diff --git a/src/pp/pp_vis/pp_vis_core.c b/src/pp/pp_vis/pp_vis_core.c
index 8a5c30e6..e7b6aa3f 100644
--- a/src/pp/pp_vis/pp_vis_core.c
+++ b/src/pp/pp_vis/pp_vis_core.c
@@ -2019,7 +2019,7 @@ void V_TickForever(WaveLaneCtx *lane)
 
 
 
-    if (0)
+    // if (0)
     {
       for (P_Ent *bullet = P_FirstEnt(local_frame); !P_IsEntNil(bullet); bullet = P_NextEnt(bullet))
       {
diff --git a/src/pp/pp_vis/pp_vis_gpu.g b/src/pp/pp_vis/pp_vis_gpu.g
index 8b1e4e2a..c02dfe88 100644
--- a/src/pp/pp_vis/pp_vis_gpu.g
+++ b/src/pp/pp_vis/pp_vis_gpu.g
@@ -75,6 +75,46 @@ ComputeShader(V_ClearParticlesCS, 64)
   }
 }
 
+////////////////////////////////////////////////////////////
+//~ Quads
+
+//////////////////////////////
+//- Vertex shader
+
+VertexShader(V_QuadVS, V_QuadPSInput)
+{
+  V_GpuParams params = G_Dereference<V_GpuParams>(V_ShaderConst_Params)[0];
+  StructuredBuffer<V_Quad> quads = G_Dereference<V_Quad>(params.quads);
+
+  V_Quad quad = quads[SV_InstanceID];
+
+  Vec2 rect_uv = RectUvFromVertexId(SV_VertexID);
+  // Vec2 tex_uv = lerp(quad.tex_uv0, quad.tex_uv1, rect_uv);
+  // Vec2 screen_pos = lerp(quad.p0, quad.p1, rect_uv);
+  Vec2 screen_pos = 0;
+
+  V_QuadPSInput result;
+  result.sv_position = Vec4(NdcFromPos(screen_pos, params.screen_dims).xy, 0, 1);
+  result.quad_idx = SV_InstanceID;
+  return result;
+}
+
+//////////////////////////////
+//- Pixel shader
+
+PixelShader(V_QuadPS, V_QuadPSOutput, V_QuadPSInput input)
+{
+  V_GpuParams params = G_Dereference<V_GpuParams>(V_ShaderConst_Params)[0];
+  StructuredBuffer<V_Quad> quads = G_Dereference<V_Quad>(params.quads);
+  V_Quad quad = quads[input.quad_idx];
+
+  Vec4 final_color = 0;
+
+  V_QuadPSOutput output;
+  output.sv_target0 = final_color;
+  return output;
+}
+
 ////////////////////////////////////////////////////////////
 //~ Backdrop
 
@@ -285,46 +325,6 @@ ComputeShader(V_ClearParticlesCS, 64)
 //   }
 // }
 
-////////////////////////////////////////////////////////////
-//~ Quads
-
-//////////////////////////////
-//- Vertex shader
-
-VertexShader(V_QuadVS, V_QuadPSInput)
-{
-  V_GpuParams params = G_Dereference<V_GpuParams>(V_ShaderConst_Params)[0];
-  StructuredBuffer<V_Quad> quads = G_Dereference<V_Quad>(params.quads);
-
-  V_Quad quad = quads[SV_InstanceID];
-
-  Vec2 rect_uv = RectUvFromVertexId(SV_VertexID);
-  // Vec2 tex_uv = lerp(quad.tex_uv0, quad.tex_uv1, rect_uv);
-  // Vec2 screen_pos = lerp(quad.p0, quad.p1, rect_uv);
-  Vec2 screen_pos = 0;
-
-  V_QuadPSInput result;
-  result.sv_position = Vec4(NdcFromPos(screen_pos, params.screen_dims).xy, 0, 1);
-  result.quad_idx = SV_InstanceID;
-  return result;
-}
-
-//////////////////////////////
-//- Pixel shader
-
-PixelShader(V_QuadPS, V_QuadPSOutput, V_QuadPSInput input)
-{
-  V_GpuParams params = G_Dereference<V_GpuParams>(V_ShaderConst_Params)[0];
-  StructuredBuffer<V_Quad> quads = G_Dereference<V_Quad>(params.quads);
-  V_Quad quad = quads[input.quad_idx];
-
-  Vec4 final_color = 0;
-
-  V_QuadPSOutput output;
-  output.sv_target0 = final_color;
-  return output;
-}
-
 ////////////////////////////////////////////////////////////
 //~ Particle simulation
 
@@ -484,6 +484,8 @@ ComputeShader2D(V_ShadeCS, 8, 8)
   RWTexture2D<Vec4> shade_tex = G_Dereference<Vec4>(params.shade_rw);
   Texture2D<Vec4> albedo_tex = G_Dereference<Vec4>(params.albedo_ro);
   Texture2D<P_TileKind> tiles = G_Dereference<P_TileKind>(params.tiles);
+  RWTexture2D<Vec4> stains = G_Dereference<Vec4>(params.stains);
+  RWTexture2D<f32> drynesses = G_Dereference<f32>(params.drynesses);
   SamplerState wrap_sampler = G_Dereference(params.pt_wrap_sampler);
 
   Vec2 shade_pos = SV_DispatchThreadID + Vec2(0.5, 0.5);
@@ -571,10 +573,22 @@ ComputeShader2D(V_ShadeCS, 8, 8)
       }
     }
 
+    //- Albedo tex color
+    Vec4 albedo_tex_color = albedo_tex.Load(Vec3(shade_pos, 0));
+
+    //- Stain color
+    Vec4 stain_color = 0;
+    {
+      f32 dryness = drynesses.Load(cell_pos);
+      stain_color = V_DryColor(stains.Load(cell_pos), dryness);
+      stain_color.rgb *= 1.0 - (0.75 * tile_is_wall);  // Darken wall stains
+    }
+
     //- Composite albedo
     albedo = BlendPremul(!tile_is_wall * tile_color, albedo);  // Blend floor tile
-    albedo = BlendPremul(albedo_tex.Load(Vec3(shade_pos, 0)), albedo);
+    albedo = BlendPremul(albedo_tex_color, albedo);
     albedo = BlendPremul(tile_is_wall * tile_color, albedo);  // Blend wall tile
+    albedo = BlendPremul(stain_color, albedo);
   }
 
   //////////////////////////////
@@ -710,6 +724,7 @@ PixelShader(V_CompositePS, V_CompositePSOutput, V_CompositePSInput input)
         overlay_color = grid_color;
       }
     }
+
     // Axis
     if (V_ShaderConst_GpuFlags & V_GpuFlag_DebugDraw)
     {
@@ -728,6 +743,7 @@ PixelShader(V_CompositePS, V_CompositePSOutput, V_CompositePSInput input)
         overlay_color = y_axis_color;
       }
     }
+
     // World bounds
     {
       const Vec4 bounds_color = LinearFromSrgb(Vec4(0.75, 0.75, 0, 1));
@@ -741,6 +757,7 @@ PixelShader(V_CompositePS, V_CompositePSOutput, V_CompositePSInput input)
         overlay_color = bounds_color;
       }
     }
+
     // Premultiply
     overlay_color.rgb *= overlay_color.a;
   }