Outline.hlsl

float3 DecodeViewNormalStereo( float4 enc4 )
{
    float kScale = 1.7777;
    float3 nn = enc4.xyz*float3(2*kScale,2*kScale,0) + float3(-kScale,-kScale,1);
    float g = 2.0 / dot(nn.xyz,nn.xyz);
    float3 n;
    n.xy = g*nn.xy;
    n.z = g-1;
    return n;
}

float3 DecodeNormal( float4 enc)
{
    return DecodeViewNormalStereo (enc);
}

void Outline_float(float4 ScreenPos, float Scale, float DepthThreshold, float NormalThreshold, float2 Texel, Texture2D DepthNormalsTexture, Texture2D DepthTexture, SamplerState Sampler, out float Out)
{
    float halfScaleFloor = floor(Scale * 0.5);
    float halfScaleCeil = ceil(Scale * 0.5);

    float2 bottomLeftUV = ScreenPos.xy - float2(Texel.x, Texel.y) * halfScaleFloor;
    float2 topRightUV = ScreenPos.xy + float2(Texel.x, Texel.y) * halfScaleCeil;
    float2 bottomRightUV = ScreenPos.xy + float2(Texel.x * halfScaleCeil, -Texel.y * halfScaleFloor);
    float2 topLeftUV = ScreenPos.xy + float2(-Texel.x * halfScaleFloor, Texel.y * halfScaleCeil);

    // Depth from DepthTexture
    float depth0 =SAMPLE_TEXTURE2D(DepthTexture, Sampler, bottomLeftUV).r;
    float depth1 =SAMPLE_TEXTURE2D(DepthTexture, Sampler, topRightUV).r;
    float depth2 =SAMPLE_TEXTURE2D(DepthTexture, Sampler, bottomRightUV).r;
    float depth3 =SAMPLE_TEXTURE2D(DepthTexture, Sampler, bottomLeftUV).r;

    float depthFiniteDifference0 = depth1 - depth0;
    float depthFiniteDifference1 = depth3 - depth2;

    float edgeDepth = sqrt(pow(depthFiniteDifference0, 2) + pow(depthFiniteDifference1, 2)) * 100;

    float newDepthThreshold = DepthThreshold * depth0;
    edgeDepth = edgeDepth > newDepthThreshold ? 1 : 0;


    // Normals extracted from DepthNormalsTexture
    float3 normal0 = DecodeNormal(SAMPLE_TEXTURE2D(DepthNormalsTexture, Sampler, bottomLeftUV));
    float3 normal1 = DecodeNormal(SAMPLE_TEXTURE2D(DepthNormalsTexture, Sampler, topRightUV));
    float3 normal2 = DecodeNormal(SAMPLE_TEXTURE2D(DepthNormalsTexture, Sampler, bottomRightUV));
    float3 normal3 = DecodeNormal(SAMPLE_TEXTURE2D(DepthNormalsTexture, Sampler, topLeftUV));

    float3 normalFiniteDifference0 = normal1 - normal0;
    float3 normalFiniteDifference1 = normal3 - normal2;

    float edgeNormal = sqrt(dot(normalFiniteDifference0, normalFiniteDifference0) + dot(normalFiniteDifference1, normalFiniteDifference1));
    edgeNormal = edgeNormal > NormalThreshold ? 1 : 0;


    // Combined
    float edge = max(edgeDepth, edgeNormal);

    Out = edge;
}