total_error += block_colors[cur_selector].squared_distance_rgb(pSrc_pixels[sorted_pixel_index]);
}
done:
while (c < n)
{
const uint sorted_pixel_index = m_pSorted_luma_indices[c];
m_temp_selectors[sorted_pixel_index] = 3;
total_error += block_colors[3].squared_distance_rgb(pSrc_pixels[sorted_pixel_index]);
++c;
}
}
if (total_error < trial_solution.m_error)
{
trial_solution.m_error = total_error;
trial_solution.m_coords.m_inten_table = inten_table;
memcpy(trial_solution.m_selectors, m_temp_selectors, n);
trial_solution.m_valid = true;
if (!total_error)
break;
}
}
trial_solution.m_coords.m_unscaled_color = coords.m_unscaled_color;
trial_solution.m_coords.m_color4 = m_pParams->m_use_color4;
bool success = false;
if (pBest_solution)
{
if (trial_solution.m_error < pBest_solution->m_error)
{
*pBest_solution = trial_solution;
success = true;
}
}
return success;
}
static uint etc1_decode_value(uint diff, uint inten, uint selector, uint packed_c)
{
const uint limit = diff ? 32 : 16; limit;
RG_ETC1_ASSERT((diff < 2) && (inten < 8) && (selector < 4) && (packed_c < limit));
int c;
if (diff)
c = (packed_c >> 2) | (packed_c << 3);
else
c = packed_c | (packed_c << 4);
c += g_etc1_inten_tables[inten][selector];
c = rg_etc1::clamp<int>(c, 0, 255);
return c;
}
static inline int mul_8bit(int a, int b) { int t = a*b + 128; return (t + (t >> 8)) >> 8; }
void pack_etc1_block_init()
{
for (uint diff = 0; diff < 2; diff++)
{
const uint limit = diff ? 32 : 16;
for (uint inten = 0; inten < 8; inten++)
{
for (uint selector = 0; selector < 4; selector++)
{
const uint inverse_table_index = diff + (inten << 1) + (selector << 4);
for (uint color = 0; color < 256; color++)
{
uint best_error = cUINT32_MAX, best_packed_c = 0;
for (uint packed_c = 0; packed_c < limit; packed_c++)
{
int v = etc1_decode_value(diff, inten, selector, packed_c);
uint err = intabs(v - color);
//printf("err: %d - %u = %u\n",v,color,err);
if (err < best_error)
{
best_error = err;
best_packed_c = packed_c;
if (!best_error)
break;
}
}
RG_ETC1_ASSERT(best_error <= 255);
g_etc1_inverse_lookup[inverse_table_index][color] = static_cast<uint16>(best_packed_c | (best_error << 8));
}
}
}
}
uint expand5[32];
for(int i = 0; i < 32; i++)
expand5[i] = (i << 3) | (i >> 2);
for(int i = 0; i < 256 + 16; i++)
{
int v = clamp<int>(i - 8, 0, 255);
g_quant5_tab[i] = static_cast<uint8>(expand5[mul_8bit(v,31)]);
}
}
// Packs solid color blocks efficiently using a set of small precomputed tables.
// For random 888 inputs, MSE results are better than Erricson's ETC1 packer in "slow" mode ~9.5% of the time, is slightly worse only ~.01% of the time, and is equal the rest of the time.
static uint64 pack_etc1_block_solid_color(etc1_block& block, const uint8* pColor, etc1_pack_params& pack_params)
{
pack_params;
RG_ETC1_ASSERT(g_etc1_inverse_lookup[0][255]);
static uint s_next_comp[4] = { 1, 2, 0, 1 };
uint best_error = cUINT32_MAX, best_i = 0;
int best_x = 0, best_packed_c1 = 0, best_packed_c2 = 0;
// For each possible 8-bit value, there is a precomputed list of diff/inten/selector configurations that allow that 8-bit value to be encoded with no error.
for (uint i = 0; i < 3; i++)
{
const uint c1 = pColor[s_next_comp[i]], c2 = pColor[s_next_comp[i + 1]];
const int delta_range = 1;
for (int delta = -delta_range; delta <= delta_range; delta++)
{
const int c_plus_delta = rg_etc1::clamp<int>(pColor[i] + delta, 0, 255);
const uint16* pTable;
if (!c_plus_delta)
pTable = g_color8_to_etc_block_config_0_255[0];
else if (c_plus_delta == 255)
pTable = g_color8_to_etc_block_config_0_255[1];
else
pTable = g_color8_to_etc_block_config_1_to_254[c_plus_delta - 1];
do
{
const uint x = *pTable++;
#ifdef RG_ETC1_BUILD_DEBUG
const uint diff = x & 1;
const uint inten = (x >> 1) & 7;
const uint selector = (x >> 4) & 3;
const uint p0 = (x >> 8) & 255;
RG_ETC1_ASSERT(etc1_decode_value(diff, inten, selector, p0) == (uint)c_plus_delta);
#endif
const uint16* pInverse_table = g_etc1_inverse_lookup[x & 0xFF];
uint16 p1 = pInverse_table[c1];
uint16 p2 = pInverse_table[c2];
const uint trial_error = rg_etc1::square(c_plus_delta - pColor[i]) + rg_etc1::square(p1 >> 8) + rg_etc1::square(p2 >> 8);
if (trial_error < best_error)
{
best_error = trial_error;
best_x = x;
best_packed_c1 = p1 & 0xFF;
best_packed_c2 = p2 & 0xFF;
best_i = i;
if (!best_error)
goto found_perfect_match;
}
} while (*pTable != 0xFFFF);
}
}
found_perfect_match:
const uint diff = best_x & 1;
const uint inten = (best_x >> 1) & 7;
block.m_bytes[3] = static_cast<uint8>(((inten | (inten << 3)) << 2) | (diff << 1));
const uint etc1_selector = g_selector_index_to_etc1[(best_x >> 4) & 3];
*reinterpret_cast<uint16*>(&block.m_bytes[4]) = (etc1_selector & 2) ? 0xFFFF : 0;
*reinterpret_cast<uint16*>(&block.m_bytes[6]) = (etc1_selector & 1) ? 0xFFFF : 0;
const uint best_packed_c0 = (best_x >> 8) & 255;
if (diff)
{
block.m_bytes[best_i] = static_cast<uint8>(best_packed_c0 << 3);
block.m_bytes[s_next_comp[best_i]] = static_cast<uint8>(best_packed_c1 << 3);
block.m_bytes[s_next_comp[best_i+1]] = static_cast<uint8>(best_packed_c2 << 3);
}
else
{
block.m_bytes[best_i] = static_cast<uint8>(best_packed_c0 | (best_packed_c0 << 4));
block.m_bytes[s_next_comp[best_i]] = static_cast<uint8>(best_packed_c1 | (best_packed_c1 << 4));
block.m_bytes[s_next_comp[best_i+1]] = static_cast<uint8>(best_packed_c2 | (best_packed_c2 << 4));
}
return best_error;
}
static uint pack_etc1_block_solid_color_constrained(
etc1_optimizer::results& results,
uint num_colors, const uint8* pColor,
etc1_pack_params& pack_params,
bool use_diff,
const color_quad_u8* pBase_color5_unscaled)
{
RG_ETC1_ASSERT(g_etc1_inverse_lookup[0][255]);
pack_params;
static uint s_next_comp[4] = { 1, 2, 0, 1 };
uint best_error = cUINT32_MAX, best_i = 0;
int best_x = 0, best_packed_c1 = 0, best_packed_c2 = 0;
// For each possible 8-bit value, there is a precomputed list of diff/inten/selector configurations that allow that 8-bit value to be encoded with no error.
for (uint i = 0; i < 3; i++)
{
const uint c1 = pColor[s_next_comp[i]], c2 = pColor[s_next_comp[i + 1]];
const int delta_range = 1;
for (int delta = -delta_range; delta <= delta_range; delta++)
{
const int c_plus_delta = rg_etc1::clamp<int>(pColor[i] + delta, 0, 255);
const uint16* pTable;
if (!c_plus_delta)
pTable = g_color8_to_etc_block_config_0_255[0];
else if (c_plus_delta == 255)
pTable = g_color8_to_etc_block_config_0_255[1];
else
pTable = g_color8_to_etc_block_config_1_to_254[c_plus_delta - 1];
do
{
const uint x = *pTable++;
const uint diff = x & 1;
if (static_cast<uint>(use_diff) != diff)
{
if (*pTable == 0xFFFF)
break;
continue;
}
if ((diff) && (pBase_color5_unscaled))
{
const int p0 = (x >> 8) & 255;
int delta = p0 - static_cast<int>(pBase_color5_unscaled->c[i]);
if ((delta < cETC1ColorDeltaMin) || (delta > cETC1ColorDeltaMax))
{
if (*pTable == 0xFFFF)
break;
continue;
}
}
#ifdef RG_ETC1_BUILD_DEBUG
{
const uint inten = (x >> 1) & 7;
const uint selector = (x >> 4) & 3;
const uint p0 = (x >> 8) & 255;
RG_ETC1_ASSERT(etc1_decode_value(diff, inten, selector, p0) == (uint)c_plus_delta);
}
#endif
const uint16* pInverse_table = g_etc1_inverse_lookup[x & 0xFF];
uint16 p1 = pInverse_table[c1];
uint16 p2 = pInverse_table[c2];
if ((diff) && (pBase_color5_unscaled))
{
int delta1 = (p1 & 0xFF) - static_cast<int>(pBase_color5_unscaled->c[s_next_comp[i]]);
int delta2 = (p2 & 0xFF) - static_cast<int>(pBase_color5_unscaled->c[s_next_comp[i + 1]]);
if ((delta1 < cETC1ColorDeltaMin) || (delta1 > cETC1ColorDeltaMax) || (delta2 < cETC1ColorDeltaMin) || (delta2 > cETC1ColorDeltaMax))
{
if (*pTable == 0xFFFF)
break;
continue;
}
}
const uint trial_error = rg_etc1::square(c_plus_delta - pColor[i]) + rg_etc1::square(p1 >> 8) + rg_etc1::square(p2 >> 8);
if (trial_error < best_error)
{
best_error = trial_error;
best_x = x;
best_packed_c1 = p1 & 0xFF;
best_packed_c2 = p2 & 0xFF;
best_i = i;
if (!best_error)
goto found_perfect_match;
}
} while (*pTable != 0xFFFF);
}
}
found_perfect_match:
if (best_error == cUINT32_MAX)
return best_error;
best_error *= num_colors;
results.m_n = num_colors;
results.m_block_color4 = !(best_x & 1);
results.m_block_inten_table = (best_x >> 1) & 7;
memset(results.m_pSelectors, (best_x >> 4) & 3, num_colors);
const uint best_packed_c0 = (best_x >> 8) & 255;
results.m_block_color_unscaled[best_i] = static_cast<uint8>(best_packed_c0);
results.m_block_color_unscaled[s_next_comp[best_i]] = static_cast<uint8>(best_packed_c1);
results.m_block_color_unscaled[s_next_comp[best_i + 1]] = static_cast<uint8>(best_packed_c2);
results.m_error = best_error;
return best_error;
}
// Function originally from RYG's public domain real-time DXT1 compressor, modified for 555.
static void dither_block_555(color_quad_u8* dest, const color_quad_u8* block)
{
int err[8],*ep1 = err,*ep2 = err+4;
uint8 *quant = g_quant5_tab+8;
memset(dest, 0xFF, sizeof(color_quad_u8)*16);
// process channels seperately
for(int ch=0;ch<3;ch++)
{
uint8* bp = (uint8*)block;
uint8* dp = (uint8*)dest;
bp += ch; dp += ch;
memset(err,0, sizeof(err));
for(int y = 0; y < 4; y++)
{
// pixel 0
dp[ 0] = quant[bp[ 0] + ((3*ep2[1] + 5*ep2[0]) >> 4)];
ep1[0] = bp[ 0] - dp[ 0];
// pixel 1
dp[ 4] = quant[bp[ 4] + ((7*ep1[0] + 3*ep2[2] + 5*ep2[1] + ep2[0]) >> 4)];
ep1[1] = bp[ 4] - dp[ 4];
// pixel 2
dp[ 8] = quant[bp[ 8] + ((7*ep1[1] + 3*ep2[3] + 5*ep2[2] + ep2[1]) >> 4)];
ep1[2] = bp[ 8] - dp[ 8];
// pixel 3
dp[12] = quant[bp[12] + ((7*ep1[2] + 5*ep2[3] + ep2[2]) >> 4)];
ep1[3] = bp[12] - dp[12];
// advance to next line
int* tmp = ep1; ep1 = ep2; ep2 = tmp;
bp += 16;
dp += 16;
}
}
}
unsigned int pack_etc1_block(void* pETC1_block, const unsigned int* pSrc_pixels_rgba, etc1_pack_params& pack_params)
{
const color_quad_u8* pSrc_pixels = reinterpret_cast<const color_quad_u8*>(pSrc_pixels_rgba);
etc1_block& dst_block = *static_cast<etc1_block*>(pETC1_block);
#ifdef RG_ETC1_BUILD_DEBUG
// Ensure all alpha values are 0xFF.
for (uint i = 0; i < 16; i++)
{
RG_ETC1_ASSERT(pSrc_pixels[i].a == 255);
}
#endif
color_quad_u8 src_pixel0(pSrc_pixels[0]);
// Check for solid block.
const uint32 first_pixel_u32 = pSrc_pixels->m_u32;
int r;
for (r = 15; r >= 1; --r)
if (pSrc_pixels[r].m_u32 != first_pixel_u32)
break;
if (!r)
return static_cast<unsigned int>(16 * pack_etc1_block_solid_color(dst_block, &pSrc_pixels[0].r, pack_params));
color_quad_u8 dithered_pixels[16];
if (pack_params.m_dithering)
{
dither_block_555(dithered_pixels, pSrc_pixels);
pSrc_pixels = dithered_pixels;
}
etc1_optimizer optimizer;
uint64 best_error = cUINT64_MAX;
uint best_flip = false, best_use_color4 = false;
uint8 best_selectors[2][8];
etc1_optimizer::results best_results[2];
for (uint i = 0; i < 2; i++)
{
best_results[i].m_n = 8;
best_results[i].m_pSelectors = best_selectors[i];
}
uint8 selectors[3][8];
etc1_optimizer::results results[3];
for (uint i = 0; i < 3; i++)
{
results[i].m_n = 8;
results[i].m_pSelectors = selectors[i];
}
color_quad_u8 subblock_pixels[8];
etc1_optimizer::params params(pack_params);
params.m_num_src_pixels = 8;
params.m_pSrc_pixels = subblock_pixels;
for (uint flip = 0; flip < 2; flip++)
{
for (uint use_color4 = 0; use_color4 < 2; use_color4++)
{
uint64 trial_error = 0;
uint subblock;
for (subblock = 0; subblock < 2; subblock++)
{
if (flip)
memcpy(subblock_pixels, pSrc_pixels + subblock * 8, sizeof(color_quad_u8) * 8);
else
{
const color_quad_u8* pSrc_col = pSrc_pixels + subblock * 2;
subblock_pixels[0] = pSrc_col[0]; subblock_pixels[1] = pSrc_col[4]; subblock_pixels[2] = pSrc_col[8]; subblock_pixels[3] = pSrc_col[12];
subblock_pixels[4] = pSrc_col[1]; subblock_pixels[5] = pSrc_col[5]; subblock_pixels[6] = pSrc_col[9]; subblock_pixels[7] = pSrc_col[13];
}
results[2].m_error = cUINT64_MAX;
if ((params.m_quality >= cMediumQuality) && ((subblock) || (use_color4)))
{
const uint32 subblock_pixel0_u32 = subblock_pixels[0].m_u32;
for (r = 7; r >= 1; --r)
if (subblock_pixels[r].m_u32 != subblock_pixel0_u32)
break;
if (!r)
{
pack_etc1_block_solid_color_constrained(results[2], 8, &subblock_pixels[0].r, pack_params, !use_color4, (subblock && !use_color4) ? &results[0].m_block_color_unscaled : NULL);
}
}
params.m_use_color4 = (use_color4 != 0);
params.m_constrain_against_base_color5 = false;
if ((!use_color4) && (subblock))
{
params.m_constrain_against_base_color5 = true;
params.m_base_color5 = results[0].m_block_color_unscaled;
}
if (params.m_quality == cHighQuality)
{
static const int s_scan_delta_0_to_4[] = { -4, -3, -2, -1, 0, 1, 2, 3, 4 };
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_0_to_4);
params.m_pScan_deltas = s_scan_delta_0_to_4;
}
else if (params.m_quality == cMediumQuality)
{
static const int s_scan_delta_0_to_1[] = { -1, 0, 1 };
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_0_to_1);
params.m_pScan_deltas = s_scan_delta_0_to_1;
}
else
{
static const int s_scan_delta_0[] = { 0 };
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_0);
params.m_pScan_deltas = s_scan_delta_0;
}
optimizer.init(params, results[subblock]);
if (!optimizer.compute())
break;
if (params.m_quality >= cMediumQuality)
{
// TODO: Fix fairly arbitrary/unrefined thresholds that control how far away to scan for potentially better solutions.
const uint refinement_error_thresh0 = 3000;
const uint refinement_error_thresh1 = 6000;
if (results[subblock].m_error > refinement_error_thresh0)
{
if (params.m_quality == cMediumQuality)
{
static const int s_scan_delta_2_to_3[] = { -3, -2, 2, 3 };
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_2_to_3);
params.m_pScan_deltas = s_scan_delta_2_to_3;
}
else
{
static const int s_scan_delta_5_to_5[] = { -5, 5 };
static const int s_scan_delta_5_to_8[] = { -8, -7, -6, -5, 5, 6, 7, 8 };
if (results[subblock].m_error > refinement_error_thresh1)
{
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_5_to_8);
params.m_pScan_deltas = s_scan_delta_5_to_8;
}
else
{
params.m_scan_delta_size = RG_ETC1_ARRAY_SIZE(s_scan_delta_5_to_5);
params.m_pScan_deltas = s_scan_delta_5_to_5;
}
}
if (!optimizer.compute())
break;
}
if (results[2].m_error < results[subblock].m_error)
results[subblock] = results[2];
}
trial_error += results[subblock].m_error;
if (trial_error >= best_error)
break;
}
if (subblock < 2)
continue;
best_error = trial_error;
best_results[0] = results[0];
best_results[1] = results[1];
best_flip = flip;
best_use_color4 = use_color4;
} // use_color4
} // flip
int dr = best_results[1].m_block_color_unscaled.r - best_results[0].m_block_color_unscaled.r;
int dg = best_results[1].m_block_color_unscaled.g - best_results[0].m_block_color_unscaled.g;
int db = best_results[1].m_block_color_unscaled.b - best_results[0].m_block_color_unscaled.b;
RG_ETC1_ASSERT(best_use_color4 || (rg_etc1::minimum(dr, dg, db) >= cETC1ColorDeltaMin) && (rg_etc1::maximum(dr, dg, db) <= cETC1ColorDeltaMax));
if (best_use_color4)
{
dst_block.m_bytes[0] = static_cast<uint8>(best_results[1].m_block_color_unscaled.r | (best_results[0].m_block_color_unscaled.r << 4));
dst_block.m_bytes[1] = static_cast<uint8>(best_results[1].m_block_color_unscaled.g | (best_results[0].m_block_color_unscaled.g << 4));
dst_block.m_bytes[2] = static_cast<uint8>(best_results[1].m_block_color_unscaled.b | (best_results[0].m_block_color_unscaled.b << 4));
}
else
{
if (dr < 0) dr += 8; dst_block.m_bytes[0] = static_cast<uint8>((best_results[0].m_block_color_unscaled.r << 3) | dr);
if (dg < 0) dg += 8; dst_block.m_bytes[1] = static_cast<uint8>((best_results[0].m_block_color_unscaled.g << 3) | dg);
if (db < 0) db += 8; dst_block.m_bytes[2] = static_cast<uint8>((best_results[0].m_block_color_unscaled.b << 3) | db);
}
dst_block.m_bytes[3] = static_cast<uint8>( (best_results[1].m_block_inten_table << 2) | (best_results[0].m_block_inten_table << 5) | ((~best_use_color4 & 1) << 1) | best_flip );
uint selector0 = 0, selector1 = 0;
if (best_flip)
{
// flipped:
// { 0, 0 }, { 1, 0 }, { 2, 0 }, { 3, 0 },
// { 0, 1 }, { 1, 1 }, { 2, 1 }, { 3, 1 }
//
// { 0, 2 }, { 1, 2 }, { 2, 2 }, { 3, 2 },
// { 0, 3 }, { 1, 3 }, { 2, 3 }, { 3, 3 }
const uint8* pSelectors0 = best_results[0].m_pSelectors;
const uint8* pSelectors1 = best_results[1].m_pSelectors;
for (int x = 3; x >= 0; --x)
{
uint b;
b = g_selector_index_to_etc1[pSelectors1[4 + x]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors1[x]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors0[4 + x]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors0[x]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
}
}
else
{
// non-flipped:
// { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 },
// { 1, 0 }, { 1, 1 }, { 1, 2 }, { 1, 3 }
//
// { 2, 0 }, { 2, 1 }, { 2, 2 }, { 2, 3 },
// { 3, 0 }, { 3, 1 }, { 3, 2 }, { 3, 3 }
for (int subblock = 1; subblock >= 0; --subblock)
{
const uint8* pSelectors = best_results[subblock].m_pSelectors + 4;
for (uint i = 0; i < 2; i++)
{
uint b;
b = g_selector_index_to_etc1[pSelectors[3]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors[2]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors[1]];
selector0 = (selector0 << 1) | (b & 1); selector1 = (selector1 << 1) | (b >> 1);
b = g_selector_index_to_etc1[pSelectors[0]];
selector0 = (selector0 << 1) | (b & 1);selector1 = (selector1 << 1) | (b >> 1);
pSelectors -= 4;
}
}
}
dst_block.m_bytes[4] = static_cast<uint8>(selector1 >> 8); dst_block.m_bytes[5] = static_cast<uint8>(selector1 & 0xFF);
dst_block.m_bytes[6] = static_cast<uint8>(selector0 >> 8); dst_block.m_bytes[7] = static_cast<uint8>(selector0 & 0xFF);
return static_cast<unsigned int>(best_error);
}
} // namespace rg_etc1
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