Irradiance Map

Shaders/irradienceconv.fs

@@ -0,0 +1,35 @@
+#version 460 core
+out vec4 FragColor;
+in vec3 localPos;
+
+uniform samplerCube environmentMap;
+
+const float PI = 3.14159265359;
+
+void main(){
+    vec3 normal = normalize(localPos);
+
+    vec3 irradiance = vec3(0.0);
+
+    vec3 up = vec3(0.0, 1.0, 0.0);
+    vec3 right = normalize(cross(up, normal));
+    up = normalize(cross(normal, right));
+
+    float sampleDelta = 0.025;
+    float nrSamples = 0.0;
+
+    for(float phi = 0.0; phi < 2.0 * PI; phi += sampleDelta){
+        for(float theta = 0.0; theta < 0.5 * PI; theta += sampleDelta){
+            // spherical to cartesian
+            vec3 tangentSample = vec3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
+            // tangent space to world
+            vec3 sampleVec = tangentSample.x * right + tangentSample.y * up + tangentSample.z * normal;
+
+
+            irradiance += texture(environmentMap, sampleVec).rgb * cos(theta) * sin(theta);
+            nrSamples++;
+        }
+    }
+    irradiance = PI * irradiance * (1.0 / float(nrSamples));
+    FragColor = vec4(irradiance,1.0);
+}

Shaders/pbr.fs

@@ -12,6 +12,8 @@ uniform sampler2D metallicMap;
 uniform sampler2D normalMap;
 uniform sampler2D roughnessMap;
 uniform sampler2D aoMap;
+uniform samplerCube irradianceMap;
+
 
 uniform vec3 lightPositions[4];
 uniform vec3 lightColors[4];
@@ -21,9 +23,9 @@ const float PI = 3.14159265359;
 
 
 // ratio Refraction vs Reflection (F function)
-vec3 fresnelSchlick (float cosTheta, vec3 F0)
+vec3 fresnelSchlick (float cosTheta, vec3 F0, float roughness)
 {
-    return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
+    return F0 + (max(vec3(1.0- roughness), F0)- F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
 }
 
 // Calculate Normal distribution (D function)
@@ -102,7 +104,7 @@ void main(){
         
         float NDF = DistributionGGX(N,H, roughness);
         float G = GeometrySmith(N,V,L, roughness);
-        vec3 F = fresnelSchlick(max(dot(H,V), 0.0), F0);
+        vec3 F = fresnelSchlick(max(dot(H,V), 0.0), F0, roughness);
 
         vec3 kS = F;
         vec3 kD = vec3(1.0) - kS;
@@ -118,8 +120,15 @@ void main(){
         Lo += (kD * albedo / PI + specular) * radiance * NdotL;
     }
 
+    
+
     // Calculate the ambient term and add it 
-    vec3 ambient = vec3(0.03) * albedo * ao;
+    vec3 kS = fresnelSchlick(max(dot(N,V), 0.0), F0, roughness);
+    vec3 kD = 1.0 - kS;
+    kD *= 1.0 - metallic;
+    vec3 irradiance = texture(irradianceMap, N).rgb;
+    vec3 diffuse = irradiance* albedo;
+    vec3 ambient = (kD * diffuse) * ao;
     vec3 color = ambient + Lo;
 
     // HDR tonemapping

Shaders/skybox2.vs

@@ -0,0 +1,13 @@
+#version 460 core
+layout (location = 0) in vec3 aPos;
+
+out vec3 localPos;
+
+uniform mat4 projection;
+uniform mat4 view;
+
+void main()
+{
+    localPos = aPos;
+    gl_Position = projection * view * vec4(localPos ,1.0);
+}