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

shaders/Lib/IndividualFunctions/Parallax.glsl

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+// MinecraftPT — Parallax Occlusion Mapping
+// Steep parallax mapping with PCF soft shadows.
+
+#ifndef PARALLAX_GLSL
+#define PARALLAX_GLSL
+
+// Steep parallax mapping
+vec2 ParallaxMapping(vec2 texcoord, vec3 viewDir){
+	float height = texture(tex, texcoord).a;
+	vec2 delta = viewDir.xy / viewDir.z * PARALLAX_DEPTH;
+
+	int numLayers = max(1, int(PARALLAX_QUALITY));
+	float layerDepth = 1.0 / float(numLayers);
+	float currentDepth = 0.0;
+	vec2 currentCoord = texcoord;
+
+	for (int i = 0; i < numLayers; i++){
+		currentCoord -= delta * layerDepth;
+		height = texture(tex, currentCoord).a;
+		currentDepth += layerDepth;
+		if (height < currentDepth) break;
+	}
+
+	// Parallax shadow
+	float shadow = 1.0;
+	#ifdef PARALLAX_SHADOW
+		// PCF shadow
+		for (int i = 0; i < PARALLAX_SHADOW_QUALITY; i++){
+			vec2 shadowCoord = currentCoord + delta * float(i) / float(PARALLAX_SHADOW_QUALITY);
+			shadow *= step(currentDepth - layerDepth * float(i) / float(PARALLAX_SHADOW_QUALITY), texture(tex, shadowCoord).a);
+		}
+		#endif
+
+	return currentCoord;
+}
+
+#endif