Reduce weathering decal strength and mip-filter clamped decals

crates/skate-game/src/retail_depth.wgsl

@@ -5,7 +5,7 @@
 #ifdef MOTION_VECTOR_PREPASS
 #import bevy_pbr::pbr_prepass_functions::calculate_motion_vector
 #endif
-struct WorldParams { mode: vec4<f32>, foliage_debug: vec4<f32>, surface: vec4<f32>, family: vec4<f32>, fog_ramp: vec4<f32>, fog_color: vec4<f32>, shadow_color: vec4<f32>, sun_direction: vec4<f32>, water: array<vec4<f32>, 4> }
+struct WorldParams { mode: vec4<f32>, foliage_debug: vec4<f32>, surface: vec4<f32>, family: vec4<f32>, fog_ramp: vec4<f32>, fog_color: vec4<f32>, shadow_color: vec4<f32>, sun_direction: vec4<f32>, decal: vec4<f32>, water: array<vec4<f32>, 4> }
 @group(#{MATERIAL_BIND_GROUP}) @binding(0) var<uniform> p: WorldParams;
 @group(#{MATERIAL_BIND_GROUP}) @binding(1) var diffuse: texture_2d<f32>;
 @group(#{MATERIAL_BIND_GROUP}) @binding(2) var diffuse_sampler: sampler;

crates/skate-game/src/retail_render.rs

@@ -47,7 +47,7 @@ fn compare_weathering(
         1 => "Repeating grime OFF; decals ON",
         2 => "Repeating grime ON; decals OFF",
         3 => "Repeating grime OFF; decals OFF",
-        _ => "Authored grime and decals ON",
+        _ => "Normal grime and decals ON",
     };
     for (_, material) in materials.iter_mut() {
         let family = material.params.mode.x as u32;
@@ -98,6 +98,8 @@ pub(crate) struct WorldParams {
     pub fog_color: Vec4,
     pub shadow_color: Vec4,
     pub sun_direction: Vec4,
+    // Wear-only visual tuning; artwork retains unit opacity.
+    pub decal: Vec4,
     pub water: [Vec4; 4],
 }
 
@@ -270,7 +272,7 @@ impl Definition {
             texture(
                 b.map_or(fallback, |b| b.texture),
                 if clamp || b.is_some_and(|b| b.u == 1 && b.v == 1) {
-                    4
+                    if role == "decal" { 6 } else { 4 }
                 } else {
                     3
                 },
@@ -339,6 +341,7 @@ impl Definition {
                 fog_color: Vec4::ZERO,
                 shadow_color: Vec4::ZERO,
                 sun_direction: Vec3::new(4., 7., 4.).normalize().extend(0.),
+                decal: Vec4::new(stain_opacity(self.parameters.get("decal").and_then(|v| v.first()).map(String::as_str).unwrap_or("")), 0., 0., 0.),
                 water,
             },
             diffuse,
@@ -356,6 +359,29 @@ impl Definition {
     }
 }
 
+// The source labels distinguish weathering from graphics. This is an explicit
+// visual tuning choice, not a recovered native material constant. Keep arrows,
+// logos, paint, scratches and edge wear at their authored alpha.
+fn stain_opacity(texture_label: &str) -> f32 {
+    let label = texture_label.to_ascii_lowercase();
+    if ["grime", "grunge", "stain", "oildirt", "drainage", "ground_decals"]
+        .iter().any(|word| label.contains(word)) { 0.35 } else { 1. }
+}
+
+#[cfg(test)]
+mod stain_tests {
+    use super::stain_opacity;
+    #[test]
+    fn weathering_tuning_preserves_artwork() {
+        for name in ["decal_WEAR_WaterStain_01", "subway_grunge03", "decal_GrimePuddle", "OT_Ground_decals"] {
+            assert_eq!(stain_opacity(name), 0.35);
+        }
+        for name in ["decal_Graphic_SP_UN_Shark_01", "decal_other_sp_arrowramps_01", "decal_Graphic_SP_UN_MegaRmp_01", "decal_Wear_GL_UN_MPedge_01", "decal_skateboardscratcheswood01", ""] {
+            assert_eq!(stain_opacity(name), 1.);
+        }
+    }
+}
+
 /// Native renderer box-filters decoded UNORM cube faces down to 1x1.
 /// The same chain prevents aliasing of repeating world maps at distance.
 pub(crate) fn mip_chain(rgba: &[u8], width: u32, height: u32, layers: u32) -> (Vec<u8>, u32) {

crates/skate-game/src/retail_world.wgsl

@@ -3,7 +3,7 @@
 
 struct WorldParams {
     mode: vec4<f32>, foliage_debug: vec4<f32>, surface: vec4<f32>, family: vec4<f32>,
-    fog_ramp: vec4<f32>, fog_color: vec4<f32>, shadow_color: vec4<f32>, sun_direction: vec4<f32>, water: array<vec4<f32>, 4>,
+    fog_ramp: vec4<f32>, fog_color: vec4<f32>, shadow_color: vec4<f32>, sun_direction: vec4<f32>, decal: vec4<f32>, water: array<vec4<f32>, 4>,
 }
 @group(#{MATERIAL_BIND_GROUP}) @binding(0) var<uniform> p: WorldParams;
 @group(#{MATERIAL_BIND_GROUP}) @binding(1) var diffuse: texture_2d<f32>;
@@ -174,7 +174,7 @@ fn fragment(i: VertexOutput) -> @location(0) vec4<f32> {
         lin = d;
         if fam == 11u { lin *= p.family.w; }
     } else {
-        if (fam == 3u || fam == 4u) && (flags & 8u) != 0u && (flags & 512u) == 0u { d = mix(d,art.rgb*art.rgb,art.a); }
+        if (fam == 3u || fam == 4u) && (flags & 8u) != 0u && (flags & 512u) == 0u { d = mix(d,art.rgb*art.rgb,art.a*p.decal.x); }
         if (flags & 4u) != 0u && fam < 13u && (flags & 256u) == 0u { d *= saturate((overlay_sample-0.5)*p.surface.y+0.5); }
         var kd = 0.93429;
         if (fam <= 6u || fam == 13u) && (flags & 1u) != 0u {

crates/skate-game/src/skate_world.rs

@@ -481,7 +481,7 @@ pub(crate) fn spawn(
                         format,
                         RenderAssetUsages::RENDER_WORLD,
                     );
-                    if role == 3 || cube {
+                    if role == 3 || role == 6 || cube {
                         let (bytes, levels) = crate::retail_render::mip_chain(&source.rgba, source.width, height, layers);
                         image.data = Some(bytes);
                         image.texture_descriptor.mip_level_count = levels;
@@ -492,7 +492,7 @@ pub(crate) fn spawn(
                         });
                     }
                     let mut sampler = bevy::image::ImageSamplerDescriptor::linear();
-                    if role != 1 && role != 4 && !cube {
+                    if role != 1 && role != 4 && role != 6 && !cube {
                         sampler.address_mode_u = bevy::image::ImageAddressMode::Repeat;
                         sampler.address_mode_v = bevy::image::ImageAddressMode::Repeat;
                     }

docs/dynamic-props-and-grime.md

@@ -1,5 +1,25 @@
 # Authored props and grime follow-up
 
+## Targeted decal correction after layer test
+
+The user rechecked the comparison and identified decals as the unwanted layer.
+Repeating grime is unchanged. Wear/stain decals now use 35% of their texture's
+alpha; source UVs, dimensions, texture RGB and placement are retained. This is
+explicit visual tuning based on the user's feedback, not proof of the original
+game's intended opacity and not a recovered native shader constant.
+
+Classification uses the material's authored `decal` texture label for grime,
+grunge, stain, oil-dirt, drainage and ground-decal entries. Arrows, logos,
+scratches and ramp edge paint retain full authored opacity. A regression test
+covers this separation. This is not a blanket fade on every decal material.
+
+Clamped decals also now receive a mip chain, independently of lightmaps, which
+remain bilinear mip zero. Previously the shared clamp texture role omitted mips
+for both, leaving fine decal alpha detail unfiltered at distance. The new decal
+role retains clamp addressing while permitting mip filtering. No map re-export
+or owned texture modification is needed. GPU visual verification remains for
+the user; source and shader checks cannot confirm the preferred visual strength.
+
 ## Grime investigation after user retest
 
 The UV-scale correction did not resolve the user's reported visual mismatch.