mirror of
https://github.com/godotengine/godot.git
synced 2024-12-27 11:24:59 +08:00
c5f73a1783
Note: this change completely overwrites the meshoptimizer library source (from git SHA c21d3be6ddf627f8ca852ba4b6db9903b0557858) without including any patches; a distance error metric patch is still needed and will be reapplied in the next commit. The changes elsewhere are due to a signature change for meshopt_simplifyWithAttributes.
473 lines
14 KiB
C++
473 lines
14 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:
|
|
// Tom Forsyth. Linear-Speed Vertex Cache Optimisation. 2006
|
|
// Pedro Sander, Diego Nehab and Joshua Barczak. Fast Triangle Reordering for Vertex Locality and Reduced Overdraw. 2007
|
|
namespace meshopt
|
|
{
|
|
|
|
const size_t kCacheSizeMax = 16;
|
|
const size_t kValenceMax = 8;
|
|
|
|
struct VertexScoreTable
|
|
{
|
|
float cache[1 + kCacheSizeMax];
|
|
float live[1 + kValenceMax];
|
|
};
|
|
|
|
// Tuned to minimize the ACMR of a GPU that has a cache profile similar to NVidia and AMD
|
|
static const VertexScoreTable kVertexScoreTable = {
|
|
{0.f, 0.779f, 0.791f, 0.789f, 0.981f, 0.843f, 0.726f, 0.847f, 0.882f, 0.867f, 0.799f, 0.642f, 0.613f, 0.600f, 0.568f, 0.372f, 0.234f},
|
|
{0.f, 0.995f, 0.713f, 0.450f, 0.404f, 0.059f, 0.005f, 0.147f, 0.006f},
|
|
};
|
|
|
|
// Tuned to minimize the encoded index buffer size
|
|
static const VertexScoreTable kVertexScoreTableStrip = {
|
|
{0.f, 1.000f, 1.000f, 1.000f, 0.453f, 0.561f, 0.490f, 0.459f, 0.179f, 0.526f, 0.000f, 0.227f, 0.184f, 0.490f, 0.112f, 0.050f, 0.131f},
|
|
{0.f, 0.956f, 0.786f, 0.577f, 0.558f, 0.618f, 0.549f, 0.499f, 0.489f},
|
|
};
|
|
|
|
struct TriangleAdjacency
|
|
{
|
|
unsigned int* counts;
|
|
unsigned int* offsets;
|
|
unsigned int* data;
|
|
};
|
|
|
|
static void buildTriangleAdjacency(TriangleAdjacency& adjacency, const unsigned int* indices, size_t index_count, size_t vertex_count, meshopt_Allocator& allocator)
|
|
{
|
|
size_t face_count = index_count / 3;
|
|
|
|
// allocate arrays
|
|
adjacency.counts = allocator.allocate<unsigned int>(vertex_count);
|
|
adjacency.offsets = allocator.allocate<unsigned int>(vertex_count);
|
|
adjacency.data = allocator.allocate<unsigned int>(index_count);
|
|
|
|
// fill triangle counts
|
|
memset(adjacency.counts, 0, vertex_count * sizeof(unsigned int));
|
|
|
|
for (size_t i = 0; i < index_count; ++i)
|
|
{
|
|
assert(indices[i] < vertex_count);
|
|
|
|
adjacency.counts[indices[i]]++;
|
|
}
|
|
|
|
// fill offset table
|
|
unsigned int offset = 0;
|
|
|
|
for (size_t i = 0; i < vertex_count; ++i)
|
|
{
|
|
adjacency.offsets[i] = offset;
|
|
offset += adjacency.counts[i];
|
|
}
|
|
|
|
assert(offset == index_count);
|
|
|
|
// fill triangle data
|
|
for (size_t i = 0; i < face_count; ++i)
|
|
{
|
|
unsigned int a = indices[i * 3 + 0], b = indices[i * 3 + 1], c = indices[i * 3 + 2];
|
|
|
|
adjacency.data[adjacency.offsets[a]++] = unsigned(i);
|
|
adjacency.data[adjacency.offsets[b]++] = unsigned(i);
|
|
adjacency.data[adjacency.offsets[c]++] = unsigned(i);
|
|
}
|
|
|
|
// fix offsets that have been disturbed by the previous pass
|
|
for (size_t i = 0; i < vertex_count; ++i)
|
|
{
|
|
assert(adjacency.offsets[i] >= adjacency.counts[i]);
|
|
|
|
adjacency.offsets[i] -= adjacency.counts[i];
|
|
}
|
|
}
|
|
|
|
static unsigned int getNextVertexDeadEnd(const unsigned int* dead_end, unsigned int& dead_end_top, unsigned int& input_cursor, const unsigned int* live_triangles, size_t vertex_count)
|
|
{
|
|
// check dead-end stack
|
|
while (dead_end_top)
|
|
{
|
|
unsigned int vertex = dead_end[--dead_end_top];
|
|
|
|
if (live_triangles[vertex] > 0)
|
|
return vertex;
|
|
}
|
|
|
|
// input order
|
|
while (input_cursor < vertex_count)
|
|
{
|
|
if (live_triangles[input_cursor] > 0)
|
|
return input_cursor;
|
|
|
|
++input_cursor;
|
|
}
|
|
|
|
return ~0u;
|
|
}
|
|
|
|
static unsigned int getNextVertexNeighbor(const unsigned int* next_candidates_begin, const unsigned int* next_candidates_end, const unsigned int* live_triangles, const unsigned int* cache_timestamps, unsigned int timestamp, unsigned int cache_size)
|
|
{
|
|
unsigned int best_candidate = ~0u;
|
|
int best_priority = -1;
|
|
|
|
for (const unsigned int* next_candidate = next_candidates_begin; next_candidate != next_candidates_end; ++next_candidate)
|
|
{
|
|
unsigned int vertex = *next_candidate;
|
|
|
|
// otherwise we don't need to process it
|
|
if (live_triangles[vertex] > 0)
|
|
{
|
|
int priority = 0;
|
|
|
|
// will it be in cache after fanning?
|
|
if (2 * live_triangles[vertex] + timestamp - cache_timestamps[vertex] <= cache_size)
|
|
{
|
|
priority = timestamp - cache_timestamps[vertex]; // position in cache
|
|
}
|
|
|
|
if (priority > best_priority)
|
|
{
|
|
best_candidate = vertex;
|
|
best_priority = priority;
|
|
}
|
|
}
|
|
}
|
|
|
|
return best_candidate;
|
|
}
|
|
|
|
static float vertexScore(const VertexScoreTable* table, int cache_position, unsigned int live_triangles)
|
|
{
|
|
assert(cache_position >= -1 && cache_position < int(kCacheSizeMax));
|
|
|
|
unsigned int live_triangles_clamped = live_triangles < kValenceMax ? live_triangles : kValenceMax;
|
|
|
|
return table->cache[1 + cache_position] + table->live[live_triangles_clamped];
|
|
}
|
|
|
|
static unsigned int getNextTriangleDeadEnd(unsigned int& input_cursor, const unsigned char* emitted_flags, size_t face_count)
|
|
{
|
|
// input order
|
|
while (input_cursor < face_count)
|
|
{
|
|
if (!emitted_flags[input_cursor])
|
|
return input_cursor;
|
|
|
|
++input_cursor;
|
|
}
|
|
|
|
return ~0u;
|
|
}
|
|
|
|
} // namespace meshopt
|
|
|
|
void meshopt_optimizeVertexCacheTable(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, const meshopt::VertexScoreTable* table)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(index_count % 3 == 0);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
// guard for empty meshes
|
|
if (index_count == 0 || vertex_count == 0)
|
|
return;
|
|
|
|
// support in-place optimization
|
|
if (destination == indices)
|
|
{
|
|
unsigned int* indices_copy = allocator.allocate<unsigned int>(index_count);
|
|
memcpy(indices_copy, indices, index_count * sizeof(unsigned int));
|
|
indices = indices_copy;
|
|
}
|
|
|
|
unsigned int cache_size = 16;
|
|
assert(cache_size <= kCacheSizeMax);
|
|
|
|
size_t face_count = index_count / 3;
|
|
|
|
// build adjacency information
|
|
TriangleAdjacency adjacency = {};
|
|
buildTriangleAdjacency(adjacency, indices, index_count, vertex_count, allocator);
|
|
|
|
// live triangle counts
|
|
unsigned int* live_triangles = allocator.allocate<unsigned int>(vertex_count);
|
|
memcpy(live_triangles, adjacency.counts, vertex_count * sizeof(unsigned int));
|
|
|
|
// emitted flags
|
|
unsigned char* emitted_flags = allocator.allocate<unsigned char>(face_count);
|
|
memset(emitted_flags, 0, face_count);
|
|
|
|
// compute initial vertex scores
|
|
float* vertex_scores = allocator.allocate<float>(vertex_count);
|
|
|
|
for (size_t i = 0; i < vertex_count; ++i)
|
|
vertex_scores[i] = vertexScore(table, -1, live_triangles[i]);
|
|
|
|
// compute triangle scores
|
|
float* triangle_scores = allocator.allocate<float>(face_count);
|
|
|
|
for (size_t i = 0; i < face_count; ++i)
|
|
{
|
|
unsigned int a = indices[i * 3 + 0];
|
|
unsigned int b = indices[i * 3 + 1];
|
|
unsigned int c = indices[i * 3 + 2];
|
|
|
|
triangle_scores[i] = vertex_scores[a] + vertex_scores[b] + vertex_scores[c];
|
|
}
|
|
|
|
unsigned int cache_holder[2 * (kCacheSizeMax + 4)];
|
|
unsigned int* cache = cache_holder;
|
|
unsigned int* cache_new = cache_holder + kCacheSizeMax + 4;
|
|
size_t cache_count = 0;
|
|
|
|
unsigned int current_triangle = 0;
|
|
unsigned int input_cursor = 1;
|
|
|
|
unsigned int output_triangle = 0;
|
|
|
|
while (current_triangle != ~0u)
|
|
{
|
|
assert(output_triangle < face_count);
|
|
|
|
unsigned int a = indices[current_triangle * 3 + 0];
|
|
unsigned int b = indices[current_triangle * 3 + 1];
|
|
unsigned int c = indices[current_triangle * 3 + 2];
|
|
|
|
// output indices
|
|
destination[output_triangle * 3 + 0] = a;
|
|
destination[output_triangle * 3 + 1] = b;
|
|
destination[output_triangle * 3 + 2] = c;
|
|
output_triangle++;
|
|
|
|
// update emitted flags
|
|
emitted_flags[current_triangle] = true;
|
|
triangle_scores[current_triangle] = 0;
|
|
|
|
// new triangle
|
|
size_t cache_write = 0;
|
|
cache_new[cache_write++] = a;
|
|
cache_new[cache_write++] = b;
|
|
cache_new[cache_write++] = c;
|
|
|
|
// old triangles
|
|
for (size_t i = 0; i < cache_count; ++i)
|
|
{
|
|
unsigned int index = cache[i];
|
|
|
|
cache_new[cache_write] = index;
|
|
cache_write += (index != a && index != b && index != c);
|
|
}
|
|
|
|
unsigned int* cache_temp = cache;
|
|
cache = cache_new, cache_new = cache_temp;
|
|
cache_count = cache_write > cache_size ? cache_size : cache_write;
|
|
|
|
// update live triangle counts
|
|
live_triangles[a]--;
|
|
live_triangles[b]--;
|
|
live_triangles[c]--;
|
|
|
|
// remove emitted triangle from adjacency data
|
|
// this makes sure that we spend less time traversing these lists on subsequent iterations
|
|
for (size_t k = 0; k < 3; ++k)
|
|
{
|
|
unsigned int index = indices[current_triangle * 3 + k];
|
|
|
|
unsigned int* neighbors = &adjacency.data[0] + adjacency.offsets[index];
|
|
size_t neighbors_size = adjacency.counts[index];
|
|
|
|
for (size_t i = 0; i < neighbors_size; ++i)
|
|
{
|
|
unsigned int tri = neighbors[i];
|
|
|
|
if (tri == current_triangle)
|
|
{
|
|
neighbors[i] = neighbors[neighbors_size - 1];
|
|
adjacency.counts[index]--;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned int best_triangle = ~0u;
|
|
float best_score = 0;
|
|
|
|
// update cache positions, vertex scores and triangle scores, and find next best triangle
|
|
for (size_t i = 0; i < cache_write; ++i)
|
|
{
|
|
unsigned int index = cache[i];
|
|
|
|
// no need to update scores if we are never going to use this vertex
|
|
if (adjacency.counts[index] == 0)
|
|
continue;
|
|
|
|
int cache_position = i >= cache_size ? -1 : int(i);
|
|
|
|
// update vertex score
|
|
float score = vertexScore(table, cache_position, live_triangles[index]);
|
|
float score_diff = score - vertex_scores[index];
|
|
|
|
vertex_scores[index] = score;
|
|
|
|
// update scores of vertex triangles
|
|
const unsigned int* neighbors_begin = &adjacency.data[0] + adjacency.offsets[index];
|
|
const unsigned int* neighbors_end = neighbors_begin + adjacency.counts[index];
|
|
|
|
for (const unsigned int* it = neighbors_begin; it != neighbors_end; ++it)
|
|
{
|
|
unsigned int tri = *it;
|
|
assert(!emitted_flags[tri]);
|
|
|
|
float tri_score = triangle_scores[tri] + score_diff;
|
|
assert(tri_score > 0);
|
|
|
|
best_triangle = best_score < tri_score ? tri : best_triangle;
|
|
best_score = best_score < tri_score ? tri_score : best_score;
|
|
|
|
triangle_scores[tri] = tri_score;
|
|
}
|
|
}
|
|
|
|
// step through input triangles in order if we hit a dead-end
|
|
current_triangle = best_triangle;
|
|
|
|
if (current_triangle == ~0u)
|
|
{
|
|
current_triangle = getNextTriangleDeadEnd(input_cursor, &emitted_flags[0], face_count);
|
|
}
|
|
}
|
|
|
|
assert(input_cursor == face_count);
|
|
assert(output_triangle == face_count);
|
|
}
|
|
|
|
void meshopt_optimizeVertexCache(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count)
|
|
{
|
|
meshopt_optimizeVertexCacheTable(destination, indices, index_count, vertex_count, &meshopt::kVertexScoreTable);
|
|
}
|
|
|
|
void meshopt_optimizeVertexCacheStrip(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count)
|
|
{
|
|
meshopt_optimizeVertexCacheTable(destination, indices, index_count, vertex_count, &meshopt::kVertexScoreTableStrip);
|
|
}
|
|
|
|
void meshopt_optimizeVertexCacheFifo(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, unsigned int cache_size)
|
|
{
|
|
using namespace meshopt;
|
|
|
|
assert(index_count % 3 == 0);
|
|
assert(cache_size >= 3);
|
|
|
|
meshopt_Allocator allocator;
|
|
|
|
// guard for empty meshes
|
|
if (index_count == 0 || vertex_count == 0)
|
|
return;
|
|
|
|
// support in-place optimization
|
|
if (destination == indices)
|
|
{
|
|
unsigned int* indices_copy = allocator.allocate<unsigned int>(index_count);
|
|
memcpy(indices_copy, indices, index_count * sizeof(unsigned int));
|
|
indices = indices_copy;
|
|
}
|
|
|
|
size_t face_count = index_count / 3;
|
|
|
|
// build adjacency information
|
|
TriangleAdjacency adjacency = {};
|
|
buildTriangleAdjacency(adjacency, indices, index_count, vertex_count, allocator);
|
|
|
|
// live triangle counts
|
|
unsigned int* live_triangles = allocator.allocate<unsigned int>(vertex_count);
|
|
memcpy(live_triangles, adjacency.counts, vertex_count * sizeof(unsigned int));
|
|
|
|
// cache time stamps
|
|
unsigned int* cache_timestamps = allocator.allocate<unsigned int>(vertex_count);
|
|
memset(cache_timestamps, 0, vertex_count * sizeof(unsigned int));
|
|
|
|
// dead-end stack
|
|
unsigned int* dead_end = allocator.allocate<unsigned int>(index_count);
|
|
unsigned int dead_end_top = 0;
|
|
|
|
// emitted flags
|
|
unsigned char* emitted_flags = allocator.allocate<unsigned char>(face_count);
|
|
memset(emitted_flags, 0, face_count);
|
|
|
|
unsigned int current_vertex = 0;
|
|
|
|
unsigned int timestamp = cache_size + 1;
|
|
unsigned int input_cursor = 1; // vertex to restart from in case of dead-end
|
|
|
|
unsigned int output_triangle = 0;
|
|
|
|
while (current_vertex != ~0u)
|
|
{
|
|
const unsigned int* next_candidates_begin = &dead_end[0] + dead_end_top;
|
|
|
|
// emit all vertex neighbors
|
|
const unsigned int* neighbors_begin = &adjacency.data[0] + adjacency.offsets[current_vertex];
|
|
const unsigned int* neighbors_end = neighbors_begin + adjacency.counts[current_vertex];
|
|
|
|
for (const unsigned int* it = neighbors_begin; it != neighbors_end; ++it)
|
|
{
|
|
unsigned int triangle = *it;
|
|
|
|
if (!emitted_flags[triangle])
|
|
{
|
|
unsigned int a = indices[triangle * 3 + 0], b = indices[triangle * 3 + 1], c = indices[triangle * 3 + 2];
|
|
|
|
// output indices
|
|
destination[output_triangle * 3 + 0] = a;
|
|
destination[output_triangle * 3 + 1] = b;
|
|
destination[output_triangle * 3 + 2] = c;
|
|
output_triangle++;
|
|
|
|
// update dead-end stack
|
|
dead_end[dead_end_top + 0] = a;
|
|
dead_end[dead_end_top + 1] = b;
|
|
dead_end[dead_end_top + 2] = c;
|
|
dead_end_top += 3;
|
|
|
|
// update live triangle counts
|
|
live_triangles[a]--;
|
|
live_triangles[b]--;
|
|
live_triangles[c]--;
|
|
|
|
// update cache info
|
|
// if vertex is not in cache, put it in cache
|
|
if (timestamp - cache_timestamps[a] > cache_size)
|
|
cache_timestamps[a] = timestamp++;
|
|
|
|
if (timestamp - cache_timestamps[b] > cache_size)
|
|
cache_timestamps[b] = timestamp++;
|
|
|
|
if (timestamp - cache_timestamps[c] > cache_size)
|
|
cache_timestamps[c] = timestamp++;
|
|
|
|
// update emitted flags
|
|
emitted_flags[triangle] = true;
|
|
}
|
|
}
|
|
|
|
// next candidates are the ones we pushed to dead-end stack just now
|
|
const unsigned int* next_candidates_end = &dead_end[0] + dead_end_top;
|
|
|
|
// get next vertex
|
|
current_vertex = getNextVertexNeighbor(next_candidates_begin, next_candidates_end, &live_triangles[0], &cache_timestamps[0], timestamp, cache_size);
|
|
|
|
if (current_vertex == ~0u)
|
|
{
|
|
current_vertex = getNextVertexDeadEnd(&dead_end[0], dead_end_top, input_cursor, &live_triangles[0], vertex_count);
|
|
}
|
|
}
|
|
|
|
assert(output_triangle == face_count);
|
|
}
|