Initial commit: Minecraft 光追着色器包（从零实现的 path tracing）

2026-09-19 12:06:22 +08:00
commit 59e30822f8
314 changed files with 9259 additions and 0 deletions
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+// MinecraftPT — Exposure_CS
+// Computes the average scene luminance and smooths the exposure over time.
+// Writes the result into a 1x1 R16F image (exposureTex) read by the final pass.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+
+const ivec3 workGroups = ivec3(8, 8, 1);
+layout (local_size_x = 16, local_size_y = 16) in;
+
+layout (r16f) uniform writeonly image2D img_exposureTex;
+
+uniform sampler2D colortex12;
+
+shared float luminanceSum[256];
+
+void main(){
+	ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
+
+	// Downsample luminance from the HDR scene
+	float lum = 0.0;
+	vec2 base = vec2(texel * 4);
+	for (int i = 0; i < 4; i++){
+	for (int j = 0; j < 4; j++){
+		vec3 color = texelFetch(colortex12, ivec2(base + vec2(i, j)), 0).rgb;
+		lum += luminance(color);
+	}}
+	lum /= 16.0;
+
+	// Shared reduction
+	uint local = gl_LocalInvocationID.x + gl_LocalInvocationID.y * 16u;
+	luminanceSum[local] = lum;
+	barrier();
+
+	if (local == 0u){
+		float avg = 0.0;
+		for (uint i = 0u; i < 256u; i++){
+			avg += luminanceSum[i];
+		}
+		avg /= 256.0;
+
+		// Target exposure (inverse of average luminance)
+		float targetExposure = 1.0 / max(avg, 0.001);
+
+		// Read previous exposure for temporal smoothing (single thread)
+		float prevExposure = imageLoad(img_exposureTex, ivec2(0, 0)).r;
+		if (prevExposure <= 0.0) prevExposure = 1.0;
+
+		float adapted = mix(prevExposure, targetExposure, SMOOTH_EXPOSURE);
+		adapted = clamp(adapted, 0.01, 100.0);
+
+		imageStore(img_exposureTex, ivec2(0, 0), vec4(adapted));
+	}
+}