52 lines
1.7 KiB
HLSL
52 lines
1.7 KiB
HLSL
// Copyright (c) Wojciech Figat. All rights reserved.
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#ifndef __TERRAIN_COMMON__
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#define __TERRAIN_COMMON__
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#include "./Flax/Common.hlsl"
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float DecodeHeightmapHeight(float4 value)
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{
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return (float)((int)(value.x * 255.0) + ((int)(value.y * 255) << 8)) / 65535.0;
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}
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float3 DecodeHeightmapNormal(float4 value, out bool isHole)
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{
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isHole = (value.b + value.a) >= 1.9f;
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float2 normalTemp = float2(value.b, value.a) * 2.0f - 1.0f;
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float3 normal = float3(normalTemp.x, sqrt(1.0 - saturate(dot(normalTemp, normalTemp))), normalTemp.y);
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return normalize(normal);
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}
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float SampleHeightmap(Texture2D<float4> heightmap, float2 uv, float mipOffset = 0.0f)
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{
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float4 value = heightmap.SampleLevel(SamplerPointClamp, uv, mipOffset);
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return DecodeHeightmapHeight(value);
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}
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float SampleHeightmap(Texture2D<float4> heightmap, float2 uv, out float3 normal, out bool isHole, float mipOffset = 0.0f)
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{
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float4 value = heightmap.SampleLevel(SamplerPointClamp, uv, mipOffset);
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normal = DecodeHeightmapNormal(value, isHole);
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return DecodeHeightmapHeight(value);
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}
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float3 SampleHeightmap(Texture2D<float4> heightmap, float3 localPosition, float4 localToUV, out float3 normal, out bool isHole, float mipOffset = 0.0f)
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{
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// Sample heightmap
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float2 uv = localPosition.xz * localToUV.xy + localToUV.zw;
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float4 value = heightmap.SampleLevel(SamplerPointClamp, uv, mipOffset);
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// Decode heightmap
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normal = DecodeHeightmapNormal(value, isHole);
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float height = DecodeHeightmapHeight(value);;
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float3 position = float3(localPosition.x, height, localPosition.z);
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// UVs outside the heightmap are empty
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isHole = isHole || any(uv < 0.0f) || any(uv > 1.0f);
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return position;
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}
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#endif
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