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

shaders/Lib/RTWSM/CollapseImportance.glsl

@@ -0,0 +1,33 @@
+// MinecraftPT — RTWSM Collapse Importance
+// Collapses the 2D importance map into a 1D cumulative curve per row.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+
+const ivec3 workGroups = ivec3(RTW_RESOLUTION, 1, 1);
+layout (local_size_x = 1) in;
+
+layout (r32f) uniform writeonly image2D img_rtwImportance2D;
+layout (rg16) uniform writeonly image2D img_rtwWarp1D;
+
+uniform sampler2D rtwImportance2D;
+
+void main(){
+	int y = int(gl_GlobalInvocationID.y);
+
+	// Sum importance across rows -> 1D profile
+	float sum = 0.0;
+	for (int x = 0; x < RTW_RESOLUTION; x++){
+		sum += textureLod(rtwImportance2D, vec2(float(x) / float(RTW_RESOLUTION), float(y) / float(RTW_RESOLUTION_Y)), 0.0).r;
+	}
+
+	// Build cumulative distribution
+	float cumulative = 0.0;
+	for (int x = 0; x < RTW_RESOLUTION; x++){
+		float imp = textureLod(rtwImportance2D, vec2(float(x) / float(RTW_RESOLUTION), float(y) / float(RTW_RESOLUTION_Y)), 0.0).r;
+		cumulative += imp;
+		float normalized = sum > 0.0 ? cumulative / sum : float(x) / float(RTW_RESOLUTION);
+
+		imageStore(img_rtwWarp1D, ivec2(x, y), vec4(normalized, 1.0 - normalized, 0.0, 0.0));
+	}
+}