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

shaders/Lib/Programs/Composite/WaterRefraction_FS.glsl

@@ -0,0 +1,53 @@
+// MinecraftPT — WaterRefraction_FS
+// Water refraction pass: sample the solid scene with wave-based offset.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+#include "/Lib/GbufferData.glsl"
+#include "/Lib/IndividualFunctions/WaterWaves.glsl"
+
+uniform sampler2D colortex12; // solid scene
+uniform sampler2D colortex4;  // translucent albedo
+
+layout(location = 0) out vec4 colorOut;
+
+void main(){
+	ivec2 texelCoord = ivec2(gl_FragCoord.xy);
+
+	float depth = texelFetch(depthtex0, texelCoord, 0).r;
+	if (depth >= 1.0){
+		colorOut = texelFetch(colortex12, texelCoord, 0);
+		return;
+	}
+
+	vec4 gbuffer5 = texelFetch(colortex5, texelCoord, 0);
+	float matID = gbuffer5.a * 255.0;
+
+	if (matID != MATID_WATER){
+		colorOut = texelFetch(colortex12, texelCoord, 0);
+		return;
+	}
+
+	// Reconstruct world position
+	vec4 viewPos = gbufferProjectionInverse * vec4(vec2(texelCoord) / screenSize * 2.0 - 1.0, depth * 2.0 - 1.0, 1.0);
+	viewPos.xyz /= viewPos.w;
+	vec3 worldPos = gbufferModelViewInverse[3].xyz + viewPos.xyz;
+
+	// Wave normal-based refraction offset
+	vec3 waveNormal = GetWaveNormal(worldPos, 0.5);
+	vec3 viewDir = normalize(-viewPos.xyz);
+	vec3 refracted = refract(viewDir, waveNormal, 0.75);
+
+	// Sample the solid scene with the refraction offset
+	vec3 refractedDir = mat3(gbufferModelView) * refracted;
+	vec2 refractedCoord = viewPos.xy / viewPos.z * refractedDir.xy / refractedDir.z * 0.5 + 0.5;
+	vec2 sampleCoord = refractedCoord * screenSize;
+
+	vec3 color = textureLod(colortex12, sampleCoord / screenSize, 0.0).rgb;
+
+	// Water depth color fade
+	vec3 waterColor = texelFetch(colortex4, texelCoord, 0).rgb;
+	color = mix(color, waterColor, 0.3);
+
+	colorOut = vec4(color, 1.0);
+}