// 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, double rad) {
    double 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, double v0, double v1) {
    double 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;
}