Add wind to grass toping

shaders/voxelCommon.hlsli

@@ -50,7 +50,7 @@ cbuffer VoxelCB : register(b0) {
     uint chunkCount;
     uint bleedMask;       // bit N set = material N can bleed onto neighbors
     uint resistBleedMask; // bit N set = material N resists bleed from neighbors
-    uint _cullPad2;
+    float windTime;  // elapsed time for wind animation (seconds)
 };
 
 // ── Indirect draw args (must match C++ IndirectDrawArgs, 20 bytes) ──

shaders/voxelTopingVS.hlsl

@@ -44,6 +44,24 @@ VSOutput main(uint vertexID : SV_VertexID, uint instanceID : SV_InstanceID) {
 
     float3 worldPos = inst.worldPos + vtx.position;
 
+    // ── Wind animation (vegetation only) ────────────────────────
+    // Height above the voxel face (y=1 in local space) drives amplitude.
+    // Quadratic scaling: base stays anchored, tips sway the most.
+    if (push.materialID != 3u) { // not stone
+        float localHeight = vtx.position.y - 1.0;
+        if (localHeight > 0.0) {
+            float heightFactor = localHeight * localHeight; // quadratic
+            float phase = worldPos.x * 1.8 + worldPos.z * 1.3 + windTime * 3.5;
+            float phase2 = worldPos.x * 0.7 - worldPos.z * 2.1 + windTime * 2.7;
+            float swayX = sin(phase) * 0.11 * heightFactor;
+            float swayZ = cos(phase2) * 0.08 * heightFactor;
+            float swayY = -abs(sin(phase * 0.7)) * 0.02 * heightFactor; // slight droop
+            worldPos.x += swayX;
+            worldPos.y += swayY;
+            worldPos.z += swayZ;
+        }
+    }
+
     VSOutput output;
     output.position  = mul(viewProjection, float4(worldPos, 1.0));
     output.worldPos  = worldPos;

src/voxel/TopingSystem.cpp

@@ -399,7 +399,7 @@ void TopingSystem::generateGrassVariant(TopingDef& def, uint8_t bitmask) {
                 angle += (h1 - 0.5f) * 20.0f;
 
                 // Height: per-blade × per-tuft
-                float bladeHeight = (0.06f + h2 * 0.28f) * tuftHeightScale;
+                float bladeHeight = (0.09f + h2 * 0.42f) * tuftHeightScale; // +50% height
 
                 float baseWidth = 0.030f + h3 * 0.030f;
                 float lean = (0.03f + h4 * 0.12f) * tuftLeanScale;
@@ -457,7 +457,7 @@ void TopingSystem::generateGrassVariant(TopingDef& def, uint8_t bitmask) {
             float angle = (fanT - 0.5f) * 2.0f * 70.0f;
             angle += (h1 - 0.5f) * 15.0f;
 
-            float height    = (0.10f + h2 * 0.22f) * cornerHeightScale;
+            float height    = (0.15f + h2 * 0.33f) * cornerHeightScale; // +50% height
             float baseWidth = 0.030f + h3 * 0.025f;
             float lean      = (0.04f + h4 * 0.10f) * cornerLeanScale;
             float midLean   = 0.10f + h5 * 0.30f;

src/voxel/VoxelRenderer.cpp

@@ -714,7 +714,7 @@ void VoxelRenderer::render(
         // Material IDs: 1=Grass, 2=Dirt, 3=Stone, 4=Sand, 5=Snow
         cb.bleedMask = (1u << 1) | (1u << 2) | (1u << 4) | (1u << 5); // Grass, Dirt, Sand, Snow can bleed (NOT Stone)
         cb.resistBleedMask = (1u << 1); // Grass resists bleed (she bleeds onto others, not the reverse)
-        cb._cullPad2 = 0;
+        cb.windTime = windTime_;
         dev->UpdateBuffer(&constantBuffer_, &cb, cmd, sizeof(cb));
 
         // Render pass
@@ -801,7 +801,7 @@ void VoxelRenderer::render(
     cb.debugBlend = 0.0f;
     cb.bleedMask = 0;
     cb.resistBleedMask = 0;
-    cb._cullPad2 = 0;
+    cb.windTime = windTime_;
     cb.chunkCount = chunkCount_;
     extractFrustumPlanes(vpMatrix, cb.frustumPlanes);
     dev->UpdateBuffer(&constantBuffer_, &cb, cmd, sizeof(cb));
@@ -1466,6 +1466,8 @@ void VoxelRenderPath::Update(float dt) {
     float instantFps = (dt > 0.0f) ? (1.0f / dt) : 0.0f;
     smoothFps_ = smoothFps_ * 0.95f + instantFps * 0.05f;
     if (camera) handleInput(dt);
+    windTime_ += dt;
+    renderer.windTime_ = windTime_;
 
     // Animated terrain: regenerate at 60 Hz with time-shifted noise
     // Fused: regenerate + pack voxel data in the same parallel pass

src/voxel/VoxelRenderer.h

@@ -60,6 +60,7 @@ public:
 
     bool debugFaceColors_ = false;
     bool debugBlend_ = false;
+    float windTime_ = 0.0f;  // set by VoxelRenderPath::Update each frame
 
 private:
     void createPipeline();
@@ -137,7 +138,7 @@ private:
         uint32_t chunkCount;
         uint32_t bleedMask;       // bit N set = material N can bleed onto neighbors
         uint32_t resistBleedMask; // bit N set = material N resists bleed from neighbors
-        uint32_t _cullPad2;
+        float windTime;
     };
     wi::graphics::GPUBuffer constantBuffer_;
 
@@ -236,6 +237,9 @@ private:
     mutable float lastDt_ = 0.016f;
     mutable float smoothFps_ = 60.0f;
 
+    // Wind animation (continuous, always running)
+    float windTime_ = 0.0f;
+
     // Animated terrain (wave effect at 60 Hz, toggled with F3)
     bool animatedTerrain_ = false;
     float animTime_ = 0.0f;