Added functions to perform 'octahedral' encoding and decoding of normals.

See http://jcgt.org/published/0003/02/01/paper-lowres.pdf

examples/common/example.frag

@@ -1,19 +1,19 @@
-#version 130
-
-// Passed in from the vertex shader
-in vec4 worldPosition;
-in vec4 worldNormal;
-
-// the color that gets written to the display
-out vec4 outputColor;
-
-void main()
-{
-	// Again, for the purposes of these examples we cannot be sure that per-vertex normals are provided. A sensible fallback 
-	// is to use this little trick to compute per-fragment flat-shaded normals from the world positions using derivative operations.
-	vec3 normal = normalize(cross(dFdy(worldPosition.xyz), dFdx(worldPosition.xyz)));
-	
-	// We are just using the normal as the output color, and making it lighter so it looks a bit nicer. 
-	// Obviously a real shader would also do texuring, lighting, or whatever is required for the application.
-	outputColor = vec4(abs(normal) * 0.5 + vec3(0.5, 0.5, 0.5), 1.0);
-}
+#version 130
+
+// Passed in from the vertex shader
+in vec4 worldPosition;
+in vec3 worldNormal;
+
+// the color that gets written to the display
+out vec4 outputColor;
+
+void main()
+{
+	// Again, for the purposes of these examples we cannot be sure that per-vertex normals are provided. A sensible fallback 
+	// is to use this little trick to compute per-fragment flat-shaded normals from the world positions using derivative operations.
+	vec3 normal = normalize(cross(dFdy(worldPosition.xyz), dFdx(worldPosition.xyz)));
+	
+	// We are just using the normal as the output color, and making it lighter so it looks a bit nicer. 
+	// Obviously a real shader would also do texuring, lighting, or whatever is required for the application.
+	outputColor = vec4(abs(worldNormal.xyz), 1.0);
+}