#pragma once
#include <plot/core/types.hpp>

namespace plot::math {

/// Column-major 3x3 matrix of `f32`, the layout OpenGL expects for `mat3`
/// uniforms.
struct Mat3 {
  f32 m[9] = {1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f};

  static constexpr Mat3 identity() noexcept { return Mat3{}; }

  /// Column-major product `(*this) * rhs`.
  constexpr Mat3 operator*(const Mat3& rhs) const noexcept {
    Mat3 out{0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f};
    for (usize col = 0; col < 3; ++col) {
      for (usize row = 0; row < 3; ++row) {
        f32 acc = 0.0f;
        for (usize k = 0; k < 3; ++k) acc += m[k * 3 + row] * rhs.m[col * 3 + k];
        out.m[col * 3 + row] = acc;
      }
    }
    return out;
  }
};

}  // namespace plot::math

namespace plot {
using math::Mat3;
}