bvle-voxels/shaders/voxelTopingPS.hlsl

// BVLE Voxels - Toping Pixel Shader (Phase 4.2)
// Simplified version of voxelPS: triplanar texture sampling + basic lighting.
// No height-based blending (topings are small decorative meshes).

#include "voxelCommon.hlsli"

Texture2DArray<float4> materialTextures : register(t1);
SamplerState texSampler : register(s0);

struct PSInput {
    float4 position : SV_POSITION;
    float3 worldPos : WORLDPOS;
    float3 normal   : NORMAL;
    nointerpolation uint materialID : MATERIALID;
};

[RootSignature(VOXEL_ROOTSIG)]
float4 main(PSInput input) : SV_TARGET0 {
    float3 N = normalize(input.normal);
    float tiling = textureTiling;

    // Material texture index (materialID 1-5 → array layer 0-4)
    uint texIdx = clamp(input.materialID - 1u, 0u, 4u);

    // Triplanar sampling (same as voxel PS)
    float3 blend = abs(N);
    blend = blend / (blend.x + blend.y + blend.z + 0.001);

    float4 xSample = materialTextures.Sample(texSampler, float3(input.worldPos.yz * tiling, (float)texIdx));
    float4 ySample = materialTextures.Sample(texSampler, float3(input.worldPos.xz * tiling, (float)texIdx));
    float4 zSample = materialTextures.Sample(texSampler, float3(input.worldPos.xy * tiling, (float)texIdx));

    float3 texColor = (xSample.rgb * blend.x + ySample.rgb * blend.y + zSample.rgb * blend.z);

    // Basic directional lighting + ambient
    float3 L = normalize(-sunDirection.xyz);
    float NdotL = max(dot(N, L), 0.0);
    float3 ambient = float3(0.15, 0.18, 0.25);
    float3 lit = texColor * (sunColor.rgb * NdotL + ambient);

    return float4(lit, 1.0);
}