Phong shader: finally fixed specular highlights.

The highlights are now based on camera position, which is finally the
way it should be since forever.

src/Shaders/PhongShader.frag

@@ -8,6 +8,7 @@ uniform float shininess = 80.0;
 
 in vec3 transformedNormal;
 in vec3 lightDirection;
+in vec3 cameraDirection;
 
 out vec4 color;
 
@@ -25,7 +26,7 @@ void main() {
     /* Add specular color, if needed */
     if(intensity != 0) {
         vec3 reflection = reflect(-normalizedLightDirection, normalizedTransformedNormal);
-        float specularity = pow(max(0.0, dot(normalizedTransformedNormal, reflection)), shininess);
+        float specularity = pow(max(0.0, dot(normalize(cameraDirection), reflection)), shininess);
         color.rgb += specularColor*specularity;
     }
 

src/Shaders/PhongShader.vert

@@ -9,6 +9,7 @@ in vec3 normal;
 
 out vec3 transformedNormal;
 out vec3 lightDirection;
+out vec3 cameraDirection;
 
 void main() {
     /* Transformed vertex position */
@@ -21,6 +22,9 @@ void main() {
     /* Direction to the light */
     lightDirection = normalize(light - transformedVertex);
 
+    /* Direction to the camera */
+    cameraDirection = -transformedVertex;
+
     /* Transform the vertex */
     gl_Position = projectionMatrix*transformedVertex4;
 }