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fix: terrain variation height blend fix #1320

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Merged
alandtse merged 1 commit into from
Jul 28, 2025
Merged

fix: terrain variation height blend fix #1320

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39 changes: 15 additions & 24 deletions features/Terrain Variation/Shaders/TerrainVariation/TerrainVariation.hlsli
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Original file line number Diff line number Diff line change
Expand Up @@ -148,35 +148,26 @@ inline float4 StochasticEffect(Texture2D tex, SamplerState samp, float2 uv, Stoc
float4 sample2 = tex.SampleLevel(samp, uv + offsets.offset2, mipLevel);
float4 sample3 = tex.SampleLevel(samp, uv + offsets.offset3, mipLevel);

// Simplified blending for better performance - reduce contrast calculation overhead
float3 blendWeights = saturate(offsets.weights);
// Full height-based blending for terrain
float contrastFactor = HEIGHT_BLEND_CONTRAST * (1.0 - HEIGHT_INFLUENCE);
float3 blendWeights = pow(saturate(offsets.weights), contrastFactor);

// Gradual fade-out of height blending based on distance (mip level)
float heightBlendFactor = saturate(1.0 - (mipLevel - 1.0) / 2.0); // Fade from mip 1.0 to 3.0
// Height calculation - use luminance for RGB data, alpha when available
float3 luminanceHeights = float3(
dot(sample1.rgb, LUMINANCE_WEIGHTS),
dot(sample2.rgb, LUMINANCE_WEIGHTS),
dot(sample3.rgb, LUMINANCE_WEIGHTS)
);

if (heightBlendFactor > 0.0)
{
// Use Extended Materials style height blending for better quality
float3 heights = float3(sample1.a, sample2.a, sample3.a);

// Apply distance-based fade to height influence
float heightBlend = 1.0 + (HEIGHT_INFLUENCE * heightBlendFactor * 2.0); // Scale similar to ExtendedMaterials HEIGHT_POWER
float3 alphaValues = float3(sample1.a, sample2.a, sample3.a);
float3 alphaMask = step(0.001, alphaValues);
float3 heights = lerp(luminanceHeights, alphaValues, alphaMask);

// Apply height-based weighting (simplified version of ExtendedMaterials ProcessTerrainHeightWeights)
float3 heightWeights = blendWeights * pow(heightBlend, 8.0 * heights); // HEIGHT_MULT = 8
heightWeights = min(100.0, pow(heightWeights, heightBlend));

// Normalize weights
blendWeights = NormalizeWeights(heightWeights);
}
else
{
// Skip expensive height calculations for distant terrain
blendWeights = NormalizeWeights(blendWeights);
}
// Combined weight calculation and normalization
float3 weights = NormalizeWeights(blendWeights * (1.0 + HEIGHT_INFLUENCE * heights));

// Final blend
return sample1 * blendWeights.x + sample2 * blendWeights.y + sample3 * blendWeights.z;
return sample1 * weights.x + sample2 * weights.y + sample3 * weights.z;
}

// Stochastic sampling function without height blending for better performance
Expand Down