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Thread: GLSL black ring around object when using PBR lighting

  1. #1

    GLSL black ring around object when using PBR lighting

    Hi, I'm creating a physically based lighting solution in my engine, and I've come across an issue where there's a black ring around the object from the light.

    I'm using this code in the fragment shader:

    Code :
    vec3 fresnelSchlick(float cosTheta, vec3 F0)
    {
    	return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
     
    }
     
    float DistributionGGX(vec3 N, vec3 H, float roughness)
    {
        float a      = roughness*roughness;
        float a2     = a*a;
        float NdotH  = max(dot(N, H), 0.0);
        float NdotH2 = NdotH*NdotH;
     
        float nom   = a2;
        float denom = (NdotH2 * (a2 - 1.0) + 1.0);
        denom = PI * denom * denom;
     
        return nom / denom;
    }
     
    float GeometrySchlickGGX(float NdotV, float roughness)
    {
        float r = (roughness + 1.0);
        float k = (r*r) / 8.0;
     
        float nom   = NdotV;
        float denom = NdotV * (1.0 - k) + k;
     
        return nom / denom;
    }
    float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
    {
        float NdotV = max(dot(N, V), 0.0);
        float NdotL = max(dot(N, L), 0.0);
        float ggx2  = GeometrySchlickGGX(NdotV, roughness);
        float ggx1  = GeometrySchlickGGX(NdotL, roughness);
     
        return ggx1 * ggx2;
    }
     
    float CalculateAttenuation(vec3 lp, float lr, vec3 FragPos) {
        float distance = distance(lp, FragPos);
     
        float saturated = pow(clamp(1 - pow(distance / lr, 4), 0.0, 1.0), 2);
     
        return saturated / (pow(distance, 2) + 1);
    }
    void main()
    {
    	vec3 N = normalize(Normal);
    	vec3 V = normalize(camPos - FragPos);
    	    vec3 F0 = vec3(0.04); 
        F0 = mix(F0, albedo, metallic);
    	vec3 L = normalize(lightPos - FragPos);
    	vec3 H = normalize(V + L);
    	vec3 Lo = vec3(0.0);
    	float distance = length(lightPos - FragPos);
    	//float attenuation = 1 / (distance * distance);
    	//vec3 radiance = vec3(500.0f,500.0f,500.0f) * attenuation;
    	vec3 radiance = (vec3(500.0f,500.0f,500.0f) * CalculateAttenuation(lightPos,100,FragPos) * 5);
     
    	float NDF = DistributionGGX(N,H,roughness);
    	float G = GeometrySmith(N,V,L,roughness);
    	vec3 F = fresnelSchlick(max(dot(H,V), 0.0),F0);
     
    	vec3 kS = F;
         vec3 kD = vec3(1.0) - kS;
         kD *= 1.0 - metallic;	  
     
         vec3 nominator    = NDF * G * F;
         float denominator = 4 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0) + 0.01; 
         vec3 specular     = nominator / denominator;
     
            // add to outgoing radiance Lo
         float NdotL = max(dot(N, L), 0.0);                
         Lo += (kD * albedo / PI + specular) * radiance * NdotL; 
     
    	vec3 ambient = vec3(0.01) * vec3(0.3,0.3,0.3) * ao;
    	vec3 color = ambient + Lo;
    	color = color / (color+vec3(1.0));
    	color=pow(color,vec3(1.0/gamma));
    	outcolor = vec4(color,1.0) * texture(mainTexture,Texcoord);
     
    }

  2. #2
    Member Regular Contributor
    Join Date
    Jul 2012
    Posts
    425
    A screenshot maybe ?

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