ichni_Creator_Studio/Assets/Shaders/ScriptablePostProcessor/Shaders/StrobeFlash.shader

Shader "SLS/Postprocessing/StrobeFlash"
{
    SubShader
    {
        Tags
        {
            "RenderType" = "Opaque"
            "RenderPipeline" = "UniversalPipeline"
        }
        ZWrite Off
        Cull Off
        
        HLSLINCLUDE
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
        #include "Packages/com.unity.render-pipelines.core/Runtime/Utilities/Blit.hlsl"
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl"

        // --- 参数定义 ---
        float4 _StrobeColorHigh;
        float4 _StrobeColorLow; 
        float4 _StrobeParams;    
        
        float4 _StrobeAdvParams; 
        // x: Noise Reduction
        // y: Softness
        // z: Outline Thickness
        // w: Outline Threshold (新增：深度差异阈值)

        float4 _LuminanceWeights;

        // --- 辅助函数 ---
        half3 BoxBlur(float2 uv, float radius)
        {
            float4 offset = _BlitTexture_TexelSize.xyxy * radius * float4(-1, -1, 1, 1);
            half3 c1 = SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, uv + offset.xy).rgb;
            half3 c2 = SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, uv + offset.zy).rgb;
            half3 c3 = SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, uv + offset.xw).rgb;
            half3 c4 = SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, uv + offset.zw).rgb;
            return (c1 + c2 + c3 + c4) * 0.25;
        }

        // 修改：增加 threshold 参数
        float GetEdge(float2 uv, float thickness, float threshold)
        {
            if(thickness <= 0) return 0;

            float2 size = _BlitTexture_TexelSize.xy * thickness;
            
            float d1 = SampleSceneDepth(uv + size);
            float d2 = SampleSceneDepth(uv - size);
            float d3 = SampleSceneDepth(uv + float2(size.x, -size.y));
            float d4 = SampleSceneDepth(uv + float2(-size.x, size.y));

            d1 = LinearEyeDepth(d1, _ZBufferParams);
            d2 = LinearEyeDepth(d2, _ZBufferParams);
            d3 = LinearEyeDepth(d3, _ZBufferParams);
            d4 = LinearEyeDepth(d4, _ZBufferParams);

            float diff1 = abs(d1 - d2);
            float diff2 = abs(d3 - d4);
            
            // 使用传入的阈值，而不是写死的 0.1
            // 只有当深度差 > threshold 时，才认为是边缘
            return step(threshold, diff1 + diff2);
        }

        half4 StrobeFlashPassFragment(Varyings input) : SV_Target
        {
            half2 uv = input.texcoord;
            
            float frequency = _StrobeParams.x;
            float threshold = _StrobeParams.y;
            float noiseReduction = _StrobeAdvParams.x;
            float softness = _StrobeAdvParams.y;
            
            // 新增参数获取
            float outlineThickness = _StrobeAdvParams.z;
            float outlineThreshold = max(0.001, _StrobeAdvParams.w); // 防止除0或负数
            
            float3 lumWeights = _LuminanceWeights.rgb;

            // 采样颜色 (带降噪)
            half3 sceneColor;
            if (noiseReduction > 0.01)
            {
                sceneColor = BoxBlur(uv, noiseReduction);
            }
            else
            {
                sceneColor = SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, uv).rgb;
            }

            float luminance = dot(sceneColor, lumWeights);
            float softRange = max(0.001, softness);
            float t = smoothstep(threshold - softRange, threshold + softRange, luminance);

            float isAuto = _StrobeParams.z;
            float isManualInvert = _StrobeParams.w;
            float invertSignal = 0;

            if (isAuto > 0.5)
            {
                invertSignal = step(0, sin(_Time.y * frequency * PI));
            }
            invertSignal = max(invertSignal, isManualInvert);

            // 边缘检测：传入 Thickness 和 Threshold
            float edge = GetEdge(uv, outlineThickness, outlineThreshold);

            t = abs(t - edge);

            float3 finalColor;
            if (invertSignal > 0.5)
            {
                finalColor = lerp(_StrobeColorHigh.rgb, _StrobeColorLow.rgb, t);
            }
            else
            {
                finalColor = lerp(_StrobeColorLow.rgb, _StrobeColorHigh.rgb, t);
            }

            return half4(finalColor, 1);
        }
        ENDHLSL

        Pass
        {
            Name "Strobe Flash Pass"
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment StrobeFlashPassFragment
            ENDHLSL
        }
    }
}