From a6a1c4dbb74c2c10baf4fef120a4206a3fd31b52 Mon Sep 17 00:00:00 2001
From: David Williams <david@volumesoffun.com>
Date: Thu, 29 May 2014 19:34:43 +0200
Subject: [PATCH] Getting ready to decode normal.

---
 examples/DecodeOnGPU/decode.frag | 4 ++--
 examples/DecodeOnGPU/decode.vert | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/examples/DecodeOnGPU/decode.frag b/examples/DecodeOnGPU/decode.frag
index c9cbf215..fb576125 100644
--- a/examples/DecodeOnGPU/decode.frag
+++ b/examples/DecodeOnGPU/decode.frag
@@ -11,9 +11,9 @@ 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)));
+	//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);
+	outputColor = vec4(abs(worldNormal.xyz) * 0.5 + vec3(0.5, 0.5, 0.5), 1.0);
 }
diff --git a/examples/DecodeOnGPU/decode.vert b/examples/DecodeOnGPU/decode.vert
index de61bc42..00675617 100644
--- a/examples/DecodeOnGPU/decode.vert
+++ b/examples/DecodeOnGPU/decode.vert
@@ -1,6 +1,7 @@
 #version 140
 
 in uvec4 position; // This will be the position of the vertex in model-space
+in vec4 normal;
 
 // The usual matrices are provided
 uniform mat4 cameraToClipMatrix;
@@ -10,12 +11,15 @@ uniform mat4 modelToWorldMatrix;
 // This will be used by the fragment shader to calculate flat-shaded normals. This is an unconventional approach
 // but we use it in this example framework because not all surface extractor generate surface normals.
 out vec4 worldPosition;
+out vec4 worldNormal;
 
 void main()
 {
 	vec4 decodedPosition = position;
 	decodedPosition.xyz = decodedPosition.xyz * (1.0 / 256.0);
 	
+	worldNormal = normal;
+	
 	// Standard sequence of OpenGL transformations.
 	worldPosition = modelToWorldMatrix * decodedPosition;
 	vec4 cameraPosition = worldToCameraMatrix * worldPosition;