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4 commits

Author SHA1 Message Date
aab38bb9b9 Phase 5.1: Naive Surface Nets smooth rendering
Implement CPU-side Naive Surface Nets for smooth voxel surfaces (SmoothStone,
Snow) coexisting with blocky voxels (Grass, Dirt, Stone, Sand).

Key features:
- SmoothMesher with binary SDF, centroid vertex placement, per-axis boundary
  clamping to align with blocky grid at smooth↔blocky transitions
- Cross-chunk connectivity: PAD=2 SDF grid, vertex range [-1, CHUNK_SIZE),
  canonical edge ownership (no duplicate triangles, no z-fighting)
- Face normals oriented by edge axis+sign (robust with binary SDF, unlike
  SDF gradient dot or centroid sampling approaches)
- Y-axis winding fix: sharing cells have different spatial arrangement,
  requiring opposite winding from X and Z axes
- GPU mesher treats smooth neighbors as solid (no blocky faces toward smooth)
- Material blending: primary (smooth-only) + secondary (all counts) per vertex
- Dedicated shaders: voxelSmoothVS (vertex pulling t6) + voxelSmoothPS
  (triplanar + lerp blending between two materials)
- Separate render pass with LoadOp::LOAD after voxels+topings
- New materials: SmoothStone (mat 6), blocky Stone (mat 3) and Dirt patches
  added to world generation for boundary testing
2026-03-27 13:03:55 +01:00
f166394b60 Phase 3: per-material bleed flags + patch-based terrain for blend testing
- Add bleedMask/resistBleedMask bitmasks to CB for per-material blend control
  - Grass: canBleed + resistsBleed (bleeds onto others, nothing bleeds onto it)
  - Stone: no bleed (doesn't overflow, but accepts bleed from others)
  - Other materials: normal bidirectional blending
- PS checks flags before blending: mainResists → skip, !neighCanBleed → skip
- Flatten terrain (heightScale 64→20) for better surface visibility
- Replace altitude-based material bands with noise-based 2D patches
  (3 noise channels create organic patches of all 5 materials on surface)
- Make stone/sand more visually distinct (stone=blue-gray, sand=warm yellow)
- Lower stone heightContrast (1.2→0.5) so neighbors bleed onto it more
2026-03-26 12:47:10 +01:00
d7e69f97ca Phase 3: PS-based texture blending with winner-takes-all heightmap
Replace pre-encoded quad blend data (v1) with per-pixel voxel data
lookups in the pixel shader. The PS reads voxelDataBuffer (SRV t3)
to find neighbor materials dynamically, enabling 2 independent blend
axes, stair-priority neighbor detection, and winner-takes-all
heightmap-driven transitions.

Key design decisions validated through 6 iterations (see
blending_experiments.md):
- Winner-takes-all: material with highest heightmap score wins 100%
  (sharp but organic transitions, not smooth gradient)
- Symmetric bias: bias = 0.5 - weight ensures equal chance at border
- Subtractive corner attenuation (param=0.80): xAdj = xEdge -
  saturate(yEdge - 0.80) reduces blend at corners naturally
- Blend zone = 0.25 voxels from each edge (50% of face)
- Debug mode (F4) visualizes blend zones as colors
2026-03-26 12:14:08 +01:00
5f346bb14a Phase 2: GPU-driven voxel rendering pipeline
Mega-buffer architecture replacing per-chunk GPU buffers:
- Single StructuredBuffer<PackedQuad> for all chunks (2M quads, 16 MB)
- StructuredBuffer<GPUChunkInfo> with per-chunk metadata (position, quad offsets, face groups)
- VS reads chunk info via push constants (b999) for driver-safe chunk indexing
- CPU frustum culling with wi::primitive::Frustum + AABB per chunk
- Quads sorted by face direction in greedy mesher (faceOffsets/faceCounts)
- GPU frustum + backface cull compute shader (voxelCullCS.hlsl)
- GPU binary mesher compute shader baseline (voxelMeshCS.hlsl)
- Indirect draw buffers and timestamp query infrastructure
- README with build instructions and project architecture
2026-03-25 14:24:05 +01:00