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Optimize lightmapper using triangle clusters on the acceleration structure.

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Add an additional layer of indirection to the grid used by the lightmapper to store fixed-size triangle clusters. Greatly speeds up baking times on scenes with high triangle density, as the clusters will help to avoid unnecessary checks when the triangle density is high on the scene.
This commit is contained in:
Dario
2023-10-13 11:39:48 -03:00
parent 325cc0178e
commit 47214ea9f5
4 changed files with 292 additions and 79 deletions
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174
modules/lightmapper_rd/lightmapper_rd.cpp
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@@ -124,7 +124,7 @@ void LightmapperRD::add_probe(const Vector3 &p_position) {
probe_positions.push_back(probe);
}
void LightmapperRD::_plot_triangle_into_triangle_index_list(int p_size, const Vector3i &p_ofs, const AABB &p_bounds, const Vector3 p_points[3], uint32_t p_triangle_index, LocalVector<TriangleSort> &triangles, uint32_t p_grid_size) {
void LightmapperRD::_plot_triangle_into_triangle_index_list(int p_size, const Vector3i &p_ofs, const AABB &p_bounds, const Vector3 p_points[3], uint32_t p_triangle_index, LocalVector<TriangleSort> &p_triangles_sort, uint32_t p_grid_size) {
int half_size = p_size / 2;
for (int i = 0; i < 8; i++) {
@@ -159,13 +159,69 @@ void LightmapperRD::_plot_triangle_into_triangle_index_list(int p_size, const Ve
TriangleSort ts;
ts.cell_index = n.x + (n.y * p_grid_size) + (n.z * p_grid_size * p_grid_size);
ts.triangle_index = p_triangle_index;
triangles.push_back(ts);
ts.triangle_aabb.position = p_points[0];
ts.triangle_aabb.size = Vector3();
ts.triangle_aabb.expand_to(p_points[1]);
ts.triangle_aabb.expand_to(p_points[2]);
p_triangles_sort.push_back(ts);
} else {
_plot_triangle_into_triangle_index_list(half_size, n, aabb, p_points, p_triangle_index, triangles, p_grid_size);
_plot_triangle_into_triangle_index_list(half_size, n, aabb, p_points, p_triangle_index, p_triangles_sort, p_grid_size);
}
}
}
void LightmapperRD::_sort_triangle_clusters(uint32_t p_cluster_size, uint32_t p_cluster_index, uint32_t p_index_start, uint32_t p_count, LocalVector<TriangleSort> &p_triangle_sort, LocalVector<ClusterAABB> &p_cluster_aabb) {
if (p_count == 0) {
return;
}
// Compute AABB for all triangles in the range.
SortArray<TriangleSort, TriangleSortAxis<0>> triangle_sorter_x;
SortArray<TriangleSort, TriangleSortAxis<1>> triangle_sorter_y;
SortArray<TriangleSort, TriangleSortAxis<2>> triangle_sorter_z;
AABB cluster_aabb = p_triangle_sort[p_index_start].triangle_aabb;
for (uint32_t i = 1; i < p_count; i++) {
cluster_aabb.merge_with(p_triangle_sort[p_index_start + i].triangle_aabb);
}
if (p_count > p_cluster_size) {
int longest_axis_index = cluster_aabb.get_longest_axis_index();
switch (longest_axis_index) {
case 0:
triangle_sorter_x.sort(&p_triangle_sort[p_index_start], p_count);
break;
case 1:
triangle_sorter_y.sort(&p_triangle_sort[p_index_start], p_count);
break;
case 2:
triangle_sorter_z.sort(&p_triangle_sort[p_index_start], p_count);
break;
default:
DEV_ASSERT(false && "Invalid axis returned by AABB.");
break;
}
uint32_t left_cluster_count = next_power_of_2(p_count / 2);
left_cluster_count = MAX(left_cluster_count, p_cluster_size);
left_cluster_count = MIN(left_cluster_count, p_count);
_sort_triangle_clusters(p_cluster_size, p_cluster_index, p_index_start, left_cluster_count, p_triangle_sort, p_cluster_aabb);
if (left_cluster_count < p_count) {
uint32_t cluster_index_right = p_cluster_index + (left_cluster_count / p_cluster_size);
_sort_triangle_clusters(p_cluster_size, cluster_index_right, p_index_start + left_cluster_count, p_count - left_cluster_count, p_triangle_sort, p_cluster_aabb);
}
} else {
ClusterAABB &aabb = p_cluster_aabb[p_cluster_index];
Vector3 aabb_end = cluster_aabb.get_end();
aabb.min_bounds[0] = cluster_aabb.position.x;
aabb.min_bounds[1] = cluster_aabb.position.y;
aabb.min_bounds[2] = cluster_aabb.position.z;
aabb.max_bounds[0] = aabb_end.x;
aabb.max_bounds[1] = aabb_end.y;
aabb.max_bounds[2] = aabb_end.z;
}
}
Lightmapper::BakeError LightmapperRD::_blit_meshes_into_atlas(int p_max_texture_size, Vector<Ref<Image>> &albedo_images, Vector<Ref<Image>> &emission_images, AABB &bounds, Size2i &atlas_size, int &atlas_slices, BakeStepFunc p_step_function, void *p_bake_userdata) {
Vector<Size2i> sizes;
@@ -281,7 +337,7 @@ Lightmapper::BakeError LightmapperRD::_blit_meshes_into_atlas(int p_max_texture_
return BAKE_OK;
}
void LightmapperRD::_create_acceleration_structures(RenderingDevice *rd, Size2i atlas_size, int atlas_slices, AABB &bounds, int grid_size, Vector<Probe> &p_probe_positions, GenerateProbes p_generate_probes, Vector<int> &slice_triangle_count, Vector<int> &slice_seam_count, RID &vertex_buffer, RID &triangle_buffer, RID &lights_buffer, RID &triangle_cell_indices_buffer, RID &probe_positions_buffer, RID &grid_texture, RID &seams_buffer, BakeStepFunc p_step_function, void *p_bake_userdata) {
void LightmapperRD::_create_acceleration_structures(RenderingDevice *rd, Size2i atlas_size, int atlas_slices, AABB &bounds, int grid_size, uint32_t p_cluster_size, Vector<Probe> &p_probe_positions, GenerateProbes p_generate_probes, Vector<int> &slice_triangle_count, Vector<int> &slice_seam_count, RID &vertex_buffer, RID &triangle_buffer, RID &lights_buffer, RID &r_triangle_indices_buffer, RID &r_cluster_indices_buffer, RID &r_cluster_aabbs_buffer, RID &probe_positions_buffer, RID &grid_texture, RID &seams_buffer, BakeStepFunc p_step_function, void *p_bake_userdata) {
HashMap<Vertex, uint32_t, VertexHash> vertex_map;
//fill triangles array and vertex array
@@ -433,31 +489,70 @@ void LightmapperRD::_create_acceleration_structures(RenderingDevice *rd, Size2i
//sort it
triangle_sort.sort();
LocalVector<uint32_t> cluster_indices;
LocalVector<ClusterAABB> cluster_aabbs;
Vector<uint32_t> triangle_indices;
triangle_indices.resize(triangle_sort.size());
Vector<uint32_t> grid_indices;
grid_indices.resize(grid_size * grid_size * grid_size * 2);
memset(grid_indices.ptrw(), 0, grid_indices.size() * sizeof(uint32_t));
Vector<bool> solid;
solid.resize(grid_size * grid_size * grid_size);
memset(solid.ptrw(), 0, solid.size() * sizeof(bool));
{
uint32_t *tiw = triangle_indices.ptrw();
// Fill grid with cell indices.
uint32_t last_cell = 0xFFFFFFFF;
uint32_t *giw = grid_indices.ptrw();
bool *solidw = solid.ptrw();
uint32_t cluster_count = 0;
uint32_t solid_cell_count = 0;
for (uint32_t i = 0; i < triangle_sort.size(); i++) {
uint32_t cell = triangle_sort[i].cell_index;
if (cell != last_cell) {
//cell changed, update pointer to indices
giw[cell * 2 + 1] = i;
solidw[cell] = true;
giw[cell * 2 + 1] = solid_cell_count;
solid_cell_count++;
}
tiw[i] = triangle_sort[i].triangle_index;
giw[cell * 2]++; //update counter
if ((giw[cell * 2] % p_cluster_size) == 0) {
// Add an extra cluster every time the triangle counter reaches a multiple of the cluster size.
cluster_count++;
}
giw[cell * 2]++;
last_cell = cell;
}
// Build fixed-size triangle clusters for all the cells to speed up the traversal. A cell can hold multiple clusters that each contain a fixed
// amount of triangles and an AABB. The tracer will check against the AABBs first to know whether it needs to visit the cell's triangles.
//
// The building algorithm will divide the triangles recursively contained inside each cell, sorting by the longest axis of the AABB on each step.
//
// - If the amount of triangles is less or equal to the cluster size, the AABB will be stored and the algorithm stops.
//
// - The division by two is increased to the next power of two of half the amount of triangles (with cluster size as the minimum value) to
// ensure the first half always fills the cluster.
cluster_indices.resize(solid_cell_count * 2);
cluster_aabbs.resize(cluster_count);
uint32_t i = 0;
uint32_t cluster_index = 0;
uint32_t solid_cell_index = 0;
uint32_t *tiw = triangle_indices.ptrw();
while (i < triangle_sort.size()) {
cluster_indices[solid_cell_index * 2] = cluster_index;
cluster_indices[solid_cell_index * 2 + 1] = i;
uint32_t cell = triangle_sort[i].cell_index;
uint32_t triangle_count = giw[cell * 2];
uint32_t cell_cluster_count = (triangle_count + p_cluster_size - 1) / p_cluster_size;
_sort_triangle_clusters(p_cluster_size, cluster_index, i, triangle_count, triangle_sort, cluster_aabbs);
for (uint32_t j = 0; j < triangle_count; j++) {
tiw[i + j] = triangle_sort[i + j].triangle_index;
}
i += triangle_count;
cluster_index += cell_cluster_count;
solid_cell_index++;
}
}
#if 0
for (int i = 0; i < grid_size; i++) {
@@ -507,7 +602,13 @@ void LightmapperRD::_create_acceleration_structures(RenderingDevice *rd, Size2i
triangle_buffer = rd->storage_buffer_create(tb.size(), tb);
Vector<uint8_t> tib = triangle_indices.to_byte_array();
triangle_cell_indices_buffer = rd->storage_buffer_create(tib.size(), tib);
r_triangle_indices_buffer = rd->storage_buffer_create(tib.size(), tib);
Vector<uint8_t> cib = cluster_indices.to_byte_array();
r_cluster_indices_buffer = rd->storage_buffer_create(cib.size(), cib);
Vector<uint8_t> cab = cluster_aabbs.to_byte_array();
r_cluster_aabbs_buffer = rd->storage_buffer_create(cab.size(), cab);
Vector<uint8_t> lb = lights.to_byte_array();
if (lb.size() == 0) {
@@ -1020,24 +1121,29 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
RID vertex_buffer;
RID triangle_buffer;
RID lights_buffer;
RID triangle_cell_indices_buffer;
RID triangle_indices_buffer;
RID cluster_indices_buffer;
RID cluster_aabbs_buffer;
RID grid_texture;
RID seams_buffer;
RID probe_positions_buffer;
Vector<int> slice_seam_count;
#define FREE_BUFFERS \
rd->free(bake_parameters_buffer); \
rd->free(vertex_buffer); \
rd->free(triangle_buffer); \
rd->free(lights_buffer); \
rd->free(triangle_cell_indices_buffer); \
rd->free(grid_texture); \
rd->free(seams_buffer); \
#define FREE_BUFFERS \
rd->free(bake_parameters_buffer); \
rd->free(vertex_buffer); \
rd->free(triangle_buffer); \
rd->free(lights_buffer); \
rd->free(triangle_indices_buffer); \
rd->free(cluster_indices_buffer); \
rd->free(cluster_aabbs_buffer); \
rd->free(grid_texture); \
rd->free(seams_buffer); \
rd->free(probe_positions_buffer);
_create_acceleration_structures(rd, atlas_size, atlas_slices, bounds, grid_size, probe_positions, p_generate_probes, slice_triangle_count, slice_seam_count, vertex_buffer, triangle_buffer, lights_buffer, triangle_cell_indices_buffer, probe_positions_buffer, grid_texture, seams_buffer, p_step_function, p_bake_userdata);
const uint32_t cluster_size = 16;
_create_acceleration_structures(rd, atlas_size, atlas_slices, bounds, grid_size, cluster_size, probe_positions, p_generate_probes, slice_triangle_count, slice_seam_count, vertex_buffer, triangle_buffer, lights_buffer, triangle_indices_buffer, cluster_indices_buffer, cluster_aabbs_buffer, probe_positions_buffer, grid_texture, seams_buffer, p_step_function, p_bake_userdata);
// Create global bake parameters buffer.
BakeParameters bake_parameters;
@@ -1133,7 +1239,7 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
RD::Uniform u;
u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
u.binding = 3;
u.append_id(triangle_cell_indices_buffer);
u.append_id(triangle_indices_buffer);
base_uniforms.push_back(u);
}
{
@@ -1185,6 +1291,20 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
u.append_id(sampler);
base_uniforms.push_back(u);
}
{
RD::Uniform u;
u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
u.binding = 11;
u.append_id(cluster_indices_buffer);
base_uniforms.push_back(u);
}
{
RD::Uniform u;
u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
u.binding = 12;
u.append_id(cluster_aabbs_buffer);
base_uniforms.push_back(u);
}
}
RID raster_base_uniform = rd->uniform_set_create(base_uniforms, rasterize_shader, 0);
@@ -1230,6 +1350,8 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
Ref<RDShaderFile> compute_shader;
String defines = "";
defines += "\n#define CLUSTER_SIZE " + uitos(cluster_size) + "\n";
if (p_bake_sh) {
defines += "\n#define USE_SH_LIGHTMAPS\n";
}