From 8a60170cbad636ffe8a5bf6e6691c67bd751d37f Mon Sep 17 00:00:00 2001
From: Alexander Gauggel <agauggel@uni-koblenz.de>
Date: Thu, 24 Jun 2021 20:30:09 +0200
Subject: [PATCH] [#82] Simple volumetric lighting prototype
---
.../resources/shaders/shader.frag | 32 +++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/projects/voxelization/resources/shaders/shader.frag b/projects/voxelization/resources/shaders/shader.frag
index 13a9fa3d..0569abd1 100644
--- a/projects/voxelization/resources/shaders/shader.frag
+++ b/projects/voxelization/resources/shaders/shader.frag
@@ -68,6 +68,35 @@ vec3 EnvBRDFApprox(vec3 SpecularColor, float Roughness, float NoV )
return SpecularColor * AB.x + AB.y;
}
+float isotropicPhase(){
+ return 1 / pi;
+}
+
+vec3 volumetricLighting(vec3 colorIn, vec3 V, vec3 pos, float d){
+ vec3 color = colorIn;
+
+ int sampleCount = 48;
+ float stepSize = d / sampleCount;
+
+ vec3 scatteringCoefficient = vec3(0.005);
+ vec3 absorptionCoefficient = vec3(0.01);
+ vec3 extinctionCoefficient = scatteringCoefficient + absorptionCoefficient;
+
+ float noiseScale = 0.1;
+ pos += V * noiseScale * interleavedGradientNoise(gl_FragCoord.xy);
+
+ for(int i = 0; i < sampleCount; i++){
+ vec3 samplePoint = pos + V * i * stepSize;
+ float phase = isotropicPhase();
+ vec3 light = lightInfo.sunColor * lightInfo.sunStrength;
+ float shadow = shadowTest(samplePoint, lightInfo, shadowMap, shadowMapSampler, vec2(0));
+ light *= shadow;
+ color += phase * light * scatteringCoefficient * stepSize;
+ color *= exp(-stepSize * extinctionCoefficient);
+ }
+ return color;
+}
+
void main() {
vec3 albedoTexel = texture(sampler2D(albedoTexture, textureSampler), passUV).rgb;
@@ -125,4 +154,7 @@ void main() {
(diffuse + sunSpecular) * sun +
lambertBRDF(albedo) * diffuseTrace +
reflectionBRDF * specularTrace;
+
+ float d = distance(cameraPos, passPos);
+ outColor = volumetricLighting(outColor, V, passPos, d);
}
\ No newline at end of file
--
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