merian-nodes: Accumulate: Respect sample count again

LDAP · Sep 20, 2024 · 73cee50 · 73cee50
1 parent f8ea38b
commit 73cee50
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/include/merian-nodes/nodes/accumulate/README.md b/include/merian-nodes/nodes/accumulate/README.md
@@ -21,7 +21,7 @@ Inputs:
 | VkImageIn  | prev_accum   | feedback last `accum`                                                                  | 1     |
 | VkImageIn  | prev_moments | feedback last `moments`                                                                | 1     |
 |            |              |                                                                                        |       |
-| VkImageIn  | irr          | irradiance input (irradiance in `rgb`, sample count in `a`)                            | no    |
+| VkImageIn  | irr          | irradiance input (irradiance in `rgb`, sample count in `a`!)                            | no    |
 |            |              |                                                                                        |       |
 | VkImageIn  | mv           | motion vectors in `r` and `g` channel                                                  | no    |
 | VkImageIn  | moments_in   | moments in `r` and `g` channel                                                         | no    |

diff --git a/src/merian-nodes/nodes/accumulate/accumulate.comp b/src/merian-nodes/nodes/accumulate/accumulate.comp
@@ -131,6 +131,7 @@ void main() {
   if (any(greaterThanEqual(ipos, imageSize(img_accum)))) return;
 
   vec3 irr = texelFetch(img_irr, ipos, 0).rgb;
+  float samples = texelFetch(img_irr, ipos, 0).a;
   vec2 moments = texelFetch(img_moments, ipos, 0).rg;
   vec4 percentiles;
 
@@ -246,8 +247,8 @@ void main() {
       prev_irr_histlen.a = min(1.0 / (1.0 - adaptive_alpha) - 1, prev_irr_histlen.a);
     }
 
-    prev_irr_histlen.a = min(prev_irr_histlen.a + 1, max_history);
-    float alpha = min(pc.accum_alpha, 1. - 1. / prev_irr_histlen.a);
+    float alpha = min(pc.accum_alpha, prev_irr_histlen.a / (prev_irr_histlen.a + samples));
+    prev_irr_histlen.a = min(prev_irr_histlen.a + samples, max_history);
 
     irr     = mix(irr, prev_irr_histlen.rgb, alpha);
     moments = mix(moments,         prev_moments, alpha);