EEVEE: Ambient Occlusion: Refactor

- Fix noise/banding artifact on distant geometry.
- Fix overshadowing on un-occluded surfaces at grazing angle producing "fresnel"
  like shadowing. Some of it still appears but this is caused to the low number
  of horizons per pixel.
- Improve performance by using a fixed number of samples and fixing the
  sampling area size. A better sampling pattern is planned to recover
  the lost precision on large AO radius.
- Improved normal reconstruction for the AO pass.
- Improve Bent Normal reconstruction resulting in less faceted look on
  smoothed geometry.
- Add Thickness heuristic to avoid overshadowing of thin objects.
  Factor is currently hardcoded.
- Add bent normal support to Glossy reflections.
- Change Glossy occlusion to give less light leaks from lightprobes.
  It can overshadow on smooth surface but this should be mitigated by
  using SSR.
- Use Bent Normal for rough Glossy surfaces.
- Occlusion is now correctly evaluated for each BSDF. However this does make
  everything slower. This is mitigated by the fact the search is a lot faster
  than before.

1 files changed, 2 insertions, 6 deletions

diff --git a/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl b/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
index cb4d8931af0..241b9240606 100644
--- a/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
+++ b/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
@@ -1,13 +1,9 @@
 
 #pragma BLENDER_REQUIRE(common_math_lib.glsl)
 
-vec3 diffuse_dominant_dir(vec3 N, vec3 vis_cone_dir, float vis_cone_aperture_cos)
+vec3 diffuse_dominant_dir(vec3 bent_normal)
 {
-  /* TODO(fclem) revisit this. bent too much towards vis_cone_dir. */
-  vis_cone_aperture_cos *= sqr(vis_cone_aperture_cos);
-
-  N = mix(vis_cone_dir, N, vis_cone_aperture_cos);
-  return normalize(N);
+  return bent_normal;
 }
 
 vec3 specular_dominant_dir(vec3 N, vec3 V, float roughness)