From a17ef2ca4cca423fafabe239017a433f86643794 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Fri, 18 Feb 2011 00:09:15 +0000
Subject: [PATCH] Implement float4x4::ortho() and float4x4::translate().

---
 src/matrix.cpp | 27 +++++++++++++++++++++++++++
 src/matrix.h   |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/src/matrix.cpp b/src/matrix.cpp
index e193fcb1..7cad978d 100644
--- a/src/matrix.cpp
+++ b/src/matrix.cpp
@@ -62,6 +62,24 @@ template<> float4x4 float4x4::invert() const
     return ret;
 }
 
+template<> float4x4 float4x4::ortho(float left, float right, float bottom,
+                                    float top, float near, float far)
+{
+    float invrl = (right != left) ? 1.0f / (right - left) : 0.0f;
+    float invtb = (top != bottom) ? 1.0f / (top - bottom) : 0.0f;
+    float invfn = (far != near) ? 1.0f / (far - near) : 0.0f;
+
+    float4x4 ret(0.0f);
+    ret[0][0] = 2.0f * invrl;
+    ret[1][1] = 2.0f * invtb;
+    ret[2][2] = -2.0f * invfn;
+    ret[3][0] = - (right + left) * invrl;
+    ret[3][1] = - (top + bottom) * invtb;
+    ret[3][2] = - (far + near) * invfn;
+    ret[3][3] = 1.0f;
+    return ret;
+}
+
 template<> float4x4 float4x4::frustum(float left, float right, float bottom,
                                       float top, float near, float far)
 {
@@ -89,3 +107,12 @@ template<> float4x4 float4x4::perspective(float theta, float width,
     return frustum(-near * t1, near * t1, -near * t2, near * t2, near, far);
 }
 
+template<> float4x4 float4x4::translate(float x, float y, float z)
+{
+    float4x4 ret(1.0f);
+    ret[3][0] = x;
+    ret[3][1] = y;
+    ret[3][2] = z;
+    return ret;
+}
+
diff --git a/src/matrix.h b/src/matrix.h
index afa39a9f..0f3b31ba 100644
--- a/src/matrix.h
+++ b/src/matrix.h
@@ -195,8 +195,10 @@ template <typename T> struct Mat4
     T det() const;
     Mat4<T> invert() const;
 
+    static Mat4<T> ortho(T left, T right, T bottom, T top, T near, T far);
     static Mat4<T> frustum(T left, T right, T bottom, T top, T near, T far);
     static Mat4<T> perspective(T theta, T width, T height, T near, T far);
+    static Mat4<T> translate(T x, T y, T z);
 
     inline Mat4<T> operator +(Mat4<T> const val) const
     {