Implement image-based lighting in PbrMaterial

[libs/gl.git] / builtin_data / _envmap_irradiance.glsl

diff --git a/builtin_data/_envmap_irradiance.glsl b/builtin_data/_envmap_irradiance.glsl
new file mode 100644 (file)
index 0000000..83b62c8
--- /dev/null
+++ b/builtin_data/_envmap_irradiance.glsl
@@ -0,0 +1,21 @@
+import cubemap_effect;
+import _pbr_prefilter;
+
+#pragma MSP stage(fragment)
+layout(location=0) out vec3 frag_color;
+void main()
+{
+       vec3 normal = normalize(texcoord);
+       vec3 tangent = normalize(abs(normal.x)>abs(normal.y) ? vec3(-normal.z, 0.0, normal.x) : vec3(0.0, -normal.z, normal.y));
+       mat3 orientation = mat3(tangent, cross(normal, tangent), normal);
+
+       vec3 sum = vec3(0.0);
+       for(int i=0; i<n_samples; ++i)
+       {
+               vec2 uv = hammersley(i, n_samples);
+               vec3 dir = orientation*uv_to_hemisphere(uv.x, sqrt(1.0-uv.y));
+               sum += textureLod(environment_map, dir, 0).rgb;
+       }
+
+       frag_color = sum/n_samples;
+}