136 lines
4.3 KiB
GLSL
136 lines
4.3 KiB
GLSL
Shader "Hidden/TerrainTools/PaintConcavity" {
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Properties{ _MainTex("Texture", any) = "" {} }
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SubShader{
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ZTest Always Cull Off ZWrite Off
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CGINCLUDE
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#include "UnityCG.cginc"
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#include "Packages/com.unity.terrain-tools/Shaders/TerrainTools.hlsl"
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sampler2D _MainTex;
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float4 _MainTex_TexelSize; // 1/width, 1/height, width, height
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sampler2D _BrushTex;
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sampler2D _Heightmap;
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sampler2D _ConcavityRemap;
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float4 _BrushParams;
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#define BRUSH_STRENGTH (_BrushParams[0])
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#define BRUSH_TARGETHEIGHT (_BrushParams[1])
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struct appdata_t {
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float4 vertex : POSITION;
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float2 pcUV : TEXCOORD0;
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};
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struct v2f {
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float4 vertex : SV_POSITION;
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float2 pcUV : TEXCOORD0;
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};
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v2f vert(appdata_t v)
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{
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v2f o;
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o.vertex = UnityObjectToClipPos(v.vertex);
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o.pcUV = v.pcUV;
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return o;
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}
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ENDCG
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Pass
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{
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Name "Paint Concavity"
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CGPROGRAM
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#pragma vertex vert
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#pragma fragment PaintSplatAlphamap
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#define HEIGHT_SAMPLE(__UV__) UnpackHeightmap(tex2D(_Heightmap, __UV__))
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float3 gradient(float2 uv, float epsilon) {
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float upY = max(0.0f, uv.y - epsilon);
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float downY = min(1.0f, uv.y + epsilon);
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float leftX = max(0.0f, uv.x - epsilon);
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float rightX = min(1.0f, uv.x + epsilon);
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//don't need to divide by 8.0f, since we are normalizing
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float dzdx = ((HEIGHT_SAMPLE(float2(rightX, upY)) + 2.0f * HEIGHT_SAMPLE(float2(rightX, uv.y)) + HEIGHT_SAMPLE(float2(rightX, downY))) -
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(HEIGHT_SAMPLE(uint2(leftX, upY)) + 2.0f * HEIGHT_SAMPLE(uint2(leftX, uv.y)) + HEIGHT_SAMPLE(float2(leftX, downY)))) / 8.0f;
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float dzdy = ((HEIGHT_SAMPLE(float2(leftX, downY)) + 2 * HEIGHT_SAMPLE(uint2(uv.x, downY)) + HEIGHT_SAMPLE(uint2(rightX, downY))) -
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(HEIGHT_SAMPLE(float2(leftX, upY)) + 2 * HEIGHT_SAMPLE(float2(uv.x, upY)) + HEIGHT_SAMPLE(float2(rightX, upY)))) / 8.0f;
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float mag = length(float2(dzdx, dzdy));
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return float3(dzdx, dzdy, mag);
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}
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float laplacian(float2 uv, float epsilon) {
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float upY = max(0.0f, uv.y - epsilon);
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float downY = min(1.0f, uv.y + epsilon);
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float leftX = max(0, uv.x - epsilon);
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float rightX = min(1.0f, uv.x + epsilon);
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float3 rightGrad = gradient(float2(rightX, uv.y), epsilon);
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float3 leftGrad = gradient(float2(leftX, uv.y), epsilon);
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float3 downGrad = gradient(float2(uv.x, downY), epsilon);
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float3 upGrad = gradient(float2(uv.x, upY), epsilon);
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//TODO: better quality by using above sampling from the gradient function
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float dgdx = rightGrad.x / rightGrad.z - leftGrad.x / leftGrad.z;
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float dgdy = downGrad.y / downGrad.z - upGrad.y / upGrad.z;
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return (dgdx + dgdy) / 2.0f;
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}
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float4 _ConcavityRange;
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float GetConcavityScale(float2 uv, float h)
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{
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float epsilon = _ConcavityRange.z * _MainTex_TexelSize.x;
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float concavity = saturate(_ConcavityRange.w * laplacian(uv, epsilon));
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//remap according to curve
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return tex2D(_ConcavityRemap, float2(concavity, 0.0f)).r;
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}
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float ApplyBrush(float height, float brushStrength)
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{
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float targetHeight = 1.0f;
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if (targetHeight > height)
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{
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height += brushStrength;
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height = height < targetHeight ? height : targetHeight;
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}
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else
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{
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height -= brushStrength;
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height = height > targetHeight ? height : targetHeight;
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}
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return height;
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}
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float4 PaintSplatAlphamap(v2f i) : SV_Target
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{
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float2 brushUV = PaintContextUVToBrushUV(i.pcUV);
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float2 normalUV = PaintContextUVToBrushUV(i.pcUV);
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// out of bounds multiplier
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float oob = all(saturate(brushUV) == brushUV) ? 1.0f : 0.0f;
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float brushStrength = BRUSH_STRENGTH * oob * UnpackHeightmap(tex2D(_BrushTex, brushUV.xy));
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//float3 normals = normalize(tex2D(_NormalTex, normalUV).rgb * 2.0f - 1.0f);
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float alphaMap = tex2D(_MainTex, i.pcUV).r;
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float h = UnpackHeightmap(tex2D(_Heightmap, i.pcUV));
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float targetAlpha = GetConcavityScale(i.pcUV, h);
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return lerp(alphaMap, targetAlpha, brushStrength);
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}
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ENDCG
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}
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}
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Fallback Off
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} |