Magic_Game/Easy2D/math/Matrix.hpp

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// Copyright (c) 2016-2018 Easy2D - Nomango
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#pragma once
#include "Vec2.hpp"
#include "Rect.hpp"
#include <algorithm>
namespace easy2d
{
namespace math
{
struct Matrix
{
union
{
struct
{
float m[6]; // m[3][2]
};
struct
{
float
_11, _12,
_21, _22,
_31, _32;
};
};
Matrix()
: _11(1.f), _12(0.f)
, _21(0.f), _22(1.f)
, _31(0.f), _32(0.f)
{
}
Matrix(float _11, float _12, float _21, float _22, float _31, float _32)
: _11(_11), _12(_12), _21(_21), _22(_22), _31(_31), _32(_32)
{
}
explicit Matrix(const float* p)
{
for (int i = 0; i < 6; i++)
m[i] = p[i];
}
Matrix(Matrix const& other)
: _11(other._11), _12(other._12)
, _21(other._21), _22(other._22)
, _31(other._31), _32(other._32)
{
}
template <typename T>
Matrix(T const& other)
{
for (int i = 0; i < 6; i++)
m[i] = other[i];
}
inline void Identity()
{
_11 = 1.f; _12 = 0.f;
_21 = 0.f; _12 = 1.f;
_31 = 0.f; _32 = 0.f;
}
inline Vec2 Transform(const Vec2& v) const
{
return Vec2(
v.x * _11 + v.y * _21 + _31,
v.x * _12 + v.y * _22 + _32
);
}
Rect Transform(const Rect & rect) const
{
Vec2 top_left = Transform(rect.GetLeftTop());
Vec2 top_right = Transform(rect.GetRightTop());
Vec2 bottom_left = Transform(rect.GetLeftBottom());
Vec2 bottom_right = Transform(rect.GetRightBottom());
float left = std::min(std::min(top_left.x, top_right.x), std::min(bottom_left.x, bottom_right.x));
float right = std::max(std::max(top_left.x, top_right.x), std::max(bottom_left.x, bottom_right.x));
float top = std::min(std::min(top_left.y, top_right.y), std::min(bottom_left.y, bottom_right.y));
float bottom = std::max(std::max(top_left.y, top_right.y), std::max(bottom_left.y, bottom_right.y));
return Rect{ left, top, (right - left), (bottom - top) };
}
inline void Translate(const Vec2& v)
{
_31 += _11 * v.x + _21 * v.y;
_32 += _12 * v.x + _22 * v.y;
}
inline float operator [](unsigned int index) const
{
return m[index];
}
template <typename T>
inline Matrix& operator =(T const& other)
{
for (int i = 0; i < 6; i++)
m[i] = other[i];
return *this;
}
inline float Determinant() const
{
return (_11 * _22) - (_12 * _21);
}
inline bool IsIdentity() const
{
return _11 == 1.f && _12 == 0.f &&
_21 == 0.f && _22 == 1.f &&
_31 == 0.f && _32 == 0.f;
}
inline bool IsInvertible() const
{
return 0 != Determinant();
}
static inline Matrix Translation(const Vec2& v)
{
return Matrix(
1.f, 0.f,
0.f, 1.f,
v.x, v.y
);
}
static inline Matrix Translation(
float x,
float y)
{
return Translation(Vec2(x, y));
}
static inline Matrix Scaling(
const Vec2& v,
const Vec2& center = Vec2())
{
return Matrix(
v.x, 0.f,
0.f, v.y,
center.x - v.x * center.x,
center.y - v.y * center.y
);
}
static inline Matrix Scaling(
float x,
float y,
const Vec2& center = Vec2())
{
return Scaling(Vec2(x, y), center);
}
static inline Matrix Rotation(
float angle,
const Vec2& center = Vec2())
{
float s = math::Sin(angle);
float c = math::Cos(angle);
return Matrix(
c, s,
-s, c,
center.x * (1 - c) + center.y * s,
center.y * (1 - c) - center.x * s
);
}
static inline Matrix Skewing(
float angle_x,
float angle_y,
const Vec2& center = Vec2())
{
float tx = math::Tan(angle_x);
float ty = math::Tan(angle_y);
return Matrix(
1.f, -ty,
-tx, 1.f,
center.y * tx, center.x * ty
);
}
static inline Matrix Invert(Matrix const& matrix)
{
float det = 1.f / matrix.Determinant();
return Matrix(
det * matrix._22,
-det * matrix._12,
-det * matrix._21,
det * matrix._11,
det * (matrix._21 * matrix._32 - matrix._22 * matrix._31),
det * (matrix._12 * matrix._31 - matrix._11 * matrix._32)
);
}
};
// Use template expression to optimize matrix multiply
template <typename L, typename R>
struct MatrixMultiply
{
L const& lhs;
R const& rhs;
MatrixMultiply(L const& lhs, R const& rhs)
: lhs(lhs)
, rhs(rhs)
{}
inline float operator [](unsigned int index) const
{
switch (index)
{
case 0:
return lhs[0] * rhs[0] + lhs[1] * rhs[2];
case 1:
return lhs[0] * rhs[1] + lhs[1] * rhs[3];
case 2:
return lhs[2] * rhs[0] + lhs[3] * rhs[2];
case 3:
return lhs[2] * rhs[1] + lhs[3] * rhs[3];
case 4:
return lhs[4] * rhs[0] + lhs[5] * rhs[2] + rhs[4];
case 5:
return lhs[4] * rhs[1] + lhs[5] * rhs[3] + rhs[5];
default:
return 0.f;
}
}
};
inline MatrixMultiply<Matrix, Matrix> operator *(Matrix const& lhs, Matrix const& rhs)
{
return MatrixMultiply<Matrix, Matrix>(lhs, rhs);
}
template <typename L, typename R>
inline MatrixMultiply<MatrixMultiply<L, R>, Matrix> operator *(MatrixMultiply<L, R> const& lhs, Matrix const& rhs)
{
return MatrixMultiply<MatrixMultiply<L, R>, Matrix>(lhs, rhs);
}
}
}