151 lines
3.7 KiB
GLSL
151 lines
3.7 KiB
GLSL
#version 460
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#extension GL_GOOGLE_include_directive : require
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#include "input_structures.glsl"
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layout(location = 0) in vec2 inUV;
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layout(location = 0) out vec4 outColor;
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// Set 0: scene data (see input_structures.glsl)
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// Set 1: SSR inputs
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layout(set = 1, binding = 0) uniform sampler2D hdrColor;
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layout(set = 1, binding = 1) uniform sampler2D posTex;
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layout(set = 1, binding = 2) uniform sampler2D normalTex;
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layout(set = 1, binding = 3) uniform sampler2D albedoTex;
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vec3 getCameraWorldPosition()
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{
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mat4 invView = inverse(sceneData.view);
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return vec3(invView[3]);
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}
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vec3 projectToScreen(vec3 worldPos)
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{
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vec4 clip = sceneData.viewproj * vec4(worldPos, 1.0);
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if (clip.w <= 0.0)
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{
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return vec3(0.0, 0.0, -1.0);
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}
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vec3 ndc = clip.xyz / clip.w;
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if (ndc.x < -1.0 || ndc.x > 1.0 ||
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ndc.y < -1.0 || ndc.y > 1.0 ||
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ndc.z < 0.0 || ndc.z > 1.0)
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{
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return vec3(0.0, 0.0, -1.0);
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}
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vec2 uv = ndc.xy * 0.5 + 0.5;
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return vec3(uv, ndc.z);
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}
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void main()
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{
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vec3 baseColor = texture(hdrColor, inUV).rgb;
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vec4 posSample = texture(posTex, inUV);
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if (posSample.w == 0.0)
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{
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outColor = vec4(baseColor, 1.0);
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return;
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}
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vec3 worldPos = posSample.xyz;
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vec4 normSample = texture(normalTex, inUV);
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vec3 N = normalize(normSample.xyz);
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float roughness = clamp(normSample.w, 0.04, 1.0);
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vec4 albSample = texture(albedoTex, inUV);
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vec3 albedo = albSample.rgb;
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float metallic = clamp(albSample.a, 0.0, 1.0);
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vec3 camPos = getCameraWorldPosition();
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vec3 V = normalize(camPos - worldPos);
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vec3 R = reflect(-V, N);
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float gloss = 1.0 - roughness;
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float reflectivity = gloss * mix(0.04, 1.0, metallic);
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if (reflectivity <= 0.05)
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{
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outColor = vec4(baseColor, 1.0);
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return;
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}
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if (dot(R, V) <= 0.0)
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{
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outColor = vec4(baseColor, 1.0);
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return;
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}
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const int MAX_STEPS = 64;
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const float STEP_LENGTH = 0.5; // world units per step
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const float MAX_DISTANCE = 50.0; // clamp ray length
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const float THICKNESS = 3.0; // world-space thickness tolerance
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int maxSteps = int(mix(8.0, float(MAX_STEPS), reflectivity));
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bool hit = false;
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vec2 hitUV = vec2(0.0);
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float t = STEP_LENGTH;
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for (int i = 0; i < maxSteps; ++i)
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{
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if (t > MAX_DISTANCE) break;
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vec3 samplePos = worldPos + R * t;
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vec3 proj = projectToScreen(samplePos);
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if (proj.z < 0.0)
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{
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break;
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}
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vec2 uv = proj.xy;
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vec4 scenePosSample = texture(posTex, uv);
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if (scenePosSample.w == 0.0)
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{
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t += STEP_LENGTH;
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continue;
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}
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// Compare distances along view direction as a simple intersection test.
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vec3 viewSample = (sceneData.view * vec4(samplePos, 1.0)).xyz;
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vec3 viewScene = (sceneData.view * vec4(scenePosSample.xyz, 1.0)).xyz;
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float depthRay = -viewSample.z;
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float depthScene = -viewScene.z;
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float depthDiff = depthRay - depthScene;
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if (depthRay > 0.0 && depthScene > 0.0 &&
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depthDiff > 0.0 && depthDiff < THICKNESS)
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{
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hit = true;
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hitUV = uv;
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break;
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}
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t += STEP_LENGTH;
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}
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vec3 result = baseColor;
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if (hit)
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{
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vec3 reflColor = texture(hdrColor, hitUV).rgb;
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float NoV = clamp(dot(N, V), 0.0, 1.0);
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float F0 = mix(0.04, 1.0, metallic);
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float F = F0 + (1.0 - F0) * pow(1.0 - NoV, 5.0); // Schlick
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float gloss = 1.0 - roughness;
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float ssrVisibility = gloss;
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float weight = clamp(F * ssrVisibility, 0.0, 1.0);
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result = mix(baseColor, reflColor, weight);
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}
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outColor = vec4(result, 1.0);
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}
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