diff --git a/Shaders/bumpspec.frag b/Shaders/bumpspec.frag
index b708746eb..16f8d161c 100644
--- a/Shaders/bumpspec.frag
+++ b/Shaders/bumpspec.frag
@@ -2,11 +2,11 @@
 // Licence: GPL v2
 // Author: Frederic Bouvier
 
-varying vec4 ecPosition;
+varying float fogCoord;
+
 varying vec3 VNormal;
 varying vec3 VTangent;
 varying vec3 VBinormal;
-varying vec4 constantColor;
 
 uniform sampler2D tex_color;
 uniform sampler2D tex_normal;
@@ -29,7 +29,7 @@ void main (void)
 	vec4 Diffuse  = gl_LightSource[0].diffuse * nDotVP;
 	vec4 Specular = gl_LightSource[0].specular * pf;
 
-	vec4 color = constantColor + Diffuse * gl_FrontMaterial.diffuse;
+	vec4 color = gl_Color + Diffuse * gl_FrontMaterial.diffuse;
 	color *= texture2D(tex_color, gl_TexCoord[0].xy);
 
 	color += Specular * gl_FrontMaterial.specular * ns.a;
@@ -37,7 +37,6 @@ void main (void)
 
 
 	float fogFactor;
-	float fogCoord = ecPosition.z;
 	const float LOG2 = 1.442695;
 	fogFactor = exp2(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord * LOG2);
 	fogFactor = clamp(fogFactor, 0.0, 1.0);
diff --git a/Shaders/bumpspec.vert b/Shaders/bumpspec.vert
index 4ed1b8a59..d7b7a8974 100644
--- a/Shaders/bumpspec.vert
+++ b/Shaders/bumpspec.vert
@@ -2,23 +2,24 @@
 // Licence: GPL v2
 // Author: Frederic Bouvier
 
-varying vec4 ecPosition;
+varying float fogCoord;
 varying vec3 VNormal;
 varying vec3 VTangent;
 varying vec3 VBinormal;
-varying vec4 constantColor;
 
 attribute vec3 tangent;
 attribute vec3 binormal;
 
 void main (void)
 {
-	ecPosition = gl_ModelViewMatrix * gl_Vertex;
+	vec4 pos = gl_ModelViewMatrix * gl_Vertex;
+        fogCoord = pos.z / pos.w;
+
 	VNormal = normalize(gl_NormalMatrix * gl_Normal);
 	VTangent = normalize(gl_NormalMatrix * tangent);
 	VBinormal = normalize(gl_NormalMatrix * binormal);
-	constantColor = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;
-	gl_FrontColor = constantColor;
+
+	gl_FrontColor = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;
 	gl_TexCoord[0] = gl_MultiTexCoord0;
 	gl_Position = ftransform();
 }
diff --git a/Shaders/default.frag b/Shaders/default.frag
index 3b01a6676..52afbaf2d 100644
--- a/Shaders/default.frag
+++ b/Shaders/default.frag
@@ -14,7 +14,7 @@ float luminance(vec3 color)
 
 void main()
 {
-    vec3 n, halfV;
+    vec3 n;
     float NdotL, NdotHV, fogFactor;
     vec4 color = gl_Color;
     vec3 lightDir = gl_LightSource[0].position.xyz;
@@ -22,16 +22,16 @@ void main()
     vec4 texel;
     vec4 fragColor;
     vec4 specular = vec4(0.0);
-    n = normalize(normal);
+
     // If gl_Color.a == 0, this is a back-facing polygon and the
     // normal should be reversed.
+    n = (2.0 * gl_Color.a - 1.0) * normal;
+    n = normalize(n);
 
-    n = (2.0 * gl_Color.a - 1.0) * n;
-    NdotL = max(dot(n, lightDir), 0.0);
+    NdotL = dot(n, lightDir);
     if (NdotL > 0.0) {
         color += diffuse_term * NdotL;
-        halfV = halfVector;
-        NdotHV = max(dot(n, halfV), 0.0);
+        NdotHV = max(dot(n, halfVector), 0.0);
         if (gl_FrontMaterial.shininess > 0.0)
             specular.rgb = (gl_FrontMaterial.specular.rgb
                             * gl_LightSource[0].specular.rgb
diff --git a/Shaders/model-default.frag b/Shaders/model-default.frag
index 5ed50a642..2c94b92d0 100644
--- a/Shaders/model-default.frag
+++ b/Shaders/model-default.frag
@@ -22,11 +22,11 @@ void main()
     vec4 texel;
     vec4 fragColor;
     vec4 specular = vec4(0.0);
-    n = normalize(normal);
     // If gl_Color.a == 0, this is a back-facing polygon and the
     // normal should be reversed.
-    n = (2.0 * gl_Color.a - 1.0) * n;
-    NdotL = max(dot(n, lightDir), 0.0);
+    n = (2.0 * gl_Color.a - 1.0) * normal;
+    n = normalize(n);
+    NdotL = dot(n, lightDir);
     if (NdotL > 0.0) {
         color += diffuse_term * NdotL;
         halfV = normalize(halfVector);
diff --git a/Shaders/reflect-bump-spec.frag b/Shaders/reflect-bump-spec.frag
index 859d21e40..70a6c1a60 100644
--- a/Shaders/reflect-bump-spec.frag
+++ b/Shaders/reflect-bump-spec.frag
@@ -4,19 +4,17 @@
 
 #version 120
 
-varying vec4  rawpos;
-varying vec4  ecPosition;
+varying vec3  rawpos;
 varying vec3  VNormal;
 varying vec3  VTangent;
 varying vec3  VBinormal;
 varying vec3  Normal;
-varying vec4  constantColor;
 varying vec3  vViewVec;
 varying vec3  reflVec;
 
 varying vec4 Diffuse;
-varying vec3 lightDir, halfVector;
-varying float alpha, fogCoord;
+varying float alpha;
+varying float fogCoord;
 
 uniform samplerCube Environment;
 uniform sampler2D Rainbow;
@@ -37,7 +35,12 @@ void main (void)
 {
     vec3 halfV;
     float NdotL, NdotHV;
-    vec4 color = constantColor;
+
+    vec3 lightDir = gl_LightSource[0].position.xyz;
+    vec3 halfVector = gl_LightSource[0].halfVector.xyz;
+
+
+    vec4 color = gl_Color;
     vec4 specular = vec4(0.0);
     vec4 ns = texture2D(NormalTex, gl_TexCoord[0].st);
     vec3 n = ns.rgb * 2.0 - 1.0;
@@ -61,7 +64,6 @@ void main (void)
     vec4 texelcolor = color * texel + specular;
 
     // calculate the fog factor
-    float fogCoord = ecPosition.z;
     const float LOG2 = 1.442695;
     float fogFactor = exp2(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord * LOG2);
     fogFactor = clamp(fogFactor, 0.0, 1.0);
diff --git a/Shaders/reflect-bump-spec.vert b/Shaders/reflect-bump-spec.vert
index d2b7e9ff2..6eb1a68db 100644
--- a/Shaders/reflect-bump-spec.vert
+++ b/Shaders/reflect-bump-spec.vert
@@ -2,19 +2,17 @@
 // Licence: GPL v2
 // Author: Vivian Meazza.
 
-varying vec4  rawpos;
-varying vec4  ecPosition;
+varying vec3  rawpos;
+varying float fogCoord;
 varying vec3  VNormal;
 varying vec3  VTangent;
 varying vec3  VBinormal;
 varying vec3  Normal;
-varying vec4  constantColor;
 varying vec3 vViewVec;
 varying vec3 reflVec;
 
 varying vec4 Diffuse;
-varying vec3 normal, lightDir, halfVector;
-varying float alpha, fogCoord;
+varying float alpha;
 
 uniform mat4 osg_ViewMatrixInverse;
 
@@ -23,23 +21,23 @@ attribute vec3 binormal;
 
 void main(void)
 {
-    rawpos     = gl_Vertex;
-    ecPosition = gl_ModelViewMatrix * gl_Vertex;
-    vec3 ecPosition3 = vec3(gl_ModelViewMatrix * gl_Vertex) / ecPosition.w;
+    rawpos     = gl_Vertex.xyz / gl_Vertex.w;
+    vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
+    ecPosition.xyz = ecPosition.xyz / ecPosition.w;
+    fogCoord = ecPosition.z;
 
-    vec3 t = normalize(cross(gl_Normal, vec3(1.0,0.0,0.0)));
-    vec3 b = normalize(cross(gl_Normal,t));
     vec3 n = normalize(gl_Normal);
+    vec3 t = cross(gl_Normal, vec3(1.0,0.0,0.0));
+    vec3 b = cross(n,t);
 
     VNormal = normalize(gl_NormalMatrix * gl_Normal);
-	VTangent = normalize(gl_NormalMatrix * tangent);
-	VBinormal = normalize(gl_NormalMatrix * binormal);
+    VTangent = normalize(gl_NormalMatrix * tangent);
+    VBinormal = normalize(gl_NormalMatrix * binormal);
     Normal = normalize(gl_Normal);
 
-    lightDir = normalize(vec3(gl_LightSource[0].position));
-    halfVector = normalize(gl_LightSource[0].halfVector.xyz);
     Diffuse = gl_Color * gl_LightSource[0].diffuse;
     //Diffuse= gl_Color.rgb * max(0.0, dot(normalize(VNormal), gl_LightSource[0].position.xyz));
+
     // Super hack: if diffuse material alpha is less than 1, assume a
     // transparency animation is at work
     if (gl_FrontMaterial.diffuse.a < 1.0)
@@ -47,8 +45,6 @@ void main(void)
     else
         alpha = gl_Color.a;
 
-    fogCoord = abs(ecPosition3.z);
-
     // Vertex in eye coordinates
     vec3 vertVec = ecPosition.xyz;
 
@@ -60,10 +56,8 @@ void main(void)
     vec4 reflect_eye = vec4(reflect(vertVec, VNormal), 0.0);
     reflVec = normalize(gl_ModelViewMatrixInverse * reflect_eye).xyz;
 
-    gl_FrontColor = gl_Color;
-    constantColor = gl_FrontMaterial.emission
-        + gl_Color * (gl_LightModel.ambient + gl_LightSource[0].ambient);
+    gl_FrontColor = gl_FrontMaterial.emission + gl_Color * (gl_LightModel.ambient + gl_LightSource[0].ambient);
 
     gl_Position = ftransform();
     gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
-}
\ No newline at end of file
+}
diff --git a/Shaders/reflect.frag b/Shaders/reflect.frag
index 1f7fb6924..d1424b478 100644
--- a/Shaders/reflect.frag
+++ b/Shaders/reflect.frag
@@ -4,17 +4,15 @@
 
 #version 120
 
-varying vec4  rawpos;
-varying vec4  ecPosition;
+varying vec3  rawpos;
 varying vec3  VNormal;
-varying vec3  Normal;
 varying vec4  constantColor;
 varying vec3  vViewVec;
 varying vec3  reflVec;
 
 varying vec4 Diffuse;
-varying vec3 lightDir, halfVector;
-varying float alpha, fogCoord;
+varying float alpha;
+varying float fogCoord;
 
 uniform samplerCube Environment;
 uniform sampler2D Rainbow;
@@ -36,8 +34,11 @@ void main (void)
     float NdotL, NdotHV;
     vec4 color = constantColor;
     vec4 specular = vec4(0.0);
-    n = VNormal;
-    NdotL = max(0.0, dot(n, lightDir));
+    n = normalize(VNormal);
+    vec3 lightDir = gl_LightSource[0].position.xyz;
+    vec3 halfVector = gl_LightSource[0].halfVector.xyz;
+
+    NdotL = dot(n, lightDir);
 
     // calculate the specular light
     if (NdotL > 0.0) {
@@ -56,7 +57,6 @@ void main (void)
     vec4 texelcolor = color * texel + specular;
 
     // calculate the fog factor
-    float fogCoord = ecPosition.z;
     const float LOG2 = 1.442695;
     float fogFactor = exp2(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord * LOG2);
     fogFactor = clamp(fogFactor, 0.0, 1.0);
diff --git a/Shaders/reflect.vert b/Shaders/reflect.vert
index ed76cee0f..4c8928120 100644
--- a/Shaders/reflect.vert
+++ b/Shaders/reflect.vert
@@ -2,17 +2,15 @@
 // Licence: GPL v2
 // Author: Vivian Meazza.
 
-varying vec4  rawpos;
-varying vec4  ecPosition;
+varying vec3  rawpos;
 varying vec3  VNormal;
-varying vec3  Normal;
 varying vec4  constantColor;
 varying vec3 vViewVec;
 varying vec3 reflVec;
 
 varying vec4 Diffuse;
-varying vec3 normal, lightDir, halfVector;
-varying float alpha, fogCoord;
+varying float alpha;
+varying float fogCoord;
 
 uniform mat4 osg_ViewMatrixInverse;
 
@@ -20,19 +18,16 @@ uniform mat4 osg_ViewMatrixInverse;
 
 void main(void)
 {
-    rawpos     = gl_Vertex;
-    ecPosition = gl_ModelViewMatrix * gl_Vertex;
-    vec3 ecPosition3 = vec3(gl_ModelViewMatrix * gl_Vertex) / ecPosition.w;
+    rawpos     = gl_Vertex.xyz / gl_Vertex.w;
+    vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
+    ecPosition.xyz = ecPosition.xyz / ecPosition.w;
 
     vec3 t = normalize(cross(gl_Normal, vec3(1.0,0.0,0.0)));
     vec3 b = normalize(cross(gl_Normal,t));
     vec3 n = normalize(gl_Normal);
 
     VNormal = normalize(gl_NormalMatrix * gl_Normal);
-    Normal = normalize(gl_Normal);
 
-    lightDir = normalize(vec3(gl_LightSource[0].position));
-    halfVector = normalize(gl_LightSource[0].halfVector.xyz);
     Diffuse = gl_Color * gl_LightSource[0].diffuse;
     //Diffuse= gl_Color.rgb * max(0.0, dot(normalize(VNormal), gl_LightSource[0].position.xyz));
     // Super hack: if diffuse material alpha is less than 1, assume a
@@ -42,7 +37,7 @@ void main(void)
     else
         alpha = gl_Color.a;
 
-    fogCoord = abs(ecPosition3.z);
+    fogCoord = abs(ecPosition.z);
 
     // Vertex in eye coordinates
     vec3 vertVec = ecPosition.xyz;
@@ -61,4 +56,4 @@ void main(void)
 
     gl_Position = ftransform();
     gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
-}
\ No newline at end of file
+}