seedlingattempt/godot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Optimize lightmapper using triangle clusters on the acceleration structure.

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

157
modules/lightmapper_rd/lm_compute.glsl
View File

@ -119,6 +119,17 @@ const uint RAY_FRONT = 1;
const uint RAY_BACK = 2;
const uint RAY_ANY = 3;
bool ray_box_test(vec3 p_from, vec3 p_inv_dir, vec3 p_box_min, vec3 p_box_max) {
vec3 t0 = (p_box_min - p_from) * p_inv_dir;
vec3 t1 = (p_box_max - p_from) * p_inv_dir;
vec3 tmin = min(t0, t1), tmax = max(t0, t1);
return max(tmin.x, max(tmin.y, tmin.z)) <= min(tmax.x, min(tmax.y, tmax.z));
}
#if CLUSTER_SIZE > 32
#define CLUSTER_TRIANGLE_ITERATION
#endif
uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out vec3 r_normal, out uint r_triangle, out vec3 r_barycentric) {
// World coordinates.
vec3 rel = p_to - p_from;
@ -142,60 +153,106 @@ uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out
uint iters = 0;
while (all(greaterThanEqual(icell, ivec3(0))) && all(lessThan(icell, ivec3(bake_params.grid_size))) && (iters < 1000)) {
uvec2 cell_data = texelFetch(usampler3D(grid, linear_sampler), icell, 0).xy;
if (cell_data.x > 0) { //triangles here
uint triangle_count = cell_data.x;
if (triangle_count > 0) {
uint hit = RAY_MISS;
float best_distance = 1e20;
for (uint i = 0; i < cell_data.x; i++) {
uint tidx = grid_indices.data[cell_data.y + i];
// Ray-Box test.
Triangle triangle = triangles.data[tidx];
vec3 t0 = (triangle.min_bounds - p_from) * inv_dir;
vec3 t1 = (triangle.max_bounds - p_from) * inv_dir;
vec3 tmin = min(t0, t1), tmax = max(t0, t1);
if (max(tmin.x, max(tmin.y, tmin.z)) > min(tmax.x, min(tmax.y, tmax.z))) {
continue; // Ray-Box test failed.
}
// Prepare triangle vertices.
vec3 vtx0 = vertices.data[triangle.indices.x].position;
vec3 vtx1 = vertices.data[triangle.indices.y].position;
vec3 vtx2 = vertices.data[triangle.indices.z].position;
vec3 normal = -normalize(cross((vtx0 - vtx1), (vtx0 - vtx2)));
bool backface = dot(normal, dir) >= 0.0;
float distance;
vec3 barycentric;
if (ray_hits_triangle(p_from, dir, rel_len, vtx0, vtx1, vtx2, distance, barycentric)) {
if (p_any_hit) {
// Return early if any hit was requested.
return RAY_ANY;
}
vec3 position = p_from + dir * distance;
vec3 hit_cell = (position - bake_params.to_cell_offset) * bake_params.to_cell_size;
if (icell != ivec3(hit_cell)) {
// It's possible for the ray to hit a triangle in a position outside the bounds of the cell
// if it's large enough to cover multiple ones. The hit must be ignored if this is the case.
continue;
}
if (!backface) {
// The case of meshes having both a front and back face in the same plane is more common than expected.
// If this is a front-face, bias it closer to the ray origin, so it always wins over the back-face.
distance = max(bake_params.bias, distance - bake_params.bias);
}
if (distance < best_distance) {
hit = backface ? RAY_BACK : RAY_FRONT;
best_distance = distance;
r_distance = distance;
r_normal = normal;
r_triangle = tidx;
r_barycentric = barycentric;
uint cluster_start = cluster_indices.data[cell_data.y * 2];
uint cell_triangle_start = cluster_indices.data[cell_data.y * 2 + 1];
uint cluster_count = (triangle_count + CLUSTER_SIZE - 1) / CLUSTER_SIZE;
uint cluster_base_index = 0;
while (cluster_base_index < cluster_count) {
// To minimize divergence, all Ray-AABB tests on the clusters contained in the cell are performed
// before checking against the triangles. We do this 32 clusters at a time and store the intersected
// clusters on each bit of the 32-bit integer.
uint cluster_test_count = min(32, cluster_count - cluster_base_index);
uint cluster_hits = 0;
for (uint i = 0; i < cluster_test_count; i++) {
uint cluster_index = cluster_start + cluster_base_index + i;
ClusterAABB cluster_aabb = cluster_aabbs.data[cluster_index];
if (ray_box_test(p_from, inv_dir, cluster_aabb.min_bounds, cluster_aabb.max_bounds)) {
cluster_hits |= (1 << i);
}
}
// Check the triangles in any of the clusters that were intersected by toggling off the bits in the
// 32-bit integer counter until no bits are left.
while (cluster_hits > 0) {
uint cluster_index = findLSB(cluster_hits);
cluster_hits &= ~(1 << cluster_index);
cluster_index += cluster_base_index;
// Do the same divergence execution trick with triangles as well.
uint triangle_base_index = 0;
#ifdef CLUSTER_TRIANGLE_ITERATION
while (triangle_base_index < triangle_count)
#endif
{
uint triangle_start_index = cell_triangle_start + cluster_index * CLUSTER_SIZE + triangle_base_index;
uint triangle_test_count = min(CLUSTER_SIZE, triangle_count - triangle_base_index);
uint triangle_hits = 0;
for (uint i = 0; i < triangle_test_count; i++) {
uint triangle_index = triangle_indices.data[triangle_start_index + i];
if (ray_box_test(p_from, inv_dir, triangles.data[triangle_index].min_bounds, triangles.data[triangle_index].max_bounds)) {
triangle_hits |= (1 << i);
}
}
while (triangle_hits > 0) {
uint cluster_triangle_index = findLSB(triangle_hits);
triangle_hits &= ~(1 << cluster_triangle_index);
cluster_triangle_index += triangle_start_index;
uint triangle_index = triangle_indices.data[cluster_triangle_index];
Triangle triangle = triangles.data[triangle_index];
// Gather the triangle vertex positions.
vec3 vtx0 = vertices.data[triangle.indices.x].position;
vec3 vtx1 = vertices.data[triangle.indices.y].position;
vec3 vtx2 = vertices.data[triangle.indices.z].position;
vec3 normal = -normalize(cross((vtx0 - vtx1), (vtx0 - vtx2)));
bool backface = dot(normal, dir) >= 0.0;
float distance;
vec3 barycentric;
if (ray_hits_triangle(p_from, dir, rel_len, vtx0, vtx1, vtx2, distance, barycentric)) {
if (p_any_hit) {
// Return early if any hit was requested.
return RAY_ANY;
}
vec3 position = p_from + dir * distance;
vec3 hit_cell = (position - bake_params.to_cell_offset) * bake_params.to_cell_size;
if (icell != ivec3(hit_cell)) {
// It's possible for the ray to hit a triangle in a position outside the bounds of the cell
// if it's large enough to cover multiple ones. The hit must be ignored if this is the case.
continue;
}
if (!backface) {
// The case of meshes having both a front and back face in the same plane is more common than
// expected, so if this is a front-face, bias it closer to the ray origin, so it always wins
// over the back-face.
distance = max(bake_params.bias, distance - bake_params.bias);
}
if (distance < best_distance) {
hit = backface ? RAY_BACK : RAY_FRONT;
best_distance = distance;
r_distance = distance;
r_normal = normal;
r_triangle = triangle_index;
r_barycentric = barycentric;
}
}
}
#ifdef CLUSTER_TRIANGLE_ITERATION
triangle_base_index += CLUSTER_SIZE;
#endif
}
}
cluster_base_index += 32;
}
if (hit != RAY_MISS) {