Common: Move Matrix classes out of MathUtil into their own files and make their interface more friendly.

Source/Core/Common/Matrix.h

@@ -0,0 +1,88 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+
+// Tiny matrix/vector library.
+// Used for things like Free-Look in the gfx backend.
+
+union Vec3
+{
+  Vec3() {}
+  Vec3(float _x, float _y, float _z) : data{_x, _y, _z} {}
+
+  std::array<float, 3> data = {};
+
+  struct
+  {
+    float x;
+    float y;
+    float z;
+  };
+};
+
+class Matrix33
+{
+public:
+  static Matrix33 Identity();
+
+  // Return a rotation matrix around the x,y,z axis
+  static Matrix33 RotateX(float rad);
+  static Matrix33 RotateY(float rad);
+  static Matrix33 RotateZ(float rad);
+
+  static Matrix33 Scale(const Vec3& vec);
+
+  // set result = a x b
+  static void Multiply(const Matrix33& a, const Matrix33& b, Matrix33* result);
+  static void Multiply(const Matrix33& a, const Vec3& vec, Vec3* result);
+
+  Matrix33& operator*=(const Matrix33& rhs)
+  {
+    Multiply(Matrix33(*this), rhs, this);
+    return *this;
+  }
+
+  std::array<float, 9> data;
+};
+
+inline Matrix33 operator*(Matrix33 lhs, const Matrix33& rhs)
+{
+  return lhs *= rhs;
+}
+
+inline Vec3 operator*(const Matrix33& lhs, const Vec3& rhs)
+{
+  Vec3 result;
+  Matrix33::Multiply(lhs, rhs, &result);
+  return result;
+}
+
+class Matrix44
+{
+public:
+  static Matrix44 Identity();
+  static Matrix44 FromMatrix33(const Matrix33& m33);
+  static Matrix44 FromArray(const float mtxArray[16]);
+
+  static Matrix44 Translate(const Vec3& vec);
+  static Matrix44 Shear(const float a, const float b = 0);
+
+  static void Multiply(const Matrix44& a, const Matrix44& b, Matrix44& result);
+
+  Matrix44& operator*=(const Matrix44& rhs)
+  {
+    Multiply(Matrix44(*this), rhs, *this);
+    return *this;
+  }
+
+  std::array<float, 16> data;
+};
+
+inline Matrix44 operator*(Matrix44 lhs, const Matrix44& rhs)
+{
+  return lhs *= rhs;
+}