port mat2 from gl-matrix

src/mbgl/util/mat2.cpp

@@ -0,0 +1,52 @@
+// 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/mat2.hpp>
+
+#include <cmath>
+
+using namespace mbgl;
+
+void matrix::identity(mat2& out) {
+    out[0] = 1.0f;
+    out[1] = 0.0f;
+    out[2] = 0.0f;
+    out[3] = 1.0f;
+}
+
+void matrix::rotate(mat2& out, const mat2& a, float rad) {
+    float a0 = a[0], a1 = a[1], a2 = a[2], a3 = a[3],
+        s = std::sin(rad),
+        c = std::cos(rad);
+    out[0] = a0 *  c + a2 * s;
+    out[1] = a1 *  c + a3 * s;
+    out[2] = a0 * -s + a2 * c;
+    out[3] = a1 * -s + a3 * c;
+};
+
+void matrix::scale(mat2& out, const mat2& a, float v0, float v1) {
+    float a0 = a[0], a1 = a[1], a2 = a[2], a3 = a[3];
+    out[0] = a0 * v0;
+    out[1] = a1 * v0;
+    out[2] = a2 * v1;
+    out[3] = a3 * v1;
+}

src/mbgl/util/mat2.hpp

@@ -0,0 +1,41 @@
+// 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.
+
+#ifndef MBGL_UTIL_MAT2
+#define MBGL_UTIL_MAT2
+
+#include <array>
+
+namespace mbgl {
+
+typedef std::array<float, 4> mat2;
+
+namespace matrix {
+
+void identity(mat2& out);
+void rotate(mat2& out, const mat2& a, float rad);
+void scale(mat2& out, const mat2& a, float v0, float v1);
+
+}
+}
+
+#endif