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

shaders/Lib/Programs/Composite/Soild_FS.glsl

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+// MinecraftPT — Soild_FS (Main Lighting Composite)
+// Combines GBuffer data with path-traced diffuse + specular, direct sun,
+// held light, emission, and ambient to produce the final HDR scene.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+#include "/Lib/BasicFunctions/LightingConstants.glsl"
+#include "/Lib/GbufferData.glsl"
+#include "/Lib/BasicFunctions/Blocklight.glsl"
+#include "/Lib/BasicFunctions/HeldLight.glsl"
+#include "/Lib/BasicFunctions/Sunlight_Shadow.glsl"
+#include "/Lib/BasicFunctions/NetherColor.glsl"
+#include "/Lib/PathTracing/Tracer/SampleIRC.glsl"
+
+uniform sampler2D colortex7; // diffuse PT (denoised)
+uniform sampler2D colortex11; // specular PT (denoised)
+uniform sampler2D colortex8; // previous diffuse (for blending)
+uniform sampler2D colortex12; // combined HDR (for historical blend)
+
+layout(location = 0) out vec4 colorOut; // colortex12
+
+void main(){
+	ivec2 texelCoord = ivec2(gl_FragCoord.xy);
+
+	// Skip sky — sky was written by composite20 (Sky_Overworld_FS) into colortex12
+	float depth = texelFetch(depthtex0, texelCoord, 0).r;
+	if (depth >= 1.0){
+		discard;
+	}
+
+	// Read GBuffer
+	GbufferData gbuffer = GetGbufferDataSoild(texelCoord);
+	MaterialMask mask = CalculateMasks(gbuffer.materialID);
+
+	vec3 worldNormal = gbuffer.worldNormal;
+	vec3 vertexNormal = gbuffer.vertexNormal;
+	vec3 albedo = gbuffer.albedo;
+	vec2 lightmap = gbuffer.lightmap;
+
+	// 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;
+
+	// Path-traced diffuse (from half-res colortex6, sampled at full res)
+	vec2 halfCoord = vec2(texelCoord) * 0.5;
+	vec3 diffusePT = textureLod(colortex7, halfCoord / (screenSize * 0.5), 0.0).rgb;
+
+	// Path-traced specular
+	vec3 specularPT = textureLod(colortex11, halfCoord / (screenSize * 0.5), 0.0).rgb;
+
+	// Direct sunlight
+	vec3 sunLight = GetSunlight(viewPos.xyz, worldPos, vertexNormal, worldNormal, lightmap.x);
+
+	// Block light
+	vec3 blockLight = Blocklight(lightmap) * gbuffer.material.emissiveness;
+
+	// Emission from GBuffer
+	vec3 emission = vec3(0.0);
+	emission = texelFetch(colortex0, texelCoord, 0).a * 2.0;
+
+	// Held light
+	float heldShadow = 1.0;
+	vec3 heldLight = GetHeldLight(worldPos, worldNormal, heldShadow);
+
+	// IRC ambient
+	vec3 irc = SampleIRC(worldPos) * 0.3;
+
+	// Combine:
+	// diffuse = albedo * (sun + block + irc + held) + diffusePT
+	// specular = specularPT
+	// emission = emission
+	// HDR output
+
+	vec3 color = vec3(0.0);
+
+	// Diffuse
+	color += albedo * (sunLight + blockLight + irc) * (1.0 - gbuffer.material.metalness);
+	color += albedo * heldLight * heldShadow * gbuffer.material.roughness;
+
+	// Path-traced diffuse contribution (indirect GI)
+	color += diffusePT * albedo * 0.5;
+
+	// Specular
+	color += specularPT * gbuffer.material.reflectionStrength;
+
+	// Emission
+	color += emission;
+
+	// Fresnel-based specular from direct light
+	float NdotV = max(dot(worldNormal, normalize(-viewPos.xyz)), 0.0);
+	float F0 = gbuffer.material.metalness;
+	vec3 fresnel = FresnelSchlick(NdotV, vec3(F0));
+
+	// Direct specular (sun)
+	float NdotL = max(dot(worldNormal, GetSunDirWorld()), 0.0);
+	if (NdotL > 0.0){
+		float roughness = gbuffer.material.roughness;
+		vec3 halfVec = normalize(GetSunDirWorld() + normalize(-viewPos.xyz));
+		float NdotH = max(dot(worldNormal, halfVec), 0.0);
+		float D = GGX_D(NdotH, roughness);
+		float G = Smith_G(NdotV, NdotL, roughness);
+		vec3 specular = fresnel * D * G / (4.0 * NdotV * NdotL + 0.0001);
+		color += GetSunIrradiance() * specular * NdotL * 0.5;
+	}
+
+	// Apply parallax shadow
+	color *= gbuffer.parallaxShadow;
+
+	// Sky mask: if sky, output 0
+	if (mask.sky > 0.5) color = vec3(0.0);
+
+	colorOut = vec4(color, 1.0);
+}