pocketpy/include/pocketpy/linalg.h

#pragma once

#include "bindings.h"

namespace pkpy{

inline bool isclose(float a, float b){ return std::fabs(a - b) < 1e-4; }

struct Vec2{
    static void _register(VM* vm, PyObject* mod, PyObject* type);

    float x, y;
    Vec2() : x(0.0f), y(0.0f) {}
    Vec2(float x, float y) : x(x), y(y) {}

    Vec2 operator+(const Vec2& v) const { return Vec2(x + v.x, y + v.y); }
    Vec2 operator-(const Vec2& v) const { return Vec2(x - v.x, y - v.y); }
    Vec2 operator*(float s) const { return Vec2(x * s, y * s); }
    Vec2 operator*(const Vec2& v) const { return Vec2(x * v.x, y * v.y); }
    Vec2 operator/(float s) const { return Vec2(x / s, y / s); }
    Vec2 operator-() const { return Vec2(-x, -y); }
    bool operator==(const Vec2& v) const { return isclose(x, v.x) && isclose(y, v.y); }
    bool operator!=(const Vec2& v) const { return !isclose(x, v.x) || !isclose(y, v.y); }
    float dot(const Vec2& v) const { return x * v.x + y * v.y; }
    float cross(const Vec2& v) const { return x * v.y - y * v.x; }
    float length() const { return sqrtf(x * x + y * y); }
    float length_squared() const { return x * x + y * y; }
    Vec2 normalize() const { float l = length(); return Vec2(x / l, y / l); }
    Vec2 rotate(float radian) const { float cr = cosf(radian), sr = sinf(radian); return Vec2(x * cr - y * sr, x * sr + y * cr); }
    NoReturn normalize_() { float l = length(); x /= l; y /= l; return {}; }
    NoReturn copy_(const Vec2& v) { x = v.x; y = v.y; return {}; }
};

struct Vec3{
    static void _register(VM* vm, PyObject* mod, PyObject* type);

    float x, y, z;
    Vec3() : x(0.0f), y(0.0f), z(0.0f) {}
    Vec3(float x, float y, float z) : x(x), y(y), z(z) {}

    Vec3 operator+(const Vec3& v) const { return Vec3(x + v.x, y + v.y, z + v.z); }
    Vec3 operator-(const Vec3& v) const { return Vec3(x - v.x, y - v.y, z - v.z); }
    Vec3 operator*(float s) const { return Vec3(x * s, y * s, z * s); }
    Vec3 operator*(const Vec3& v) const { return Vec3(x * v.x, y * v.y, z * v.z); }
    Vec3 operator/(float s) const { return Vec3(x / s, y / s, z / s); }
    Vec3 operator-() const { return Vec3(-x, -y, -z); }
    bool operator==(const Vec3& v) const { return isclose(x, v.x) && isclose(y, v.y) && isclose(z, v.z); }
    bool operator!=(const Vec3& v) const { return !isclose(x, v.x) || !isclose(y, v.y) || !isclose(z, v.z); }
    float dot(const Vec3& v) const { return x * v.x + y * v.y + z * v.z; }
    Vec3 cross(const Vec3& v) const { return Vec3(y * v.z - z * v.y, z * v.x - x * v.z, x * v.y - y * v.x); }
    float length() const { return sqrtf(x * x + y * y + z * z); }
    float length_squared() const { return x * x + y * y + z * z; }
    Vec3 normalize() const { float l = length(); return Vec3(x / l, y / l, z / l); }
    NoReturn normalize_() { float l = length(); x /= l; y /= l; z /= l; return {}; }
    NoReturn copy_(const Vec3& v) { x = v.x; y = v.y; z = v.z; return {}; }
};

struct Vec4{
    static void _register(VM* vm, PyObject* mod, PyObject* type);

    float x, y, z, w;
    Vec4() : x(0.0f), y(0.0f), z(0.0f), w(0.0f) {}
    Vec4(float x, float y, float z, float w) : x(x), y(y), z(z), w(w) {}

    Vec4 operator+(const Vec4& v) const { return Vec4(x + v.x, y + v.y, z + v.z, w + v.w); }
    Vec4 operator-(const Vec4& v) const { return Vec4(x - v.x, y - v.y, z - v.z, w - v.w); }
    Vec4 operator*(float s) const { return Vec4(x * s, y * s, z * s, w * s); }
    Vec4 operator*(const Vec4& v) const { return Vec4(x * v.x, y * v.y, z * v.z, w * v.w); }
    Vec4 operator/(float s) const { return Vec4(x / s, y / s, z / s, w / s); }
    Vec4 operator-() const { return Vec4(-x, -y, -z, -w); }
    bool operator==(const Vec4& v) const { return isclose(x, v.x) && isclose(y, v.y) && isclose(z, v.z) && isclose(w, v.w); }
    bool operator!=(const Vec4& v) const { return !isclose(x, v.x) || !isclose(y, v.y) || !isclose(z, v.z) || !isclose(w, v.w); }
    float dot(const Vec4& v) const { return x * v.x + y * v.y + z * v.z + w * v.w; }
    float length() const { return sqrtf(x * x + y * y + z * z + w * w); }
    float length_squared() const { return x * x + y * y + z * z + w * w; }
    Vec4 normalize() const { float l = length(); return Vec4(x / l, y / l, z / l, w / l); }
    NoReturn normalize_() { float l = length(); x /= l; y /= l; z /= l; w /= l; return {}; }
    NoReturn copy_(const Vec4& v) { x = v.x; y = v.y; z = v.z; w = v.w; return {}; }
};

struct Mat3x3{
    static void _register(VM* vm, PyObject* mod, PyObject* type);

    union {
        struct {
            float        _11, _12, _13;
            float        _21, _22, _23;
            float        _31, _32, _33;
        };
        float m[3][3];
        float v[9];
    };

    Mat3x3();
    Mat3x3(float, float, float, float, float, float, float, float, float);

    static Mat3x3 zeros();
    static Mat3x3 ones();
    static Mat3x3 identity();

    Mat3x3 operator+(const Mat3x3& other) const;
    Mat3x3 operator-(const Mat3x3& other) const;
    Mat3x3 operator*(float scalar) const;
    Mat3x3 operator/(float scalar) const;

    bool operator==(const Mat3x3& other) const;
    bool operator!=(const Mat3x3& other) const;
    
    Mat3x3 matmul(const Mat3x3& other) const;
    Vec3 matmul(const Vec3& other) const;

    float determinant() const;
    Mat3x3 transpose() const;
    bool inverse(Mat3x3& out) const;

    /*************** affine transformations ***************/
    static Mat3x3 trs(Vec2 t, float radian, Vec2 s);
    bool is_affine() const;
    Vec2 _t() const;
    float _r() const;
    Vec2 _s() const;
};

void add_module_linalg(VM* vm);

static_assert(sizeof(Py_<Mat3x3>) <= 64);
static_assert(std::is_trivially_copyable<Vec2>::value);
static_assert(std::is_trivially_copyable<Vec3>::value);
static_assert(std::is_trivially_copyable<Vec4>::value);
static_assert(std::is_trivially_copyable<Mat3x3>::value);

}   // namespace pkpy