From d1f5ec7479eac5a3ad24dd0758560919e5fce03e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Mon, 14 May 2012 02:09:22 +0200
Subject: [PATCH] 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 | 3 ++-
 src/Shaders/PhongShader.vert | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/Shaders/PhongShader.frag b/src/Shaders/PhongShader.frag
index b70fb8f04..230af1736 100644
--- a/src/Shaders/PhongShader.frag
+++ b/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;
     }
 
diff --git a/src/Shaders/PhongShader.vert b/src/Shaders/PhongShader.vert
index 2a8ef00a0..5b73ccd79 100644
--- a/src/Shaders/PhongShader.vert
+++ b/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;
 }