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Add transparency support for LightmapGI

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Co-authored-by: Guerro323 <kaltobattle@gmail.com>
This commit is contained in:
Hendrik Brucker
2024-12-16 12:38:23 +01:00
parent 7f5c469292
commit a3525bc015
26 changed files with 442 additions and 95 deletions
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257
modules/lightmapper_rd/lm_compute.glsl
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@ -154,7 +154,8 @@ uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out
vec3 dir_cell = normalize(rel_cell);
vec3 delta = min(abs(1.0 / dir_cell), bake_params.grid_size); // Use bake_params.grid_size as max to prevent infinity values.
ivec3 step = ivec3(sign(rel_cell));
vec3 side = (sign(rel_cell) * (vec3(icell) - from_cell) + (sign(rel_cell) * 0.5) + 0.5) * delta;
const vec3 init_next_cell = vec3(icell) + max(vec3(0), sign(step));
vec3 t_max = mix(vec3(0), (init_next_cell - from_cell) / dir_cell, notEqual(step, vec3(0))); // Distance to next boundary.
uint iters = 0;
while (all(greaterThanEqual(icell, ivec3(0))) && all(lessThan(icell, ivec3(bake_params.grid_size))) && (iters < 1000)) {
@ -225,7 +226,6 @@ uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out
// 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)) {
@ -242,6 +242,17 @@ uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out
}
if (distance < best_distance) {
switch (triangle.cull_mode) {
case CULL_DISABLED:
backface = false;
break;
case CULL_FRONT:
backface = !backface;
break;
case CULL_BACK: // Default behavior.
break;
}
hit = backface ? RAY_BACK : RAY_FRONT;
best_distance = distance;
r_distance = distance;
@ -271,17 +282,16 @@ uint trace_ray(vec3 p_from, vec3 p_to, bool p_any_hit, out float r_distance, out
}
// There should be only one axis updated at a time for DDA to work properly.
bvec3 mask = bvec3(true, false, false);
float m = side.x;
if (side.y < m) {
m = side.y;
mask = bvec3(false, true, false);
if (t_max.x < t_max.y && t_max.x < t_max.z) {
icell.x += step.x;
t_max.x += delta.x;
} else if (t_max.y < t_max.z) {
icell.y += step.y;
t_max.y += delta.y;
} else {
icell.z += step.z;
t_max.z += delta.z;
}
if (side.z < m) {
mask = bvec3(false, false, true);
}
side += vec3(mask) * delta;
icell += ivec3(vec3(mask)) * step;
iters++;
}
@ -294,6 +304,27 @@ uint trace_ray_closest_hit_triangle(vec3 p_from, vec3 p_to, out uint r_triangle,
return trace_ray(p_from, p_to, false, distance, normal, r_triangle, r_barycentric);
}
uint trace_ray_closest_hit_triangle_albedo_alpha(vec3 p_from, vec3 p_to, out vec4 albedo_alpha, out vec3 hit_position) {
float distance;
vec3 normal;
uint tidx;
vec3 barycentric;
uint ret = trace_ray(p_from, p_to, false, distance, normal, tidx, barycentric);
if (ret != RAY_MISS) {
Vertex vert0 = vertices.data[triangles.data[tidx].indices.x];
Vertex vert1 = vertices.data[triangles.data[tidx].indices.y];
Vertex vert2 = vertices.data[triangles.data[tidx].indices.z];
vec3 uvw = vec3(barycentric.x * vert0.uv + barycentric.y * vert1.uv + barycentric.z * vert2.uv, float(triangles.data[tidx].slice));
albedo_alpha = textureLod(sampler2DArray(albedo_tex, linear_sampler), uvw, 0);
hit_position = barycentric.x * vert0.position + barycentric.y * vert1.position + barycentric.z * vert2.position;
}
return ret;
}
uint trace_ray_closest_hit_distance(vec3 p_from, vec3 p_to, out float r_distance, out vec3 r_normal) {
uint triangle;
vec3 barycentric;
@ -392,6 +423,8 @@ vec2 get_vogel_disk(float p_i, float p_rotation, float p_sample_count_sqrt) {
}
void trace_direct_light(vec3 p_position, vec3 p_normal, uint p_light_index, bool p_soft_shadowing, out vec3 r_light, out vec3 r_light_dir, inout uint r_noise, float p_texel_size, out float r_shadow) {
const float EPSILON = 0.00001;
r_light = vec3(0.0f);
r_shadow = 0.0f;
@ -460,6 +493,7 @@ void trace_direct_light(vec3 p_position, vec3 p_normal, uint p_light_index, bool
vec3 light_to_point_bitan = normalize(cross(light_to_point, light_to_point_tan));
uint hits = 0;
float aa_power = 0.0;
for (uint i = 0; i < ray_count; i++) {
// Create a random sample within the texel.
vec2 disk_sample = (halton_map[i] - vec2(0.5)) * p_texel_size * light_data.shadow_blur;
@ -468,9 +502,13 @@ void trace_direct_light(vec3 p_position, vec3 p_normal, uint p_light_index, bool
vec3 origin = p_position - disk_aligned;
vec3 light_dir = normalize(light_pos - origin);
float power = 0.0;
uint power_accm = 0;
vec3 prev_pos = origin;
if (use_soft_shadows) {
uint soft_shadow_hits = 0;
for (uint j = 0; j < shadowing_ray_count; j++) {
origin = prev_pos;
// Optimization:
// Once already traced an important proportion of rays, if all are hits or misses,
// assume we're not in the penumbra so we can infer the rest would have the same result.
@ -490,24 +528,116 @@ void trace_direct_light(vec3 p_position, vec3 p_normal, uint p_light_index, bool
float vogel_index = float(total_ray_count - 1 - (i * shadowing_ray_count + j)); // Start from (total_ray_count - 1) so we check the outer points first.
vec2 light_disk_sample = get_vogel_disk(vogel_index, a, shadowing_ray_count_sqrt) * soft_shadowing_disk_size * light_data.shadow_blur;
vec3 light_disk_to_point = normalize(light_to_point + light_disk_sample.x * light_to_point_tan + light_disk_sample.y * light_to_point_bitan);
float sample_penumbra = 0.0;
bool sample_did_hit = false;
for (uint iter = 0; iter < bake_params.transparency_rays; iter++) {
vec4 hit_albedo = vec4(1.0);
vec3 hit_position;
// Offset the ray origin for AA, offset the light position for soft shadows.
uint ret = trace_ray_closest_hit_triangle_albedo_alpha(origin - light_disk_to_point * (bake_params.bias + length(disk_sample)), p_position - light_disk_to_point * dist, hit_albedo, hit_position);
if (ret == RAY_MISS) {
if (!sample_did_hit) {
sample_penumbra = 1.0;
}
soft_shadow_hits += 1;
break;
} else if (ret == RAY_FRONT || ret == RAY_BACK) {
bool contribute = ret == RAY_FRONT || !sample_did_hit;
if (!sample_did_hit) {
sample_penumbra = 1.0;
sample_did_hit = true;
}
soft_shadow_hits += 1;
if (contribute) {
sample_penumbra = max(sample_penumbra - hit_albedo.a - EPSILON, 0.0);
}
origin = hit_position + r_light_dir * bake_params.bias;
if (sample_penumbra - EPSILON <= 0) {
break;
}
}
}
power += sample_penumbra;
power_accm++;
}
hits += soft_shadow_hits;
} else { // No soft shadows.
float sample_penumbra = 0.0;
bool sample_did_hit = false;
for (uint iter = 0; iter < bake_params.transparency_rays; iter++) {
vec4 hit_albedo = vec4(1.0);
vec3 hit_position;
// Offset the ray origin for AA, offset the light position for soft shadows.
if (trace_ray_any_hit(origin - light_disk_to_point * (bake_params.bias + length(disk_sample)), p_position - light_disk_to_point * dist) == RAY_MISS) {
soft_shadow_hits++;
uint ret = trace_ray_closest_hit_triangle_albedo_alpha(origin + light_dir * (bake_params.bias + length(disk_sample)), light_pos, hit_albedo, hit_position);
if (ret == RAY_MISS) {
if (!sample_did_hit) {
sample_penumbra = 1.0;
}
hits++;
break;
} else if (ret == RAY_FRONT || ret == RAY_BACK) {
bool contribute = ret == RAY_FRONT || !sample_did_hit;
if (!sample_did_hit) {
sample_penumbra = 1.0;
sample_did_hit = true;
}
hits++;
if (contribute) {
sample_penumbra = max(sample_penumbra - hit_albedo.a - EPSILON, 0.0);
}
origin = hit_position + r_light_dir * bake_params.bias;
if (sample_penumbra - EPSILON <= 0) {
break;
}
}
}
hits += soft_shadow_hits;
} else {
// Offset the ray origin based on the disk. Also increase the bias for further samples to avoid bleeding.
if (trace_ray_any_hit(origin + light_dir * (bake_params.bias + length(disk_sample)), light_pos) == RAY_MISS) {
hits++;
power += sample_penumbra;
power_accm = 1;
}
aa_power = power / float(power_accm);
}
penumbra = aa_power;
} else { // No soft shadows.
bool did_hit = false;
penumbra = 0.0;
for (uint iter = 0; iter < bake_params.transparency_rays; iter++) {
vec4 hit_albedo = vec4(1.0);
vec3 hit_position;
uint ret = trace_ray_closest_hit_triangle_albedo_alpha(p_position + r_light_dir * bake_params.bias, light_pos, hit_albedo, hit_position);
if (ret == RAY_MISS) {
if (!did_hit) {
penumbra = 1.0;
}
break;
} else if (ret == RAY_FRONT || ret == RAY_BACK) {
bool contribute = (ret == RAY_FRONT || !did_hit);
if (!did_hit) {
penumbra = 1.0;
did_hit = true;
}
if (contribute) {
penumbra = max(penumbra - hit_albedo.a - EPSILON, 0.0);
}
p_position = hit_position + r_light_dir * bake_params.bias;
if (penumbra - EPSILON <= 0) {
break;
}
}
}
penumbra = float(hits) / float(total_ray_count);
} else {
if (trace_ray_any_hit(p_position + r_light_dir * bake_params.bias, light_pos) == RAY_MISS) {
penumbra = 1.0;
}
penumbra = clamp(penumbra, 0.0, 1.0);
}
r_shadow = penumbra;
@ -533,6 +663,7 @@ vec3 trace_indirect_light(vec3 p_position, vec3 p_ray_dir, inout uint r_noise, f
vec3 position = p_position;
vec3 ray_dir = p_ray_dir;
uint max_depth = max(bake_params.bounces, 1);
uint transparency_rays_left = bake_params.transparency_rays;
vec3 throughput = vec3(1.0);
vec3 light = vec3(0.0);
for (uint depth = 0; depth < max_depth; depth++) {
@ -546,6 +677,8 @@ vec3 trace_indirect_light(vec3 p_position, vec3 p_ray_dir, inout uint r_noise, f
vec3 uvw = vec3(barycentric.x * vert0.uv + barycentric.y * vert1.uv + barycentric.z * vert2.uv, float(triangles.data[tidx].slice));
position = barycentric.x * vert0.position + barycentric.y * vert1.position + barycentric.z * vert2.position;
vec3 prev_normal = ray_dir;
vec3 norm0 = vec3(vert0.normal_xy, vert0.normal_z);
vec3 norm1 = vec3(vert1.normal_xy, vert1.normal_z);
vec3 norm2 = vec3(vert2.normal_xy, vert2.normal_z);
@ -568,13 +701,29 @@ vec3 trace_indirect_light(vec3 p_position, vec3 p_ray_dir, inout uint r_noise, f
direct_light *= bake_params.exposure_normalization;
#endif
vec3 albedo = textureLod(sampler2DArray(albedo_tex, linear_sampler), uvw, 0).rgb;
vec4 albedo_alpha = textureLod(sampler2DArray(albedo_tex, linear_sampler), uvw, 0).rgba;
vec3 emissive = textureLod(sampler2DArray(emission_tex, linear_sampler), uvw, 0).rgb;
emissive *= bake_params.exposure_normalization;
light += throughput * emissive;
throughput *= albedo;
light += throughput * direct_light * bake_params.bounce_indirect_energy;
light += throughput * emissive * albedo_alpha.a;
throughput = mix(throughput, throughput * albedo_alpha.rgb, albedo_alpha.a);
light += throughput * direct_light * bake_params.bounce_indirect_energy * albedo_alpha.a;
if (albedo_alpha.a < 1.0) {
transparency_rays_left -= 1;
depth -= 1;
if (transparency_rays_left <= 0) {
break;
}
// Either bounce off the transparent surface or keep going forward.
float pa = albedo_alpha.a * albedo_alpha.a;
if (randomize(r_noise) > pa) {
normal = prev_normal;
}
position += normal * bake_params.bias;
}
// Use Russian Roulette to determine a probability to terminate the bounce earlier as an optimization.
// <https://computergraphics.stackexchange.com/questions/2316/is-russian-roulette-really-the-answer>
@ -592,9 +741,55 @@ vec3 trace_indirect_light(vec3 p_position, vec3 p_ray_dir, inout uint r_noise, f
// Look for the environment color and stop bouncing.
light += throughput * trace_environment_color(ray_dir);
break;
} else {
// Ignore any other trace results.
break;
} else if (trace_result == RAY_BACK) {
Vertex vert0 = vertices.data[triangles.data[tidx].indices.x];
Vertex vert1 = vertices.data[triangles.data[tidx].indices.y];
Vertex vert2 = vertices.data[triangles.data[tidx].indices.z];
vec3 uvw = vec3(barycentric.x * vert0.uv + barycentric.y * vert1.uv + barycentric.z * vert2.uv, float(triangles.data[tidx].slice));
position = barycentric.x * vert0.position + barycentric.y * vert1.position + barycentric.z * vert2.position;
vec4 albedo_alpha = textureLod(sampler2DArray(albedo_tex, linear_sampler), uvw, 0).rgba;
if (albedo_alpha.a > 1.0) {
break;
}
transparency_rays_left -= 1;
depth -= 1;
if (transparency_rays_left <= 0) {
break;
}
vec3 norm0 = vec3(vert0.normal_xy, vert0.normal_z);
vec3 norm1 = vec3(vert1.normal_xy, vert1.normal_z);
vec3 norm2 = vec3(vert2.normal_xy, vert2.normal_z);
vec3 normal = barycentric.x * norm0 + barycentric.y * norm1 + barycentric.z * norm2;
vec3 direct_light = vec3(0.0f);
#ifdef USE_LIGHT_TEXTURE_FOR_BOUNCES
direct_light += textureLod(sampler2DArray(source_light, linear_sampler), uvw, 0.0).rgb;
#else
// Trace the lights directly. Significantly more expensive but more accurate in scenarios
// where the lightmap texture isn't reliable.
for (uint i = 0; i < bake_params.light_count; i++) {
vec3 light;
vec3 light_dir;
float shadow;
trace_direct_light(position, normal, i, false, light, light_dir, r_noise, p_texel_size, shadow);
direct_light += light * lights.data[i].indirect_energy;
}
direct_light *= bake_params.exposure_normalization;
#endif
vec3 emissive = textureLod(sampler2DArray(emission_tex, linear_sampler), uvw, 0).rgb;
emissive *= bake_params.exposure_normalization;
light += throughput * emissive * albedo_alpha.a;
throughput = mix(mix(throughput, throughput * albedo_alpha.rgb, albedo_alpha.a), vec3(0.0), albedo_alpha.a);
light += throughput * direct_light * bake_params.bounce_indirect_energy * albedo_alpha.a;
position += ray_dir * bake_params.bias;
}
}