wip: uncommitted work gathered before the branch is merged into main

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.render3d/shaders/grass.vert

@@ -84,7 +84,7 @@ vec3 bladeField(vec2 xz, float y) {
   // dry and green patches a few metres across, and the tussocks' own shade of the same green
   float dryp = smoothstep(0.2, 0.8, gnoise(xz * 0.33 + 17.0) * 0.5 + 0.5);
   t *= mix(vec3(0.92, 1.0, 0.95), vec3(1.30, 1.10, 0.62), dryp);
-  return t * (0.72 + 0.56 * (gnoise(xz * 1.9 + 41.0) * 0.5 + 0.5));
+  return t * (0.55 + 0.80 * (gnoise(xz * 1.9 + 41.0) * 0.5 + 0.5));
 }
 
 void main() {

packages/ludic.render3d/shaders/grass_cull.comp

@@ -61,7 +61,7 @@ vec3 bladeField(vec2 xz, float y) {
   t *= mix(vec3(0.7, 0.8, 0.55), vec3(1.1, 1.05, 0.85), patchy);
   float dryp = smoothstep(0.2, 0.8, gnoise(xz * 0.33 + 17.0) * 0.5 + 0.5);
   t *= mix(vec3(0.92, 1.0, 0.95), vec3(1.30, 1.10, 0.62), dryp);
-  return t * (0.72 + 0.56 * (gnoise(xz * 1.9 + 41.0) * 0.5 + 0.5));
+  return t * (0.55 + 0.80 * (gnoise(xz * 1.9 + 41.0) * 0.5 + 0.5));
 }
 
 void main() {
@@ -118,6 +118,13 @@ void main() {
   uint o = (pr.base[b] + slot) * 4u;
   outv[o] = vec4(xz.x, h - 0.02, xz.y, seed);
   outv[o + 1u] = vec4(sin(ang), cos(ang), tall, bw);
-  outv[o + 2u] = vec4(bladeField(xz, h), 0.6 + 0.8 * h4);
+  // each blade its own: a hue a little toward olive or toward blue-green, and in a dry patch more
+  // of them gone to straw - a meadow is mixed blade by blade, not tinted as one
+  vec3 field = bladeField(xz, h);
+  float hj = bladeHash(ci, j, 7) - 0.5;
+  field *= vec3(1.0 + 0.30 * hj, 1.0, 1.0 - 0.30 * hj);
+  float dryp = smoothstep(0.2, 0.8, gnoise(xz * 0.33 + 17.0) * 0.5 + 0.5);
+  if (bladeHash(ci, j, 8) < 0.10 + 0.45 * dryp) field *= vec3(1.45, 1.18, 0.52);
+  outv[o + 2u] = vec4(field, 0.6 + 0.8 * h4);
   outv[o + 3u] = vec4(gn, dist);
 }

packages/ludic.render3d/shaders/model.frag

@@ -142,7 +142,9 @@ void main() {
   // an occlusion term; grass albedo is capped near 0.5 and this was dividing it by five.
   // A blade is a thin thing standing in open air: shaded at the root by its neighbours,
   // not buried.
-  arm = vec3(mix(0.55, 1.0, t), 0.85, 0.0);
+  // the inside of a sward is its own shade: a blade's base sits among its neighbours (the old clumps
+  // got this from the shadow maps, at 4.5 ms; seen from above it is most of a meadow's texture)
+  arm = vec3(mix(0.30, 1.0, smoothstep(0.0, 0.8, t)), 0.85, 0.0);
 #elif defined(CARD)
   // thin grass is lit from either side: face the card toward the sun before shading
   if (dot(N, u_sun_dir) < 0.0) N = -N;

packages/ludic.render3d/shaders/spv/manifest.txt

@@ -2996,10 +2996,11 @@ U 2e2908c8 frag u_half 828 float 1 0
 U 2e2908c8 frag u_texel 832 float 1 0
 U 2e2908c8 frag u_ortho_on 836 float 1 0
 U 2e2908c8 frag u_carpet_on 840 float 1 0
-U 2e2908c8 frag u_snow_line 844 float 1 0
-U 2e2908c8 frag u_lake_level 848 float 1 0
-U 2e2908c8 frag u_wet 852 float 1 0
-U 2e2908c8 frag u_sea_level 856 float 1 0
+U 2e2908c8 frag u_grass_reach 844 float 1 0
+U 2e2908c8 frag u_snow_line 848 float 1 0
+U 2e2908c8 frag u_lake_level 852 float 1 0
+U 2e2908c8 frag u_wet 856 float 1 0
+U 2e2908c8 frag u_sea_level 860 float 1 0
 U 2e2908c8 frag u_lake 864 vec4 1 0
 U 2e2908c8 frag u_origin 880 vec2 1 0
 U 2e2908c8 frag u_view 896 mat4 1 0
@@ -3073,10 +3074,11 @@ U 1f95f31b frag u_half 828 float 1 0
 U 1f95f31b frag u_texel 832 float 1 0
 U 1f95f31b frag u_ortho_on 836 float 1 0
 U 1f95f31b frag u_carpet_on 840 float 1 0
-U 1f95f31b frag u_snow_line 844 float 1 0
-U 1f95f31b frag u_lake_level 848 float 1 0
-U 1f95f31b frag u_wet 852 float 1 0
-U 1f95f31b frag u_sea_level 856 float 1 0
+U 1f95f31b frag u_grass_reach 844 float 1 0
+U 1f95f31b frag u_snow_line 848 float 1 0
+U 1f95f31b frag u_lake_level 852 float 1 0
+U 1f95f31b frag u_wet 856 float 1 0
+U 1f95f31b frag u_sea_level 860 float 1 0
 U 1f95f31b frag u_lake 864 vec4 1 0
 U 1f95f31b frag u_origin 880 vec2 1 0
 U 1f95f31b frag u_view 896 mat4 1 0
@@ -3150,10 +3152,11 @@ U f4382918 frag u_half 828 float 1 0
 U f4382918 frag u_texel 832 float 1 0
 U f4382918 frag u_ortho_on 836 float 1 0
 U f4382918 frag u_carpet_on 840 float 1 0
-U f4382918 frag u_snow_line 844 float 1 0
-U f4382918 frag u_lake_level 848 float 1 0
-U f4382918 frag u_wet 852 float 1 0
-U f4382918 frag u_sea_level 856 float 1 0
+U f4382918 frag u_grass_reach 844 float 1 0
+U f4382918 frag u_snow_line 848 float 1 0
+U f4382918 frag u_lake_level 852 float 1 0
+U f4382918 frag u_wet 856 float 1 0
+U f4382918 frag u_sea_level 860 float 1 0
 U f4382918 frag u_lake 864 vec4 1 0
 U f4382918 frag u_origin 880 vec2 1 0
 U f4382918 frag u_view 896 mat4 1 0
@@ -3227,10 +3230,11 @@ U f2952361 frag u_half 828 float 1 0
 U f2952361 frag u_texel 832 float 1 0
 U f2952361 frag u_ortho_on 836 float 1 0
 U f2952361 frag u_carpet_on 840 float 1 0
-U f2952361 frag u_snow_line 844 float 1 0
-U f2952361 frag u_lake_level 848 float 1 0
-U f2952361 frag u_wet 852 float 1 0
-U f2952361 frag u_sea_level 856 float 1 0
+U f2952361 frag u_grass_reach 844 float 1 0
+U f2952361 frag u_snow_line 848 float 1 0
+U f2952361 frag u_lake_level 852 float 1 0
+U f2952361 frag u_wet 856 float 1 0
+U f2952361 frag u_sea_level 860 float 1 0
 U f2952361 frag u_lake 864 vec4 1 0
 U f2952361 frag u_origin 880 vec2 1 0
 U f2952361 frag u_view 896 mat4 1 0
@@ -3304,10 +3308,11 @@ U a0f2dbac frag u_half 828 float 1 0
 U a0f2dbac frag u_texel 832 float 1 0
 U a0f2dbac frag u_ortho_on 836 float 1 0
 U a0f2dbac frag u_carpet_on 840 float 1 0
-U a0f2dbac frag u_snow_line 844 float 1 0
-U a0f2dbac frag u_lake_level 848 float 1 0
-U a0f2dbac frag u_wet 852 float 1 0
-U a0f2dbac frag u_sea_level 856 float 1 0
+U a0f2dbac frag u_grass_reach 844 float 1 0
+U a0f2dbac frag u_snow_line 848 float 1 0
+U a0f2dbac frag u_lake_level 852 float 1 0
+U a0f2dbac frag u_wet 856 float 1 0
+U a0f2dbac frag u_sea_level 860 float 1 0
 U a0f2dbac frag u_lake 864 vec4 1 0
 U a0f2dbac frag u_origin 880 vec2 1 0
 U a0f2dbac frag u_view 896 mat4 1 0
@@ -3381,10 +3386,11 @@ U 5e4589a1 frag u_half 828 float 1 0
 U 5e4589a1 frag u_texel 832 float 1 0
 U 5e4589a1 frag u_ortho_on 836 float 1 0
 U 5e4589a1 frag u_carpet_on 840 float 1 0
-U 5e4589a1 frag u_snow_line 844 float 1 0
-U 5e4589a1 frag u_lake_level 848 float 1 0
-U 5e4589a1 frag u_wet 852 float 1 0
-U 5e4589a1 frag u_sea_level 856 float 1 0
+U 5e4589a1 frag u_grass_reach 844 float 1 0
+U 5e4589a1 frag u_snow_line 848 float 1 0
+U 5e4589a1 frag u_lake_level 852 float 1 0
+U 5e4589a1 frag u_wet 856 float 1 0
+U 5e4589a1 frag u_sea_level 860 float 1 0
 U 5e4589a1 frag u_lake 864 vec4 1 0
 U 5e4589a1 frag u_origin 880 vec2 1 0
 U 5e4589a1 frag u_view 896 mat4 1 0

packages/ludic.render3d/shaders/terrain.frag

@@ -16,6 +16,7 @@ uniform float u_ortho_on;
 uniform sampler2D u_rock_d;  uniform sampler2D u_rock_n;  uniform sampler2D u_rock_a;
 uniform sampler2D u_snow_d;  uniform sampler2D u_carpet;   // the clump cards baked straight down (alpha = coverage)
 uniform float u_carpet_on;
+uniform float u_grass_reach;   // where the GPU blades stop (0: none): the ground under them is in their shade
 uniform float u_snow_line;
 uniform float u_lake_level;      // the ground just above the water is wet and dark
 // ---- RAIN THAT LEAVES SOMETHING BEHIND -----------------------------------------------------
@@ -339,6 +340,18 @@ vec3 groundShade(vec3 p, vec3 N, float slope, float dist, float viewDepth, bool
       vec3 cc = cp.rgb * vec3(0.5, 0.57, 0.45) * mix(vec3(0.85, 0.92, 0.9), vec3(1.1, 1.05, 0.85), smoothstep(-0.35, 0.35, N.z)) * (0.75 + 0.35 * lush);
       gA = mix(gA, cc, max(cp.a, 0.35) * carpetW * 0.97);
     }
+    // The blades' own patches (grass_cull.comp's bladeField): patchiness and dry patches, so where
+    // the blades thin out the ground they stand on carries the same meadow, not a lawn
+    {
+      float patchy = fbmC(cheap, p.xz * 0.045, 3) * 0.5 + 0.5;
+      float dryp = smoothstep(0.2, 0.8, gnoise(p.xz * 0.33 + 17.0) * 0.5 + 0.5);
+      vec3 pf = mix(vec3(0.7, 0.8, 0.55), vec3(1.1, 1.05, 0.85), patchy) * mix(vec3(0.92, 1.0, 0.95), vec3(1.30, 1.10, 0.62), dryp);
+      // and the tussocks' own shade, half a metre across: where blades stand a pixel wide the ground
+      // is most of what shows, and it has to carry the same light and dark as the blades on it
+      float tus = 0.55 + 0.80 * (gnoise(p.xz * 1.9 + 41.0) * 0.5 + 0.5);
+      gA *= mix(vec3(1.0), pf / vec3(0.95, 0.96, 0.72) * tus, grassW);
+      if (u_grass_reach > 0.0) gA *= mix(1.0, mix(0.50, 1.0, smoothstep(u_grass_reach * 0.25, u_grass_reach, dist)), grassW);
+    }
     // Subalpine forest floor: dark duff where the stands are dense. The photograph-driven
     // term marks duff only where the survey actually shows dense conifer, and is the same
     // at any distance — ground shading must not depend on where the viewer is.