raymarch.hlsl

struct texFunc {
    float2 rotate(float2 uv, float angle) {
        float2x2 rotMat = float2x2(cos(angle), sin(angle), -sin(angle), cos(angle));
        return mul(uv - 0.5, rotMat) + 0.5;
    }
    
    float2 scale(float2 uv, float factor) {
        return (uv - 0.5) * factor + 0.5;
    }
} tf;

float3 normal = normalize(Normal);
float3 tangent = normalize(Tangent);
float3 bitangent = cross(normal, tangent);

float3 rayDir = -ViewDir;
float4 tex = Texture2DSample(Texture, TextureSampler, UV);

float2 uvStep;
uvStep.x = dot(rayDir, tangent) * Gap;
uvStep.y = dot(rayDir, bitangent) * Gap;

for (int i = 1; i <= Step; i++) {
    if (tex.r < Threshold + i * Threshold * 5.0) {
        float f = (Step - (i - 1)) / Step;
        return float3(f,f,f);
    }

    UV += uvStep;
    tex = Texture2DSample(Texture, TextureSampler, UV.xy);
}

return float3(1,1,1) / Step;