godot/thirdparty/meshoptimizer/indexgenerator.cpp
reduz 77a045e902 Rework Mesh handling on scene importing.
-Reworked how meshes are treated by importer by using EditorSceneImporterMesh and EditorSceneImporterMeshNode. Instead of Mesh and MeshInstance, this allows more efficient processing of meshes before they are actually registered in the RenderingServer.
-Integrated MeshOptimizer
-Reworked internals of SurfaceTool to use arrays, making it more performant and easy to run optimizatons on.
2020-12-13 21:29:51 -03:00

348 lines
8.2 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>
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;
}
};
static size_t hashBuckets(size_t count)
{
size_t buckets = 1;
while (buckets < count)
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;
}
} // 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];
}
}