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godot/thirdparty/basis_universal/transcoder/basisu_transcoder_internal.h
BlueCube3310 200ed0971a BasisU: Update to 1.50.0 and add HDR support
2024-10-12 18:02:44 +02:00

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// basisu_transcoder_internal.h - Universal texture format transcoder library.
// Copyright (C) 2019-2024 Binomial LLC. All Rights Reserved.
//
// Important: If compiling with gcc, be sure strict aliasing is disabled: -fno-strict-aliasing
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#ifdef _MSC_VER
#pragma warning (disable: 4127) // conditional expression is constant
#endif
// v1.50: Added UASTC HDR support
#define BASISD_LIB_VERSION 150
#define BASISD_VERSION_STRING "01.50"
#ifdef _DEBUG
#define BASISD_BUILD_DEBUG
#else
#define BASISD_BUILD_RELEASE
#endif
#include "basisu.h"
#define BASISD_znew (z = 36969 * (z & 65535) + (z >> 16))
namespace basisu
{
extern bool g_debug_printf;
}
namespace basist
{
// Low-level formats directly supported by the transcoder (other supported texture formats are combinations of these low-level block formats).
// You probably don't care about these enum's unless you are going pretty low-level and calling the transcoder to decode individual slices.
enum class block_format
{
cETC1, // ETC1S RGB
cETC2_RGBA, // full ETC2 EAC RGBA8 block
cBC1, // DXT1 RGB
cBC3, // BC4 block followed by a four color BC1 block
cBC4, // DXT5A (alpha block only)
cBC5, // two BC4 blocks
cPVRTC1_4_RGB, // opaque-only PVRTC1 4bpp
cPVRTC1_4_RGBA, // PVRTC1 4bpp RGBA
cBC7, // Full BC7 block, any mode
cBC7_M5_COLOR, // RGB BC7 mode 5 color (writes an opaque mode 5 block)
cBC7_M5_ALPHA, // alpha portion of BC7 mode 5 (cBC7_M5_COLOR output data must have been written to the output buffer first to set the mode/rot fields etc.)
cETC2_EAC_A8, // alpha block of ETC2 EAC (first 8 bytes of the 16-bit ETC2 EAC RGBA format)
cASTC_4x4, // ASTC 4x4 (either color-only or color+alpha). Note that the transcoder always currently assumes sRGB is not enabled when outputting ASTC
// data. If you use a sRGB ASTC format you'll get ~1 LSB of additional error, because of the different way ASTC decoders scale 8-bit endpoints to 16-bits during unpacking.
cATC_RGB,
cATC_RGBA_INTERPOLATED_ALPHA,
cFXT1_RGB, // Opaque-only, has oddball 8x4 pixel block size
cPVRTC2_4_RGB,
cPVRTC2_4_RGBA,
cETC2_EAC_R11,
cETC2_EAC_RG11,
cIndices, // Used internally: Write 16-bit endpoint and selector indices directly to output (output block must be at least 32-bits)
cRGB32, // Writes RGB components to 32bpp output pixels
cRGBA32, // Writes RGB255 components to 32bpp output pixels
cA32, // Writes alpha component to 32bpp output pixels
cRGB565,
cBGR565,
cRGBA4444_COLOR,
cRGBA4444_ALPHA,
cRGBA4444_COLOR_OPAQUE,
cRGBA4444,
cRGBA_HALF,
cRGB_HALF,
cRGB_9E5,
cUASTC_4x4, // LDR, universal
cUASTC_HDR_4x4, // HDR, transcodes only to 4x4 HDR ASTC, BC6H, or uncompressed
cBC6H,
cASTC_HDR_4x4,
cTotalBlockFormats
};
const int COLOR5_PAL0_PREV_HI = 9, COLOR5_PAL0_DELTA_LO = -9, COLOR5_PAL0_DELTA_HI = 31;
const int COLOR5_PAL1_PREV_HI = 21, COLOR5_PAL1_DELTA_LO = -21, COLOR5_PAL1_DELTA_HI = 21;
const int COLOR5_PAL2_PREV_HI = 31, COLOR5_PAL2_DELTA_LO = -31, COLOR5_PAL2_DELTA_HI = 9;
const int COLOR5_PAL_MIN_DELTA_B_RUNLEN = 3, COLOR5_PAL_DELTA_5_RUNLEN_VLC_BITS = 3;
const uint32_t ENDPOINT_PRED_TOTAL_SYMBOLS = (4 * 4 * 4 * 4) + 1;
const uint32_t ENDPOINT_PRED_REPEAT_LAST_SYMBOL = ENDPOINT_PRED_TOTAL_SYMBOLS - 1;
const uint32_t ENDPOINT_PRED_MIN_REPEAT_COUNT = 3;
const uint32_t ENDPOINT_PRED_COUNT_VLC_BITS = 4;
const uint32_t NUM_ENDPOINT_PREDS = 3;// BASISU_ARRAY_SIZE(g_endpoint_preds);
const uint32_t CR_ENDPOINT_PRED_INDEX = NUM_ENDPOINT_PREDS - 1;
const uint32_t NO_ENDPOINT_PRED_INDEX = 3;//NUM_ENDPOINT_PREDS;
const uint32_t MAX_SELECTOR_HISTORY_BUF_SIZE = 64;
const uint32_t SELECTOR_HISTORY_BUF_RLE_COUNT_THRESH = 3;
const uint32_t SELECTOR_HISTORY_BUF_RLE_COUNT_BITS = 6;
const uint32_t SELECTOR_HISTORY_BUF_RLE_COUNT_TOTAL = (1 << SELECTOR_HISTORY_BUF_RLE_COUNT_BITS);
uint16_t crc16(const void *r, size_t size, uint16_t crc);
class huffman_decoding_table
{
friend class bitwise_decoder;
public:
huffman_decoding_table()
{
}
void clear()
{
basisu::clear_vector(m_code_sizes);
basisu::clear_vector(m_lookup);
basisu::clear_vector(m_tree);
}
bool init(uint32_t total_syms, const uint8_t *pCode_sizes, uint32_t fast_lookup_bits = basisu::cHuffmanFastLookupBits)
{
if (!total_syms)
{
clear();
return true;
}
m_code_sizes.resize(total_syms);
memcpy(&m_code_sizes[0], pCode_sizes, total_syms);
const uint32_t huffman_fast_lookup_size = 1 << fast_lookup_bits;
m_lookup.resize(0);
m_lookup.resize(huffman_fast_lookup_size);
m_tree.resize(0);
m_tree.resize(total_syms * 2);
uint32_t syms_using_codesize[basisu::cHuffmanMaxSupportedInternalCodeSize + 1];
basisu::clear_obj(syms_using_codesize);
for (uint32_t i = 0; i < total_syms; i++)
{
if (pCode_sizes[i] > basisu::cHuffmanMaxSupportedInternalCodeSize)
return false;
syms_using_codesize[pCode_sizes[i]]++;
}
uint32_t next_code[basisu::cHuffmanMaxSupportedInternalCodeSize + 1];
next_code[0] = next_code[1] = 0;
uint32_t used_syms = 0, total = 0;
for (uint32_t i = 1; i < basisu::cHuffmanMaxSupportedInternalCodeSize; i++)
{
used_syms += syms_using_codesize[i];
next_code[i + 1] = (total = ((total + syms_using_codesize[i]) << 1));
}
if (((1U << basisu::cHuffmanMaxSupportedInternalCodeSize) != total) && (used_syms != 1U))
return false;
for (int tree_next = -1, sym_index = 0; sym_index < (int)total_syms; ++sym_index)
{
uint32_t rev_code = 0, l, cur_code, code_size = pCode_sizes[sym_index];
if (!code_size)
continue;
cur_code = next_code[code_size]++;
for (l = code_size; l > 0; l--, cur_code >>= 1)
rev_code = (rev_code << 1) | (cur_code & 1);
if (code_size <= fast_lookup_bits)
{
uint32_t k = (code_size << 16) | sym_index;
while (rev_code < huffman_fast_lookup_size)
{
if (m_lookup[rev_code] != 0)
{
// Supplied codesizes can't create a valid prefix code.
return false;
}
m_lookup[rev_code] = k;
rev_code += (1 << code_size);
}
continue;
}
int tree_cur;
if (0 == (tree_cur = m_lookup[rev_code & (huffman_fast_lookup_size - 1)]))
{
const uint32_t idx = rev_code & (huffman_fast_lookup_size - 1);
if (m_lookup[idx] != 0)
{
// Supplied codesizes can't create a valid prefix code.
return false;
}
m_lookup[idx] = tree_next;
tree_cur = tree_next;
tree_next -= 2;
}
if (tree_cur >= 0)
{
// Supplied codesizes can't create a valid prefix code.
return false;
}
rev_code >>= (fast_lookup_bits - 1);
for (int j = code_size; j > ((int)fast_lookup_bits + 1); j--)
{
tree_cur -= ((rev_code >>= 1) & 1);
const int idx = -tree_cur - 1;
if (idx < 0)
return false;
else if (idx >= (int)m_tree.size())
m_tree.resize(idx + 1);
if (!m_tree[idx])
{
m_tree[idx] = (int16_t)tree_next;
tree_cur = tree_next;
tree_next -= 2;
}
else
{
tree_cur = m_tree[idx];
if (tree_cur >= 0)
{
// Supplied codesizes can't create a valid prefix code.
return false;
}
}
}
tree_cur -= ((rev_code >>= 1) & 1);
const int idx = -tree_cur - 1;
if (idx < 0)
return false;
else if (idx >= (int)m_tree.size())
m_tree.resize(idx + 1);
if (m_tree[idx] != 0)
{
// Supplied codesizes can't create a valid prefix code.
return false;
}
m_tree[idx] = (int16_t)sym_index;
}
return true;
}
const basisu::uint8_vec &get_code_sizes() const { return m_code_sizes; }
const basisu::int_vec &get_lookup() const { return m_lookup; }
const basisu::int16_vec &get_tree() const { return m_tree; }
bool is_valid() const { return m_code_sizes.size() > 0; }
private:
basisu::uint8_vec m_code_sizes;
basisu::int_vec m_lookup;
basisu::int16_vec m_tree;
};
class bitwise_decoder
{
public:
bitwise_decoder() :
m_buf_size(0),
m_pBuf(nullptr),
m_pBuf_start(nullptr),
m_pBuf_end(nullptr),
m_bit_buf(0),
m_bit_buf_size(0)
{
}
void clear()
{
m_buf_size = 0;
m_pBuf = nullptr;
m_pBuf_start = nullptr;
m_pBuf_end = nullptr;
m_bit_buf = 0;
m_bit_buf_size = 0;
}
bool init(const uint8_t *pBuf, uint32_t buf_size)
{
if ((!pBuf) && (buf_size))
return false;
m_buf_size = buf_size;
m_pBuf = pBuf;
m_pBuf_start = pBuf;
m_pBuf_end = pBuf + buf_size;
m_bit_buf = 0;
m_bit_buf_size = 0;
return true;
}
void stop()
{
}
inline uint32_t peek_bits(uint32_t num_bits)
{
if (!num_bits)
return 0;
assert(num_bits <= 25);
while (m_bit_buf_size < num_bits)
{
uint32_t c = 0;
if (m_pBuf < m_pBuf_end)
c = *m_pBuf++;
m_bit_buf |= (c << m_bit_buf_size);
m_bit_buf_size += 8;
assert(m_bit_buf_size <= 32);
}
return m_bit_buf & ((1 << num_bits) - 1);
}
void remove_bits(uint32_t num_bits)
{
assert(m_bit_buf_size >= num_bits);
m_bit_buf >>= num_bits;
m_bit_buf_size -= num_bits;
}
uint32_t get_bits(uint32_t num_bits)
{
if (num_bits > 25)
{
assert(num_bits <= 32);
const uint32_t bits0 = peek_bits(25);
m_bit_buf >>= 25;
m_bit_buf_size -= 25;
num_bits -= 25;
const uint32_t bits = peek_bits(num_bits);
m_bit_buf >>= num_bits;
m_bit_buf_size -= num_bits;
return bits0 | (bits << 25);
}
const uint32_t bits = peek_bits(num_bits);
m_bit_buf >>= num_bits;
m_bit_buf_size -= num_bits;
return bits;
}
uint32_t decode_truncated_binary(uint32_t n)
{
assert(n >= 2);
const uint32_t k = basisu::floor_log2i(n);
const uint32_t u = (1 << (k + 1)) - n;
uint32_t result = get_bits(k);
if (result >= u)
result = ((result << 1) | get_bits(1)) - u;
return result;
}
uint32_t decode_rice(uint32_t m)
{
assert(m);
uint32_t q = 0;
for (;;)
{
uint32_t k = peek_bits(16);
uint32_t l = 0;
while (k & 1)
{
l++;
k >>= 1;
}
q += l;
remove_bits(l);
if (l < 16)
break;
}
return (q << m) + (get_bits(m + 1) >> 1);
}
inline uint32_t decode_vlc(uint32_t chunk_bits)
{
assert(chunk_bits);
const uint32_t chunk_size = 1 << chunk_bits;
const uint32_t chunk_mask = chunk_size - 1;
uint32_t v = 0;
uint32_t ofs = 0;
for ( ; ; )
{
uint32_t s = get_bits(chunk_bits + 1);
v |= ((s & chunk_mask) << ofs);
ofs += chunk_bits;
if ((s & chunk_size) == 0)
break;
if (ofs >= 32)
{
assert(0);
break;
}
}
return v;
}
inline uint32_t decode_huffman(const huffman_decoding_table &ct, int fast_lookup_bits = basisu::cHuffmanFastLookupBits)
{
assert(ct.m_code_sizes.size());
const uint32_t huffman_fast_lookup_size = 1 << fast_lookup_bits;
while (m_bit_buf_size < 16)
{
uint32_t c = 0;
if (m_pBuf < m_pBuf_end)
c = *m_pBuf++;
m_bit_buf |= (c << m_bit_buf_size);
m_bit_buf_size += 8;
assert(m_bit_buf_size <= 32);
}
int code_len;
int sym;
if ((sym = ct.m_lookup[m_bit_buf & (huffman_fast_lookup_size - 1)]) >= 0)
{
code_len = sym >> 16;
sym &= 0xFFFF;
}
else
{
code_len = fast_lookup_bits;
do
{
sym = ct.m_tree[~sym + ((m_bit_buf >> code_len++) & 1)]; // ~sym = -sym - 1
} while (sym < 0);
}
m_bit_buf >>= code_len;
m_bit_buf_size -= code_len;
return sym;
}
bool read_huffman_table(huffman_decoding_table &ct)
{
ct.clear();
const uint32_t total_used_syms = get_bits(basisu::cHuffmanMaxSymsLog2);
if (!total_used_syms)
return true;
if (total_used_syms > basisu::cHuffmanMaxSyms)
return false;
uint8_t code_length_code_sizes[basisu::cHuffmanTotalCodelengthCodes];
basisu::clear_obj(code_length_code_sizes);
const uint32_t num_codelength_codes = get_bits(5);
if ((num_codelength_codes < 1) || (num_codelength_codes > basisu::cHuffmanTotalCodelengthCodes))
return false;
for (uint32_t i = 0; i < num_codelength_codes; i++)
code_length_code_sizes[basisu::g_huffman_sorted_codelength_codes[i]] = static_cast<uint8_t>(get_bits(3));
huffman_decoding_table code_length_table;
if (!code_length_table.init(basisu::cHuffmanTotalCodelengthCodes, code_length_code_sizes))
return false;
if (!code_length_table.is_valid())
return false;
basisu::uint8_vec code_sizes(total_used_syms);
uint32_t cur = 0;
while (cur < total_used_syms)
{
int c = decode_huffman(code_length_table);
if (c <= 16)
code_sizes[cur++] = static_cast<uint8_t>(c);
else if (c == basisu::cHuffmanSmallZeroRunCode)
cur += get_bits(basisu::cHuffmanSmallZeroRunExtraBits) + basisu::cHuffmanSmallZeroRunSizeMin;
else if (c == basisu::cHuffmanBigZeroRunCode)
cur += get_bits(basisu::cHuffmanBigZeroRunExtraBits) + basisu::cHuffmanBigZeroRunSizeMin;
else
{
if (!cur)
return false;
uint32_t l;
if (c == basisu::cHuffmanSmallRepeatCode)
l = get_bits(basisu::cHuffmanSmallRepeatExtraBits) + basisu::cHuffmanSmallRepeatSizeMin;
else
l = get_bits(basisu::cHuffmanBigRepeatExtraBits) + basisu::cHuffmanBigRepeatSizeMin;
const uint8_t prev = code_sizes[cur - 1];
if (prev == 0)
return false;
do
{
if (cur >= total_used_syms)
return false;
code_sizes[cur++] = prev;
} while (--l > 0);
}
}
if (cur != total_used_syms)
return false;
return ct.init(total_used_syms, &code_sizes[0]);
}
private:
uint32_t m_buf_size;
const uint8_t *m_pBuf;
const uint8_t *m_pBuf_start;
const uint8_t *m_pBuf_end;
uint32_t m_bit_buf;
uint32_t m_bit_buf_size;
};
inline uint32_t basisd_rand(uint32_t seed)
{
if (!seed)
seed++;
uint32_t z = seed;
BASISD_znew;
return z;
}
// Returns random number in [0,limit). Max limit is 0xFFFF.
inline uint32_t basisd_urand(uint32_t& seed, uint32_t limit)
{
seed = basisd_rand(seed);
return (((seed ^ (seed >> 16)) & 0xFFFF) * limit) >> 16;
}
class approx_move_to_front
{
public:
approx_move_to_front(uint32_t n)
{
init(n);
}
void init(uint32_t n)
{
m_values.resize(n);
m_rover = n / 2;
}
const basisu::int_vec& get_values() const { return m_values; }
basisu::int_vec& get_values() { return m_values; }
uint32_t size() const { return (uint32_t)m_values.size(); }
const int& operator[] (uint32_t index) const { return m_values[index]; }
int operator[] (uint32_t index) { return m_values[index]; }
void add(int new_value)
{
m_values[m_rover++] = new_value;
if (m_rover == m_values.size())
m_rover = (uint32_t)m_values.size() / 2;
}
void use(uint32_t index)
{
if (index)
{
//std::swap(m_values[index / 2], m_values[index]);
int x = m_values[index / 2];
int y = m_values[index];
m_values[index / 2] = y;
m_values[index] = x;
}
}
// returns -1 if not found
int find(int value) const
{
for (uint32_t i = 0; i < m_values.size(); i++)
if (m_values[i] == value)
return i;
return -1;
}
void reset()
{
const uint32_t n = (uint32_t)m_values.size();
m_values.clear();
init(n);
}
private:
basisu::int_vec m_values;
uint32_t m_rover;
};
struct decoder_etc_block;
inline uint8_t clamp255(int32_t i)
{
return (uint8_t)((i & 0xFFFFFF00U) ? (~(i >> 31)) : i);
}
enum eNoClamp
{
cNoClamp = 0
};
struct color32
{
union
{
struct
{
uint8_t r;
uint8_t g;
uint8_t b;
uint8_t a;
};
uint8_t c[4];
uint32_t m;
};
color32() { }
color32(uint32_t vr, uint32_t vg, uint32_t vb, uint32_t va) { set(vr, vg, vb, va); }
color32(eNoClamp unused, uint32_t vr, uint32_t vg, uint32_t vb, uint32_t va) { (void)unused; set_noclamp_rgba(vr, vg, vb, va); }
void set(uint32_t vr, uint32_t vg, uint32_t vb, uint32_t va) { c[0] = static_cast<uint8_t>(vr); c[1] = static_cast<uint8_t>(vg); c[2] = static_cast<uint8_t>(vb); c[3] = static_cast<uint8_t>(va); }
void set_noclamp_rgb(uint32_t vr, uint32_t vg, uint32_t vb) { c[0] = static_cast<uint8_t>(vr); c[1] = static_cast<uint8_t>(vg); c[2] = static_cast<uint8_t>(vb); }
void set_noclamp_rgba(uint32_t vr, uint32_t vg, uint32_t vb, uint32_t va) { set(vr, vg, vb, va); }
void set_clamped(int vr, int vg, int vb, int va) { c[0] = clamp255(vr); c[1] = clamp255(vg); c[2] = clamp255(vb); c[3] = clamp255(va); }
uint8_t operator[] (uint32_t idx) const { assert(idx < 4); return c[idx]; }
uint8_t &operator[] (uint32_t idx) { assert(idx < 4); return c[idx]; }
bool operator== (const color32&rhs) const { return m == rhs.m; }
static color32 comp_min(const color32& a, const color32& b) { return color32(cNoClamp, basisu::minimum(a[0], b[0]), basisu::minimum(a[1], b[1]), basisu::minimum(a[2], b[2]), basisu::minimum(a[3], b[3])); }
static color32 comp_max(const color32& a, const color32& b) { return color32(cNoClamp, basisu::maximum(a[0], b[0]), basisu::maximum(a[1], b[1]), basisu::maximum(a[2], b[2]), basisu::maximum(a[3], b[3])); }
};
struct endpoint
{
color32 m_color5;
uint8_t m_inten5;
bool operator== (const endpoint& rhs) const
{
return (m_color5.r == rhs.m_color5.r) && (m_color5.g == rhs.m_color5.g) && (m_color5.b == rhs.m_color5.b) && (m_inten5 == rhs.m_inten5);
}
bool operator!= (const endpoint& rhs) const { return !(*this == rhs); }
};
struct selector
{
// Plain selectors (2-bits per value)
uint8_t m_selectors[4];
// ETC1 selectors
uint8_t m_bytes[4];
uint8_t m_lo_selector, m_hi_selector;
uint8_t m_num_unique_selectors;
bool operator== (const selector& rhs) const
{
return (m_selectors[0] == rhs.m_selectors[0]) &&
(m_selectors[1] == rhs.m_selectors[1]) &&
(m_selectors[2] == rhs.m_selectors[2]) &&
(m_selectors[3] == rhs.m_selectors[3]);
}
bool operator!= (const selector& rhs) const
{
return !(*this == rhs);
}
void init_flags()
{
uint32_t hist[4] = { 0, 0, 0, 0 };
for (uint32_t y = 0; y < 4; y++)
{
for (uint32_t x = 0; x < 4; x++)
{
uint32_t s = get_selector(x, y);
hist[s]++;
}
}
m_lo_selector = 3;
m_hi_selector = 0;
m_num_unique_selectors = 0;
for (uint32_t i = 0; i < 4; i++)
{
if (hist[i])
{
m_num_unique_selectors++;
if (i < m_lo_selector) m_lo_selector = static_cast<uint8_t>(i);
if (i > m_hi_selector) m_hi_selector = static_cast<uint8_t>(i);
}
}
}
// Returned selector value ranges from 0-3 and is a direct index into g_etc1_inten_tables.
inline uint32_t get_selector(uint32_t x, uint32_t y) const
{
assert((x < 4) && (y < 4));
return (m_selectors[y] >> (x * 2)) & 3;
}
void set_selector(uint32_t x, uint32_t y, uint32_t val)
{
static const uint8_t s_selector_index_to_etc1[4] = { 3, 2, 0, 1 };
assert((x | y | val) < 4);
m_selectors[y] &= ~(3 << (x * 2));
m_selectors[y] |= (val << (x * 2));
const uint32_t etc1_bit_index = x * 4 + y;
uint8_t *p = &m_bytes[3 - (etc1_bit_index >> 3)];
const uint32_t byte_bit_ofs = etc1_bit_index & 7;
const uint32_t mask = 1 << byte_bit_ofs;
const uint32_t etc1_val = s_selector_index_to_etc1[val];
const uint32_t lsb = etc1_val & 1;
const uint32_t msb = etc1_val >> 1;
p[0] &= ~mask;
p[0] |= (lsb << byte_bit_ofs);
p[-2] &= ~mask;
p[-2] |= (msb << byte_bit_ofs);
}
};
bool basis_block_format_is_uncompressed(block_format tex_type);
//------------------------------------
typedef uint16_t half_float;
const double MIN_DENORM_HALF_FLOAT = 0.000000059604645; // smallest positive subnormal number
const double MIN_HALF_FLOAT = 0.00006103515625; // smallest positive normal number
const double MAX_HALF_FLOAT = 65504.0; // largest normal number
inline uint32_t get_bits(uint32_t val, int low, int high)
{
const int num_bits = (high - low) + 1;
assert((num_bits >= 1) && (num_bits <= 32));
val >>= low;
if (num_bits != 32)
val &= ((1u << num_bits) - 1);
return val;
}
inline bool is_half_inf_or_nan(half_float v)
{
return get_bits(v, 10, 14) == 31;
}
inline bool is_half_denorm(half_float v)
{
int e = (v >> 10) & 31;
return !e;
}
inline int get_half_exp(half_float v)
{
int e = ((v >> 10) & 31);
return e ? (e - 15) : -14;
}
inline int get_half_mantissa(half_float v)
{
if (is_half_denorm(v))
return v & 0x3FF;
return (v & 0x3FF) | 0x400;
}
inline float get_half_mantissaf(half_float v)
{
return ((float)get_half_mantissa(v)) / 1024.0f;
}
inline int get_half_sign(half_float v)
{
return v ? ((v & 0x8000) ? -1 : 1) : 0;
}
inline bool half_is_signed(half_float v)
{
return (v & 0x8000) != 0;
}
#if 0
int hexp = get_half_exp(Cf);
float hman = get_half_mantissaf(Cf);
int hsign = get_half_sign(Cf);
float k = powf(2.0f, hexp) * hman * hsign;
if (is_half_inf_or_nan(Cf))
k = std::numeric_limits<float>::quiet_NaN();
#endif
half_float float_to_half(float val);
inline float half_to_float(half_float hval)
{
union { float f; uint32_t u; } x = { 0 };
uint32_t s = ((uint32_t)hval >> 15) & 1;
uint32_t e = ((uint32_t)hval >> 10) & 0x1F;
uint32_t m = (uint32_t)hval & 0x3FF;
if (!e)
{
if (!m)
{
// +- 0
x.u = s << 31;
return x.f;
}
else
{
// denormalized
while (!(m & 0x00000400))
{
m <<= 1;
--e;
}
++e;
m &= ~0x00000400;
}
}
else if (e == 31)
{
if (m == 0)
{
// +/- INF
x.u = (s << 31) | 0x7f800000;
return x.f;
}
else
{
// +/- NaN
x.u = (s << 31) | 0x7f800000 | (m << 13);
return x.f;
}
}
e = e + (127 - 15);
m = m << 13;
assert(s <= 1);
assert(m <= 0x7FFFFF);
assert(e <= 255);
x.u = m | (e << 23) | (s << 31);
return x.f;
}
// Originally from bc6h_enc.h
void bc6h_enc_init();
const uint32_t MAX_BLOG16_VAL = 0xFFFF;
// BC6H internals
const uint32_t NUM_BC6H_MODES = 14;
const uint32_t BC6H_LAST_MODE_INDEX = 13;
const uint32_t BC6H_FIRST_1SUBSET_MODE_INDEX = 10; // in the MS docs, this is "mode 11" (where the first mode is 1), 60 bits for endpoints (10.10, 10.10, 10.10), 63 bits for weights
const uint32_t TOTAL_BC6H_PARTITION_PATTERNS = 32;
extern const uint8_t g_bc6h_mode_sig_bits[NUM_BC6H_MODES][4]; // base, r, g, b
struct bc6h_bit_layout
{
int8_t m_comp; // R=0,G=1,B=2,D=3 (D=partition index)
int8_t m_index; // 0-3, 0-1 Low/High subset 1, 2-3 Low/High subset 2, -1=partition index (d)
int8_t m_last_bit;
int8_t m_first_bit; // may be -1 if a single bit, may be >m_last_bit if reversed
};
const uint32_t MAX_BC6H_LAYOUT_INDEX = 25;
extern const bc6h_bit_layout g_bc6h_bit_layouts[NUM_BC6H_MODES][MAX_BC6H_LAYOUT_INDEX];
extern const uint8_t g_bc6h_2subset_patterns[TOTAL_BC6H_PARTITION_PATTERNS][4][4]; // [y][x]
extern const uint8_t g_bc6h_weight3[8];
extern const uint8_t g_bc6h_weight4[16];
extern const int8_t g_bc6h_mode_lookup[32];
// Converts b16 to half float
inline half_float bc6h_blog16_to_half(uint32_t comp)
{
assert(comp <= 0xFFFF);
// scale the magnitude by 31/64
comp = (comp * 31u) >> 6u;
return (half_float)comp;
}
const uint32_t MAX_BC6H_HALF_FLOAT_AS_UINT = 0x7BFF;
// Inverts bc6h_blog16_to_half().
// Returns the nearest blog16 given a half value.
inline uint32_t bc6h_half_to_blog16(half_float h)
{
assert(h <= MAX_BC6H_HALF_FLOAT_AS_UINT);
return (h * 64 + 30) / 31;
}
struct bc6h_block
{
uint8_t m_bytes[16];
};
void bc6h_enc_block_mode10(bc6h_block* pPacked_block, const half_float pEndpoints[3][2], const uint8_t* pWeights);
void bc6h_enc_block_1subset_4bit_weights(bc6h_block* pPacked_block, const half_float pEndpoints[3][2], const uint8_t* pWeights);
void bc6h_enc_block_1subset_mode9_3bit_weights(bc6h_block* pPacked_block, const half_float pEndpoints[3][2], const uint8_t* pWeights);
void bc6h_enc_block_1subset_3bit_weights(bc6h_block* pPacked_block, const half_float pEndpoints[3][2], const uint8_t* pWeights);
void bc6h_enc_block_2subset_mode9_3bit_weights(bc6h_block* pPacked_block, uint32_t common_part_index, const half_float pEndpoints[2][3][2], const uint8_t* pWeights); // pEndpoints[subset][comp][lh_index]
void bc6h_enc_block_2subset_3bit_weights(bc6h_block* pPacked_block, uint32_t common_part_index, const half_float pEndpoints[2][3][2], const uint8_t* pWeights); // pEndpoints[subset][comp][lh_index]
bool bc6h_enc_block_solid_color(bc6h_block* pPacked_block, const half_float pColor[3]);
} // namespace basist
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