merian-nodes: Accum: Fix reprojection / better extended search

LDAP · Aug 22, 2024 · 91c7a7a · 91c7a7a
1 parent d21dad3
commit 91c7a7a
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Showing 3 changed files with 22 additions and 22 deletions.
diff --git a/include/merian-shaders/reprojection.glsl b/include/merian-shaders/reprojection.glsl
@@ -17,7 +17,7 @@ float reprojection_weight(const vec3 curr_normal, const vec3 prev_normal, const
                           const float prev_z, const float z_reject_percent) {
 
     return smoothstep(normal_reject_cos, 1.0, dot(curr_normal, prev_normal))                        // Similar normals
-                      * (1.0 - smoothstep(0.0, z_reject_percent * max(curr_z, prev_z), abs(curr_z - prev_z + vel_z) - dot(pixel_offset, grad_z))); // Similar depth
+                      * (1.0 - smoothstep(0.0, z_reject_percent * max(curr_z, prev_z), abs(curr_z + dot(pixel_offset, grad_z) - prev_z + vel_z))); // Similar depth
 }
 
 // Like reprojection_weight but binary
@@ -43,11 +43,13 @@ bool reprojection_intersect_border(inout vec2 prev_pos, const vec2 mv, const vec
     return false;
 }
 
+// pixel = current_pixel + mv
 ivec2 reproject_pixel_nearest(const vec2 pixel) {
     return ivec2(round(pixel));
 }
 
 // Performs stochastic bilinear interpolation when reprojecting
+// pixel = current_pixel + mv
 ivec2 reproject_pixel_stochastic(const vec2 pixel, const float random) {
     const vec2 relative_pos = fract(pixel);
 

diff --git a/src/merian-nodes/nodes/accumulate/accumulate.comp b/src/merian-nodes/nodes/accumulate/accumulate.comp
@@ -105,24 +105,23 @@ void get_prev_extended_search(const vec2 prev_pos,
                               inout vec2 prev_moments,
                               inout float sum_w) {
   const ivec2 prev_ipos = ivec2(round(prev_pos));
+  uint rng_state = pcg3d16(uvec3(pc.iteration, prev_ipos));
 
   [[unroll]]
-  for(int yy = -1; yy <= 1; yy++) {
-    [[unroll]]
-    for(int xx = -1; xx <= 1; xx++) {
-      const ivec2 tc = prev_ipos + ivec2(xx, yy);
-      if(any(greaterThanEqual(tc, textureSize(img_prev_accum, 0))) || any(lessThan(tc, ivec2(0))))
-        continue;
-
-      const GBuffer prev_gbuf = prev_gbuffer[gbuffer_index(tc, imageSize(img_accum))];
-      const vec3 prev_normal = geo_decode_normal(prev_gbuf.enc_normal);
-      const float w = reprojection_weight(normal, prev_normal, pc.normal_reject_cos * 0.8,
-                        linear_z, vel_z, ivec2(xx, yy), grad_z, prev_gbuf.linear_z, pc.z_reject_percent * 2.);
-
-      prev_irr_histlen        += w * texelFetch(img_prev_accum, tc, 0);
-      prev_moments            += w * texelFetch(img_prev_moments, tc, 0).rg;
-      sum_w                   += w;
-    }
+  for(int i = 0; i <= 9; i++) {
+    const ivec2 offset = ivec2(round(XorShift32Vec2(rng_state) * 4)) - 2;
+    const ivec2 tc = prev_ipos + offset;
+    if(any(greaterThanEqual(tc, textureSize(img_prev_accum, 0))) || any(lessThan(tc, ivec2(0))))
+      continue;
+
+    const GBuffer prev_gbuf = prev_gbuffer[gbuffer_index(tc, imageSize(img_accum))];
+    const vec3 prev_normal = geo_decode_normal(prev_gbuf.enc_normal);
+    const float w = reprojection_weight(normal, prev_normal, pc.normal_reject_cos * 0.8,
+                      linear_z, vel_z, offset, grad_z, prev_gbuf.linear_z, pc.z_reject_percent * 2.);
+
+    prev_irr_histlen        += w * texelFetch(img_prev_accum, tc, 0);
+    prev_moments            += w * texelFetch(img_prev_moments, tc, 0).rg;
+    sum_w                   += w;
   }
 }
 

diff --git a/src/merian-nodes/nodes/accumulate/accumulate.cpp b/src/merian-nodes/nodes/accumulate/accumulate.cpp
@@ -186,11 +186,10 @@ Accumulate::NodeStatusFlags Accumulate::properties(Properties& config) {
                           "Reject points with depths farther apart (relative to the max)");
     needs_rebuild |= config.config_options("filter mode", filter_mode,
                                            {"nearest", "bilinear", "stochastic bilinear"});
-    needs_rebuild |=
-        config.config_bool("extended search", extended_search,
-                           "search in a 3x3 radius with weakened rejection thresholds for valid "
-                           "information if nothing was found. Helps "
-                           "with artifacts at edges");
+    needs_rebuild |= config.config_bool(
+        "extended search", extended_search,
+        "search randomly in a 4x4 radius with weakened rejection thresholds for valid "
+        "information if nothing was found.");
     needs_rebuild |=
         config.config_bool("reuse border", reuse_border,
                            "Reuse border information (if valid) for pixel where the motion vector "