From 50789dee611da6db0ec36197053a8483ebd83d06 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Fri, 13 May 2011 15:05:25 -0400
Subject: [PATCH] add guMatrix3x3 and guMatrix4x4To3x3()

---
 glslUtil/glslUtil.c | 9 +++++++++
 glslUtil/glslUtil.h | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/glslUtil/glslUtil.c b/glslUtil/glslUtil.c
index bfc948f..8c925f5 100644
--- a/glslUtil/glslUtil.c
+++ b/glslUtil/glslUtil.c
@@ -190,6 +190,15 @@ void guMatrixOrtho(guMatrix4x4 *m,
     guMatrixMult(m, m, &mult);
 }
 
+void guMatrix4x4To3x3(guMatrix3x3 *out, const guMatrix4x4 *in)
+{
+    int i;
+    for (i = 0; i < 3; i++)
+    {
+        memcpy(&(*out)[i], &(*in)[i], sizeof((*out)[0][0] * 3));
+    }
+}
+
 char *guGetShaderLog(GLuint id)
 {
     GLint log_length;
diff --git a/glslUtil/glslUtil.h b/glslUtil/glslUtil.h
index e9d5292..a1d2b21 100644
--- a/glslUtil/glslUtil.h
+++ b/glslUtil/glslUtil.h
@@ -8,6 +8,7 @@
 #include <GL/gl.h>
 #endif
 
+typedef GLfloat guMatrix3x3[3][3];
 typedef GLfloat guMatrix4x4[4][4];
 typedef struct {
     GLuint index;
@@ -35,6 +36,8 @@ void guMatrixOrtho(guMatrix4x4 *m,
         GLfloat bottom, GLfloat top,
         GLfloat near, GLfloat far);
 
+void guMatrix4x4To3x3(guMatrix3x3 *out, const guMatrix4x4 *in);
+
 char *guGetShaderLog(GLuint id);
 char *guGetProgramLog(GLuint id);
 GLuint guMakeShaderFromFile(GLenum shaderType, const char *fname);