Optimized shaders

shader/light.frag

@@ -7,33 +7,31 @@ varying vec3 normal, pos;
 void main() {
   vec3 n, l, refl, eye;
   float NdotL, RdotE;
-  vec4 color, specularColor;
-  float dist, att, specularFactor;
+  vec4 specularColor;
+  float dist, distSq, att, specularFactor;
   
   n = normalize(normal);
   
   l = gl_LightSource[0].position.xyz - pos;
   
-  dist = length(l);
-  l /= dist;
+  distSq = dot(l, l);
   
-  /* compute the dot product between normal and normalized lightdir */
-  NdotL = max(dot(n, l), 0.0);
+  NdotL = dot(n, l);
 
   if (NdotL > 0.0) {
-    att = 1.0 / (gl_LightSource[0].constantAttenuation +
-        gl_LightSource[0].linearAttenuation * dist +
-        gl_LightSource[0].quadraticAttenuation * dist * dist);
-    color = att * (diffuse * NdotL + ambient);
+    dist = sqrt(distSq);
     
-    refl = normalize(reflect(-l, n));
-    eye = normalize(-pos);
+    att = 1.0 / (gl_LightSource[0].quadraticAttenuation * distSq);
+    gl_FragColor = att * (diffuse * NdotL / dist + ambient) * texture2D(tex, gl_TexCoord[0].st);
     
-    RdotE = max(dot(refl, eye), 0.0);
+    refl = reflect(-l, n);
+    
+    RdotE = -dot(refl, pos) / sqrt(dot(refl, refl) * dot(pos, pos));
+    
+    if(RdotE > 0.0) {
       specularFactor = att * pow(RdotE, gl_FrontMaterial.shininess);
-    specularColor = specularFactor * gl_FrontMaterial.specular * gl_LightSource[0].specular;
-    
-    gl_FragColor = color * texture2D(tex, gl_TexCoord[0].st) + specularColor;
+      gl_FragColor += specularFactor * gl_FrontMaterial.specular * gl_LightSource[0].specular;
+    }
   }
   else {
     gl_FragColor = vec4(0, 0, 0, 1);

shader/light.vert

@@ -3,7 +3,7 @@ varying vec3 normal, pos;
 
 
 void main() {
-  normal = normalize(gl_NormalMatrix * gl_Normal);
+  normal = gl_NormalMatrix * gl_Normal;
   
   pos = vec3(gl_ModelViewMatrix * gl_Vertex);