mirror of
https://github.com/godotengine/godot.git
synced 2024-12-15 10:12:40 +08:00
552 lines
15 KiB
C++
552 lines
15 KiB
C++
// This file is part of meshoptimizer library; see meshoptimizer.h for version/license details
|
|
#include "meshoptimizer.h"
|
|
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
|
|
// This work is based on:
|
|
// John McDonald, Mark Kilgard. Crack-Free Point-Normal Triangles using Adjacent Edge Normals. 2010
|
|
namespace meshopt
|
|
{
|
|
|
|
static unsigned int hashUpdate4(unsigned int h, const unsigned char* key, size_t len)
|
|
{
|
|
// MurmurHash2
|
|
const unsigned int m = 0x5bd1e995;
|
|
const int r = 24;
|
|
|
|
while (len >= 4)
|
|
{
|
|
unsigned int k = *reinterpret_cast<const unsigned int*>(key);
|
|
|
|
k *= m;
|
|
k ^= k >> r;
|
|
k *= m;
|
|
|
|
h *= m;
|
|
h ^= k;
|
|
|
|
key += 4;
|
|
len -= 4;
|
|
}
|
|
|
|
return h;
|
|
}
|
|
|
|
struct VertexHasher
|
|
{
|
|
const unsigned char* vertices;
|
|
size_t vertex_size;
|
|
size_t vertex_stride;
|
|
|
|
size_t hash(unsigned int index) const
|
|
{
|
|
return hashUpdate4(0, vertices + index * vertex_stride, vertex_size);
|
|
}
|
|
|
|
bool equal(unsigned int lhs, unsigned int rhs) const
|
|
{
|
|
return memcmp(vertices + lhs * vertex_stride, vertices + rhs * vertex_stride, vertex_size) == 0;
|
|
}
|
|
};
|
|
|
|
struct VertexStreamHasher
|
|
{
|
|
const meshopt_Stream* streams;
|
|
size_t stream_count;
|
|
|
|
size_t hash(unsigned int index) const
|
|
{
|
|
unsigned int h = 0;
|
|
|
|
for (size_t i = 0; i < stream_count; ++i)
|
|
{
|
|
const meshopt_Stream& s = streams[i];
|
|
const unsigned char* data = static_cast<const unsigned char*>(s.data);
|
|
|
|
h = hashUpdate4(h, data + index * s.stride, s.size);
|
|
}
|
|
|
|
return h;
|
|
}
|
|
|
|
bool equal(unsigned int lhs, unsigned int rhs) const
|
|
{
|
|
for (size_t i = 0; i < stream_count; ++i)
|
|
{
|
|
const meshopt_Stream& s = streams[i];
|
|
const unsigned char* data = static_cast<const unsigned char*>(s.data);
|
|
|
|
if (memcmp(data + lhs * s.stride, data + rhs * s.stride, s.size) != 0)
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
};
|
|
|
|
struct EdgeHasher
|
|
{
|
|
const unsigned int* remap;
|
|
|
|
size_t hash(unsigned long long edge) const
|
|
{
|
|
unsigned int e0 = unsigned(edge >> 32);
|
|
unsigned int e1 = unsigned(edge);
|
|
|
|
unsigned int h1 = remap[e0];
|
|
unsigned int h2 = remap[e1];
|
|
|
|
const unsigned int m = 0x5bd1e995;
|
|
|
|
// MurmurHash64B finalizer
|
|
h1 ^= h2 >> 18;
|
|
h1 *= m;
|
|
h2 ^= h1 >> 22;
|
|
h2 *= m;
|
|
h1 ^= h2 >> 17;
|
|
h1 *= m;
|
|
h2 ^= h1 >> 19;
|
|
h2 *= m;
|
|
|
|
return h2;
|
|
}
|
|
|
|
bool equal(unsigned long long lhs, unsigned long long rhs) const
|
|
{
|
|
unsigned int l0 = unsigned(lhs >> 32);
|
|
unsigned int l1 = unsigned(lhs);
|
|
|
|
unsigned int r0 = unsigned(rhs >> 32);
|
|
unsigned int r1 = unsigned(rhs);
|
|
|
|
return remap[l0] == remap[r0] && remap[l1] == remap[r1];
|
|
}
|
|
};
|
|
|
|
static size_t hashBuckets(size_t count)
|
|
{
|
|
size_t buckets = 1;
|
|
while (buckets < count + count / 4)
|
|
buckets *= 2;
|
|
|
|
return buckets;
|
|
}
|
|
|
|
template <typename T, typename Hash>
|
|
static T* hashLookup(T* table, size_t buckets, const Hash& hash, const T& key, const T& empty)
|
|
{
|
|
assert(buckets > 0);
|
|
assert((buckets & (buckets - 1)) == 0);
|
|
|
|
size_t hashmod = buckets - 1;
|
|
size_t bucket = hash.hash(key) & hashmod;
|
|
|
|
for (size_t probe = 0; probe <= hashmod; ++probe)
|
|
{
|
|
T& item = table[bucket];
|
|
|
|
if (item == empty)
|
|
return &item;
|
|
|
|
if (hash.equal(item, key))
|
|
return &item;
|
|
|
|
// hash collision, quadratic probing
|
|
bucket = (bucket + probe + 1) & hashmod;
|
|
}
|
|
|
|
assert(false && "Hash table is full"); // unreachable
|
|
return 0;
|
|
}
|
|
|
|
static void buildPositionRemap(unsigned int* remap, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, meshopt_Allocator& allocator)
|
|
{
|
|
VertexHasher vertex_hasher = {reinterpret_cast<const unsigned char*>(vertex_positions), 3 * sizeof(float), vertex_positions_stride};
|
|
|
|
size_t vertex_table_size = hashBuckets(vertex_count);
|
|
unsigned int* vertex_table = allocator.allocate<unsigned int>(vertex_table_size);
|
|
memset(vertex_table, -1, vertex_table_size * sizeof(unsigned int));
|
|
|
|
for (size_t i = 0; i < vertex_count; ++i)
|
|
{
|
|
unsigned int index = unsigned(i);
|
|
unsigned int* entry = hashLookup(vertex_table, vertex_table_size, vertex_hasher, index, ~0u);
|
|
|
|
if (*entry == ~0u)
|
|
*entry = index;
|
|
|
|
remap[index] = *entry;
|
|
}
|
|
}
|
|
|
|
} // namespace meshopt
|
|
|
|
size_t meshopt_generateVertexRemap(unsigned int* destination, const unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(indices || index_count == vertex_count);
|
|
assert(index_count % 3 == 0);
|
|
assert(vertex_size > 0 && vertex_size <= 256);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
memset(destination, -1, vertex_count * sizeof(unsigned int));
|
|
|
|
VertexHasher hasher = {static_cast<const unsigned char*>(vertices), vertex_size, vertex_size};
|
|
|
|
size_t table_size = hashBuckets(vertex_count);
|
|
unsigned int* table = allocator.allocate<unsigned int>(table_size);
|
|
memset(table, -1, table_size * sizeof(unsigned int));
|
|
|
|
unsigned int next_vertex = 0;
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
unsigned int index = indices ? indices[i] : unsigned(i);
|
|
assert(index < vertex_count);
|
|
|
|
if (destination[index] == ~0u)
|
|
{
|
|
unsigned int* entry = hashLookup(table, table_size, hasher, index, ~0u);
|
|
|
|
if (*entry == ~0u)
|
|
{
|
|
*entry = index;
|
|
|
|
destination[index] = next_vertex++;
|
|
}
|
|
else
|
|
{
|
|
assert(destination[*entry] != ~0u);
|
|
|
|
destination[index] = destination[*entry];
|
|
}
|
|
}
|
|
}
|
|
|
|
assert(next_vertex <= vertex_count);
|
|
|
|
return next_vertex;
|
|
}
|
|
|
|
size_t meshopt_generateVertexRemapMulti(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, const struct meshopt_Stream* streams, size_t stream_count)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(indices || index_count == vertex_count);
|
|
assert(index_count % 3 == 0);
|
|
assert(stream_count > 0 && stream_count <= 16);
|
|
|
|
for (size_t i = 0; i < stream_count; ++i)
|
|
{
|
|
assert(streams[i].size > 0 && streams[i].size <= 256);
|
|
assert(streams[i].size <= streams[i].stride);
|
|
}
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
memset(destination, -1, vertex_count * sizeof(unsigned int));
|
|
|
|
VertexStreamHasher hasher = {streams, stream_count};
|
|
|
|
size_t table_size = hashBuckets(vertex_count);
|
|
unsigned int* table = allocator.allocate<unsigned int>(table_size);
|
|
memset(table, -1, table_size * sizeof(unsigned int));
|
|
|
|
unsigned int next_vertex = 0;
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
unsigned int index = indices ? indices[i] : unsigned(i);
|
|
assert(index < vertex_count);
|
|
|
|
if (destination[index] == ~0u)
|
|
{
|
|
unsigned int* entry = hashLookup(table, table_size, hasher, index, ~0u);
|
|
|
|
if (*entry == ~0u)
|
|
{
|
|
*entry = index;
|
|
|
|
destination[index] = next_vertex++;
|
|
}
|
|
else
|
|
{
|
|
assert(destination[*entry] != ~0u);
|
|
|
|
destination[index] = destination[*entry];
|
|
}
|
|
}
|
|
}
|
|
|
|
assert(next_vertex <= vertex_count);
|
|
|
|
return next_vertex;
|
|
}
|
|
|
|
void meshopt_remapVertexBuffer(void* destination, const void* vertices, size_t vertex_count, size_t vertex_size, const unsigned int* remap)
|
|
{
|
|
assert(vertex_size > 0 && vertex_size <= 256);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
// support in-place remap
|
|
if (destination == vertices)
|
|
{
|
|
unsigned char* vertices_copy = allocator.allocate<unsigned char>(vertex_count * vertex_size);
|
|
memcpy(vertices_copy, vertices, vertex_count * vertex_size);
|
|
vertices = vertices_copy;
|
|
}
|
|
|
|
for (size_t i = 0; i < vertex_count; ++i)
|
|
{
|
|
if (remap[i] != ~0u)
|
|
{
|
|
assert(remap[i] < vertex_count);
|
|
|
|
memcpy(static_cast<unsigned char*>(destination) + remap[i] * vertex_size, static_cast<const unsigned char*>(vertices) + i * vertex_size, vertex_size);
|
|
}
|
|
}
|
|
}
|
|
|
|
void meshopt_remapIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const unsigned int* remap)
|
|
{
|
|
assert(index_count % 3 == 0);
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
unsigned int index = indices ? indices[i] : unsigned(i);
|
|
assert(remap[index] != ~0u);
|
|
|
|
destination[i] = remap[index];
|
|
}
|
|
}
|
|
|
|
void meshopt_generateShadowIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size, size_t vertex_stride)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(indices);
|
|
assert(index_count % 3 == 0);
|
|
assert(vertex_size > 0 && vertex_size <= 256);
|
|
assert(vertex_size <= vertex_stride);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
unsigned int* remap = allocator.allocate<unsigned int>(vertex_count);
|
|
memset(remap, -1, vertex_count * sizeof(unsigned int));
|
|
|
|
VertexHasher hasher = {static_cast<const unsigned char*>(vertices), vertex_size, vertex_stride};
|
|
|
|
size_t table_size = hashBuckets(vertex_count);
|
|
unsigned int* table = allocator.allocate<unsigned int>(table_size);
|
|
memset(table, -1, table_size * sizeof(unsigned int));
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
unsigned int index = indices[i];
|
|
assert(index < vertex_count);
|
|
|
|
if (remap[index] == ~0u)
|
|
{
|
|
unsigned int* entry = hashLookup(table, table_size, hasher, index, ~0u);
|
|
|
|
if (*entry == ~0u)
|
|
*entry = index;
|
|
|
|
remap[index] = *entry;
|
|
}
|
|
|
|
destination[i] = remap[index];
|
|
}
|
|
}
|
|
|
|
void meshopt_generateShadowIndexBufferMulti(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, const struct meshopt_Stream* streams, size_t stream_count)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(indices);
|
|
assert(index_count % 3 == 0);
|
|
assert(stream_count > 0 && stream_count <= 16);
|
|
|
|
for (size_t i = 0; i < stream_count; ++i)
|
|
{
|
|
assert(streams[i].size > 0 && streams[i].size <= 256);
|
|
assert(streams[i].size <= streams[i].stride);
|
|
}
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
unsigned int* remap = allocator.allocate<unsigned int>(vertex_count);
|
|
memset(remap, -1, vertex_count * sizeof(unsigned int));
|
|
|
|
VertexStreamHasher hasher = {streams, stream_count};
|
|
|
|
size_t table_size = hashBuckets(vertex_count);
|
|
unsigned int* table = allocator.allocate<unsigned int>(table_size);
|
|
memset(table, -1, table_size * sizeof(unsigned int));
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
unsigned int index = indices[i];
|
|
assert(index < vertex_count);
|
|
|
|
if (remap[index] == ~0u)
|
|
{
|
|
unsigned int* entry = hashLookup(table, table_size, hasher, index, ~0u);
|
|
|
|
if (*entry == ~0u)
|
|
*entry = index;
|
|
|
|
remap[index] = *entry;
|
|
}
|
|
|
|
destination[i] = remap[index];
|
|
}
|
|
}
|
|
|
|
void meshopt_generateAdjacencyIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(index_count % 3 == 0);
|
|
assert(vertex_positions_stride > 0 && vertex_positions_stride <= 256);
|
|
assert(vertex_positions_stride % sizeof(float) == 0);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
static const int next[4] = {1, 2, 0, 1};
|
|
|
|
// build position remap: for each vertex, which other (canonical) vertex does it map to?
|
|
unsigned int* remap = allocator.allocate<unsigned int>(vertex_count);
|
|
buildPositionRemap(remap, vertex_positions, vertex_count, vertex_positions_stride, allocator);
|
|
|
|
// build edge set; this stores all triangle edges but we can look these up by any other wedge
|
|
EdgeHasher edge_hasher = {remap};
|
|
|
|
size_t edge_table_size = hashBuckets(index_count);
|
|
unsigned long long* edge_table = allocator.allocate<unsigned long long>(edge_table_size);
|
|
unsigned int* edge_vertex_table = allocator.allocate<unsigned int>(edge_table_size);
|
|
|
|
memset(edge_table, -1, edge_table_size * sizeof(unsigned long long));
|
|
memset(edge_vertex_table, -1, edge_table_size * sizeof(unsigned int));
|
|
|
|
for (size_t i = 0; i < index_count; i += 3)
|
|
{
|
|
for (int e = 0; e < 3; ++e)
|
|
{
|
|
unsigned int i0 = indices[i + e];
|
|
unsigned int i1 = indices[i + next[e]];
|
|
unsigned int i2 = indices[i + next[e + 1]];
|
|
assert(i0 < vertex_count && i1 < vertex_count && i2 < vertex_count);
|
|
|
|
unsigned long long edge = ((unsigned long long)i0 << 32) | i1;
|
|
unsigned long long* entry = hashLookup(edge_table, edge_table_size, edge_hasher, edge, ~0ull);
|
|
|
|
if (*entry == ~0ull)
|
|
{
|
|
*entry = edge;
|
|
|
|
// store vertex opposite to the edge
|
|
edge_vertex_table[entry - edge_table] = i2;
|
|
}
|
|
}
|
|
}
|
|
|
|
// build resulting index buffer: 6 indices for each input triangle
|
|
for (size_t i = 0; i < index_count; i += 3)
|
|
{
|
|
unsigned int patch[6];
|
|
|
|
for (int e = 0; e < 3; ++e)
|
|
{
|
|
unsigned int i0 = indices[i + e];
|
|
unsigned int i1 = indices[i + next[e]];
|
|
assert(i0 < vertex_count && i1 < vertex_count);
|
|
|
|
// note: this refers to the opposite edge!
|
|
unsigned long long edge = ((unsigned long long)i1 << 32) | i0;
|
|
unsigned long long* oppe = hashLookup(edge_table, edge_table_size, edge_hasher, edge, ~0ull);
|
|
|
|
patch[e * 2 + 0] = i0;
|
|
patch[e * 2 + 1] = (*oppe == ~0ull) ? i0 : edge_vertex_table[oppe - edge_table];
|
|
}
|
|
|
|
memcpy(destination + i * 2, patch, sizeof(patch));
|
|
}
|
|
}
|
|
|
|
void meshopt_generateTessellationIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(index_count % 3 == 0);
|
|
assert(vertex_positions_stride > 0 && vertex_positions_stride <= 256);
|
|
assert(vertex_positions_stride % sizeof(float) == 0);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
static const int next[3] = {1, 2, 0};
|
|
|
|
// build position remap: for each vertex, which other (canonical) vertex does it map to?
|
|
unsigned int* remap = allocator.allocate<unsigned int>(vertex_count);
|
|
buildPositionRemap(remap, vertex_positions, vertex_count, vertex_positions_stride, allocator);
|
|
|
|
// build edge set; this stores all triangle edges but we can look these up by any other wedge
|
|
EdgeHasher edge_hasher = {remap};
|
|
|
|
size_t edge_table_size = hashBuckets(index_count);
|
|
unsigned long long* edge_table = allocator.allocate<unsigned long long>(edge_table_size);
|
|
memset(edge_table, -1, edge_table_size * sizeof(unsigned long long));
|
|
|
|
for (size_t i = 0; i < index_count; i += 3)
|
|
{
|
|
for (int e = 0; e < 3; ++e)
|
|
{
|
|
unsigned int i0 = indices[i + e];
|
|
unsigned int i1 = indices[i + next[e]];
|
|
assert(i0 < vertex_count && i1 < vertex_count);
|
|
|
|
unsigned long long edge = ((unsigned long long)i0 << 32) | i1;
|
|
unsigned long long* entry = hashLookup(edge_table, edge_table_size, edge_hasher, edge, ~0ull);
|
|
|
|
if (*entry == ~0ull)
|
|
*entry = edge;
|
|
}
|
|
}
|
|
|
|
// build resulting index buffer: 12 indices for each input triangle
|
|
for (size_t i = 0; i < index_count; i += 3)
|
|
{
|
|
unsigned int patch[12];
|
|
|
|
for (int e = 0; e < 3; ++e)
|
|
{
|
|
unsigned int i0 = indices[i + e];
|
|
unsigned int i1 = indices[i + next[e]];
|
|
assert(i0 < vertex_count && i1 < vertex_count);
|
|
|
|
// note: this refers to the opposite edge!
|
|
unsigned long long edge = ((unsigned long long)i1 << 32) | i0;
|
|
unsigned long long oppe = *hashLookup(edge_table, edge_table_size, edge_hasher, edge, ~0ull);
|
|
|
|
// use the same edge if opposite edge doesn't exist (border)
|
|
oppe = (oppe == ~0ull) ? edge : oppe;
|
|
|
|
// triangle index (0, 1, 2)
|
|
patch[e] = i0;
|
|
|
|
// opposite edge (3, 4; 5, 6; 7, 8)
|
|
patch[3 + e * 2 + 0] = unsigned(oppe);
|
|
patch[3 + e * 2 + 1] = unsigned(oppe >> 32);
|
|
|
|
// dominant vertex (9, 10, 11)
|
|
patch[9 + e] = remap[i0];
|
|
}
|
|
|
|
memcpy(destination + i * 4, patch, sizeof(patch));
|
|
}
|
|
}
|