Combine the environment mapping and bump mapping via a Fresnel factor.

1 files changed, 24 insertions, 4 deletions

diff --git a/src/phong.frag b/src/phong.frag
index 9bd054d..d2b74a3 100755
--- a/src/phong.frag
+++ b/src/phong.frag
@@ -14,6 +14,21 @@ const vec3 base_color = vec3(1.0, 0.0, 0.0);
  */
 uniform float s;
 
+float schlick(vec3 n, vec3 l)
+{
+	// Material constants... 1.0 = air, 3.5 = sphere (arbitrary)
+	const float ratio = 1.0 / 3.5;
+
+	// Value of the Fresnel reflection when N = L.
+	const float r0 = ((1 - ratio) * (1 - ratio)) / ((1 + ratio) * (1 + ratio));
+
+	/* According idr's slides on Fresnel reflection, page 45 and 47,
+	 * the input "theta" to the Frensel function is the angle between the
+	 * light and the normal vectors...so cos(theta) = dot(n, l).
+	 */
+	return r0 + (1 - r0) * pow(1.0 - dot(n, l), 5.0);
+}
+
 /* Adapted from the Orange Book, 3rd edition, chapter 11. */
 vec3 perturbed_normal()
 {
@@ -43,10 +58,15 @@ void main(void)
 	vec3 h = normalize(l + v);
 	vec3 n = perturbed_normal();
 	vec3 i = reflect(eye_ss, n);
-	//vec3 diff = vec3(textureCube(sampler, i));
-	vec3 diff = base_color * dot(n, l);
+	//vec3 diff = base_color * dot(n, l);
 	float spec = pow(dot(n, h), s);
 
-	gl_FragColor = step(0.0, dot(n, l)) * vec4(diff + vec3(spec), 1.0);
-	//gl_FragColor = textureCube(sampler, reflect(eye_direction_ws, normal_ws));
+	float F = schlick(n, l);
+
+	vec4 envir = textureCube(sampler, reflect(eye_direction_ws, normal_ws));
+	gl_FragColor = (1 - F) * envir + F * vec4(spec);
 }
+
+	//gl_FragColor = vec4((1 - F) * diff + F * vec3(spec), 1.0);
+	//gl_FragColor = step(0.0, dot(n, l)) * vec4(diff + vec3(spec), 1.0);
+	//gl_FragColor = textureCube(sampler, reflect(eye_direction_ws, normal_ws));