diff --git a/glslUtil/glslUtil.c b/glslUtil/glslUtil.c
index 74bc47d..c1ab190 100644
--- a/glslUtil/glslUtil.c
+++ b/glslUtil/glslUtil.c
@@ -35,3 +35,26 @@ void guMatrixTranslate(guMatrix4x4 *m, float x, float y, float z)
         m[i][3] += m[i][0] * x + m[i][1] * y + m[i][2] * z;
     }
 }
+
+void guMatrixFrustum(guMatrix4x4 *m,
+        float left, float right,
+        float bottom, float top,
+        float near, float far)
+{
+    guMatrix4x4 mult;
+    for (int i = 0; i < 4; i++)
+    {
+        for (int j = 0; j < 4; j++)
+        {
+            mult[i][j] = 0.0;
+        }
+    }
+    mult[0][0] = 2 * near / (right - left);
+    mult[0][2] = (right + left) / (right - left);
+    mult[1][1] = 2 * near / (top - bottom);
+    mult[1][2] = (top + bottom) / (top - bottom);
+    mult[2][2] = - (far + near) / (far - near);
+    mult[2][3] = - 2 * far * near / (far - near);
+    mult[3][2] = -1.0;
+    guMatrixMult(m, &mult);
+}
diff --git a/glslUtil/glslUtil.h b/glslUtil/glslUtil.h
index 3a29c7d..d976f16 100644
--- a/glslUtil/glslUtil.h
+++ b/glslUtil/glslUtil.h
@@ -17,6 +17,10 @@ extern "C" {
 void guMatrixLoadIdentity(guMatrix4x4 *m);
 void guMatrixMult(guMatrix4x4 *m, guMatrix4x4 *a, guMatrix4x4 *b);
 void guMatrixTranslate(guMatrix4x4 *m, float x, float y, float z);
+void guMatrixFrustum(guMatrix4x4 *m,
+        float left, float right,
+        float bottom, float top,
+        float near, float far);
 
 #ifdef __cplusplus
 }