I’m having trouble making a shader that has black lines in light and white lines in shadows [see exhibit one]
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Since the game I’m making is also black & white, I guess the code doesn’t necessarily have to know about shadows and light, but rather the colours of the pixels around the edges. Either way I got no clue how to do it - pretty new at shader programming…
Anyhow, here’s the script I got as of now, any help would be greatly appreciated!
Shader "Outlines Post Process Stack"
{
SubShader
{
Cull Off ZWrite Off ZTest Always
Pass
{
HLSLPROGRAM
#pragma vertex Vert
#pragma fragment Frag
#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/StdLib.hlsl"
TEXTURE2D_SAMPLER2D(_MainTex, sampler_MainTex);
TEXTURE2D_SAMPLER2D(_CameraNormalsTexture, sampler_CameraNormalsTexture);
TEXTURE2D_SAMPLER2D(_CameraDepthTexture, sampler_CameraDepthTexture);
float4 _MainTex_TexelSize;
float _Scale;
float4 _Color;
float _DepthThreshold;
float _DepthNormalThreshold;
float _DepthNormalThresholdScale;
float _NormalThreshold;
float4x4 _ClipToView;
float4 alphaBlend(float4 top, float4 bottom)
{
float3 color = (top.rgb * top.a) + (bottom.rgb * (1 - top.a));
float alpha = top.a + bottom.a * (1 - top.a);
return float4(color, alpha);
}
struct Varyings
{
float4 vertex : SV_POSITION;
float2 texcoord : TEXCOORD0;
float2 texcoordStereo : TEXCOORD1;
float3 viewSpaceDir : TEXCOORD2;
#if STEREO_INSTANCING_ENABLED
uint stereoTargetEyeIndex : SV_RenderTargetArrayIndex;
#endif
};
Varyings Vert(AttributesDefault v)
{
Varyings o;
o.vertex = float4(v.vertex.xy, 0.0, 1.0);
o.texcoord = TransformTriangleVertexToUV(v.vertex.xy);
o.viewSpaceDir = mul(_ClipToView, o.vertex).xyz;
#if UNITY_UV_STARTS_AT_TOP
o.texcoord = o.texcoord * float2(1.0, -1.0) + float2(0.0, 1.0);
#endif
o.texcoordStereo = TransformStereoScreenSpaceTex(o.texcoord, 1.0);
return o;
}
float4 Frag(Varyings i) : SV_Target
{
float halfScaleFloor = floor(_Scale * 0.5);
float halfScaleCeil = ceil(_Scale * 0.5);
float2 bottomLeftUV = i.texcoord - float2(_MainTex_TexelSize.x, _MainTex_TexelSize.y) * halfScaleFloor;
float2 topRightUV = i.texcoord + float2(_MainTex_TexelSize.x, _MainTex_TexelSize.y) * halfScaleCeil;
float2 bottomRightUV = i.texcoord + float2(_MainTex_TexelSize.x * halfScaleCeil, -_MainTex_TexelSize.y * halfScaleFloor);
float2 topLeftUV = i.texcoord + float2(-_MainTex_TexelSize.x * halfScaleFloor, _MainTex_TexelSize.y * halfScaleCeil);
float3 normal0 = SAMPLE_TEXTURE2D(_CameraNormalsTexture, sampler_CameraNormalsTexture, bottomLeftUV).rgb;
float3 normal1 = SAMPLE_TEXTURE2D(_CameraNormalsTexture, sampler_CameraNormalsTexture, topRightUV).rgb;
float3 normal2 = SAMPLE_TEXTURE2D(_CameraNormalsTexture, sampler_CameraNormalsTexture, bottomRightUV).rgb;
float3 normal3 = SAMPLE_TEXTURE2D(_CameraNormalsTexture, sampler_CameraNormalsTexture, topLeftUV).rgb;
float depth0 = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, bottomLeftUV).r;
float depth1 = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, topRightUV).r;
float depth2 = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, bottomRightUV).r;
float depth3 = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, topLeftUV).r;
float3 viewNormal = normal0 * 2 - 1;
float NdotV = 1 - dot(viewNormal, -i.viewSpaceDir);
float normalThreshold01 = saturate((NdotV - _DepthNormalThreshold) / (1 - _DepthNormalThreshold));
float normalThreshold = normalThreshold01 * _DepthNormalThresholdScale + 1;
float depthThreshold = _DepthThreshold * depth0 * normalThreshold;
float depthFiniteDifference0 = depth1 - depth0;
float depthFiniteDifference1 = depth3 - depth2;
float edgeDepth = sqrt(pow(depthFiniteDifference0, 2) + pow(depthFiniteDifference1, 2)) * 100;
edgeDepth = edgeDepth > depthThreshold ? 1 : 0;
float3 normalFiniteDifference0 = normal1 - normal0;
float3 normalFiniteDifference1 = normal3 - normal2;
float edgeNormal = sqrt(dot(normalFiniteDifference0, normalFiniteDifference0) + dot(normalFiniteDifference1, normalFiniteDifference1));
edgeNormal = edgeNormal > _NormalThreshold ? 1 : 0;
float edge = max(edgeDepth, edgeNormal);
float4 edgeColor = float4(_Color.rgb, _Color.a * edge);
float4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
return alphaBlend(edgeColor, color);
}
ENDHLSL
}
}
}