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diff --git a/src/mbgl/util/mat3.cpp b/src/mbgl/util/mat3.cpp
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+++ b/src/mbgl/util/mat3.cpp
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+// This is an incomplete port of http://glmatrix.net/
+//
+// Copyright (c) 2013 Brandon Jones, Colin MacKenzie IV
+//
+// This software is provided 'as-is', without any express or implied warranty.
+// In no event will the authors be held liable for any damages arising from the
+// use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not claim
+//    that you wrote the original software. If you use this software in a
+//    product, an acknowledgment in the product documentation would be
+//    appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not be
+//    misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+
+#include <mbgl/util/mat3.hpp>
+
+#include <cmath>
+
+using namespace mbgl;
+
+void matrix::identity(mat3& out) {
+    out[0] = 1.0f;
+    out[1] = 0.0f;
+    out[2] = 0.0f;
+    out[3] = 0.0f;
+    out[4] = 1.0f;
+    out[5] = 0.0f;
+    out[6] = 0.0f;
+    out[7] = 0.0f;
+    out[8] = 1.0f;
+}
+
+void matrix::translate(mat3& out, const mat3& a, float x, float y) {
+    float a00 = a[0], a01 = a[1], a02 = a[2],
+          a10 = a[3], a11 = a[4], a12 = a[5],
+          a20 = a[6], a21 = a[7], a22 = a[8];
+
+    out[0] = a00;
+    out[1] = a01;
+    out[2] = a02;
+
+    out[3] = a10;
+    out[4] = a11;
+    out[5] = a12;
+
+    out[6] = x * a00 + y * a10 + a20;
+    out[7] = x * a01 + y * a11 + a21;
+    out[8] = x * a02 + y * a12 + a22;
+}
+
+void matrix::rotate(mat3& out, const mat3& a, float rad) {
+    float s = std::sin(rad),
+          c = std::cos(rad),
+          a00 = a[0],
+          a01 = a[1],
+          a02 = a[2],
+          a10 = a[3],
+          a11 = a[4],
+          a12 = a[5],
+          a20 = a[6],
+          a21 = a[7],
+          a22 = a[8];
+
+    out[0] = c * a00 + s * a10;
+    out[1] = c * a01 + s * a11;
+    out[2] = c * a02 + s * a12;
+
+    out[3] = c * a10 - s * a00;
+    out[4] = c * a11 - s * a01;
+    out[5] = c * a12 - s * a02;
+
+    out[6] = a20;
+    out[7] = a21;
+    out[8] = a22;
+};
+
+void matrix::scale(mat3& out, const mat3& a, float x, float y) {
+    out[0] = x * a[0];
+    out[1] = x * a[1];
+    out[2] = x * a[2];
+    out[3] = y * a[3];
+    out[4] = y * a[4];
+    out[5] = y * a[5];
+    out[6] = a[6];
+    out[7] = a[7];
+    out[8] = a[8];
+}