griefith/test
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

EEVEE: Remove shadow ray horizon clipping

Browse Source 
This make the shadow rays always multiply the lighting,
which can make renders with large light sources darker.

This bias introduced too many light leaking issues. And
these issues are made more visible since the introduction
of 410282e156.

Its first use was to avoid self shadowing artifacts from
large light sources. Since the shading was already
integrated over the visible hemisphere, it made sense
that the shadowing was also in the visible hemisphere.

However this only works if the shading is actually
clipped to the visible hemisphere above the geometric
normal, which might not always be the case.

Given it is better to have self shadowing noise than
light leaking, it is better to just removing this trick.
Self shadow noise can be mitigated by increasing the
sample count or by increasing the terminator bias.
Light leaking, on the other hand, has no known workaround.

Fix #136594

Pull Request: https://projects.blender.org/blender/blender/pulls/137485
This commit is contained in:
Clément Foucault
2025-04-15 16:38:52 +02:00
committed by Clément Foucault
parent bbb9b16c88
commit b01cdf7df2
1 changed files with 0 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
source/blender/draw/engines/eevee/shaders/eevee_shadow_tracing_lib.glsl
View File

@@ -134,18 +134,6 @@ void shadow_map_trace_hit_check(inout ShadowMapTracingState state,
/** \} */
/* If the ray direction `L` is below the horizon defined by N (normalized) at the shading point,
* push it just above the horizon so that this ray will never be below it and produce
* over-shadowing (since light evaluation already clips the light shape). */
float3 shadow_ray_above_horizon_ensure(float3 L, float3 N, float max_clip_distance)
{
float distance_to_plane = dot(L, -N);
if (distance_to_plane > 0.0f && distance_to_plane < 0.01f + max_clip_distance) {
L += N * (0.01f + distance_to_plane);
}
return L;
}
/* ---------------------------------------------------------------------- */
/** \name Directional Shadow Map Tracing
* \{ */
@@ -175,8 +163,6 @@ ShadowRayDirectional shadow_ray_generate_directional(
/* Light shape is 1 unit away from the shading point. */
float3 direction = sample_uniform_cone(random_2d, cos(shadow_angle));
direction = shadow_ray_above_horizon_ensure(direction, lNg, max_tracing_distance);
/* It only make sense to trace where there can be occluder. Clamp by distance to near plane. */
direction *= max(texel_radius, dist_to_near_plane / direction.z);
@@ -257,7 +243,6 @@ ShadowRayPunctual shadow_ray_generate_punctual(LightData light,
float3 point_on_light_shape = float3(random_2d, 0.0f);
direction = point_on_light_shape - lP;
direction = shadow_ray_above_horizon_ensure(direction, lNg, shape_radius);
}
else {
float dist;
@@ -274,7 +259,6 @@ ShadowRayPunctual shadow_ray_generate_punctual(LightData light,
float3 point_on_light_shape = right * random_2d.x + up * random_2d.y;
direction = point_on_light_shape - lP;
direction = shadow_ray_above_horizon_ensure(direction, lNg, shape_radius);
}
float3 shadow_position = light_local_data_get(light).shadow_position;
/* Clip the ray to not cross the near plane.