From c3cc53d5aa6ed94d915998913ae10c552fabe20c Mon Sep 17 00:00:00 2001
From: Erwin Coumans <erwin.coumans@gmail.com>
Date: Thu, 13 Apr 2017 11:06:38 -0700
Subject: [PATCH] TinyRenderer, apply backface culling

---
 examples/TinyRenderer/TinyRenderer.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/examples/TinyRenderer/TinyRenderer.cpp b/examples/TinyRenderer/TinyRenderer.cpp
index a8494fa90..ed472a1f5 100644
--- a/examples/TinyRenderer/TinyRenderer.cpp
+++ b/examples/TinyRenderer/TinyRenderer.cpp
@@ -424,6 +424,16 @@ static void clipEdge(const mat<4,3,float>& triangleIn, int vertexIndexA, int ver
 
 static bool clipTriangleAgainstNearplane(const mat<4,3,float>& triangleIn, b3AlignedObjectArray<mat<4,3,float> >& clippedTrianglesOut)
 {
+
+
+	float orientation = (triangleIn[0][1] - triangleIn[0][0]) * (triangleIn[1][2] - triangleIn[1][0]) 
+	- (triangleIn[1][1] - triangleIn[1][0]) * (triangleIn[0][2] - triangleIn[0][0]);
+	
+	if (orientation < 0.0) 
+	{
+		return true;
+	}
+
 	//discard triangle if all vertices are behind near-plane
 	if (triangleIn[3][0]<0 && triangleIn[3][1] <0 && triangleIn[3][2] <0)
 	{