palladium/pd/core/source/mat.cpp

/*
MIT License

Copyright (c) 2024 - 2025 tobid7

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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*/

#include <pd/core/mat.hpp>

namespace PD {
PD_CORE_API Mat4 Mat4::RotateX(float a) {
  float c = std::cos(a);
  float s = std::sin(a);
  Mat4 ret = Identity();
  ret(1, 1) = c;
  ret(1, 2) = -s;
  ret(2, 1) = s;
  ret(2, 2) = c;
  return ret;
}

PD_CORE_API Mat4 Mat4::RotateY(float a) {
  float c = std::cos(a);
  float s = std::sin(a);
  Mat4 ret = Identity();
  ret(0, 0) = c;
  ret(0, 2) = s;
  ret(2, 0) = -s;
  ret(2, 2) = c;
  return ret;
}

PD_CORE_API Mat4 Mat4::RotateZ(float a) {
  float c = std::cos(a);
  float s = std::sin(a);
  Mat4 ret = Identity();
  ret(0, 0) = c;
  ret(0, 1) = -s;
  ret(1, 0) = s;
  ret(1, 1) = c;
  return ret;
}

PD_CORE_API Mat4 Mat4::Rotate(fvec3 axis, float a) {
  float s = std::sin(a);
  float c = std::cos(a);
  float t = 1.f - c;
  axis = axis.Normalize();
  float x = axis.x;
  float y = axis.y;
  float z = axis.z;
  Mat4 ret = Identity();
  ret(0, 0) = t * x * x + c;
  ret(0, 1) = t * x * y - z * s;
  ret(0, 2) = t * x * z + y * s;

  ret(1, 0) = t * x * y + z * s;
  ret(1, 1) = t * y * y + c;
  ret(1, 2) = t * y * z - x * s;

  ret(2, 0) = t * x * z - y * s;
  ret(2, 1) = t * y * z + x * s;
  ret(2, 2) = t * z * z + c;
  return ret;
}

PD_CORE_API Mat4 Mat4::Perspective(float fov, float aspect, float n, float f) {
  float _fov = std::tan(fov / 2.f);
  Mat4 ret;
  ret(0, 0) = 1.f / (aspect * _fov);
  ret(1, 1) = 1.f / _fov;
#ifdef __3DS__
  ret(2, 3) = f * n / (n - f);
  ret(2, 2) = -(-1.f) * n / (n - f);
#else
  ret(2, 2) = -(f + n) / (f - n);
  ret(2, 3) = -(2.f * f * n) / (f - n);
#endif
  ret(3, 2) = -1.f;
  ret(3, 3) = 0.0f;
  return ret;
}

PD_CORE_API Mat4 Mat4::LookAt(const fvec3& pos, const fvec3& center,
                              const fvec3& up) {
  auto f = fvec3(center - pos).Normalize();
  auto s = f.Cross(up).Normalize();
  auto u = s.Cross(f);

  Mat4 ret = Identity();
  ret(0, 0) = s.x;
  ret(0, 1) = s.y;
  ret(0, 2) = s.z;
  ret(1, 0) = u.x;
  ret(1, 1) = u.y;
  ret(1, 2) = u.z;
  ret(2, 0) = -f.x;
  ret(2, 1) = -f.y;
  ret(2, 2) = -f.z;
  ret(0, 3) = -s.Dot(pos);
  ret(1, 3) = -u.Dot(pos);
  ret(2, 3) = f.Dot(pos);
  return ret;
}
}  // namespace PD