 #ifndef BLINNPHONGMATERIAL_GLSL
 #define BLINNPHONGMATERIAL_GLSL
+// Blinn-Phong specular and exponent :
+// As this shader is built on Blinn-Phong NDF, that approximate Cook-Torrance,
+// Specular parameters from the asset must be converted so that specular highlight look the same than with
+// standard Phong BRDF (divided both Ks and Ns by Pi looks good).
+// See http://www.thetenthplanet.de/archives/255 for intuitions
 const float Pi = 3.141592653589793;
 
 struct BlinnPhongTextures

        return vec3(texture(material.tex.ks, texCoord));
    }

    return material.ks.xyz;
}

float getNs(Material material, vec2 texCoord)

        ns = texture(material.tex.ns, texCoord).r;
    }

    return max(ns, 0.001)/Pi; // Phong exponent to blinn-phong exponent
}

vec3 getNormal(Material material, vec2 texCoord, vec3 N, vec3 T, vec3 B)
