include/rive/math/vec2d.hpp

#ifndef _RIVE_VEC2D_HPP_
#define _RIVE_VEC2D_HPP_

#include "rive/rive_types.hpp"

namespace rive
{
class Mat2D;
class Vec2D
{
public:
    float x, y;

    Vec2D() = default;
    constexpr Vec2D(float x, float y) : x(x), y(y) {}

    float lengthSquared() const { return x * x + y * y; }
    float length() const;
    Vec2D normalized() const;

    // Normalize this Vec, and return its previous length
    float normalizeLength()
    {
        const float len = this->length();
        if (len > 0)
        {
            x /= len;
            y /= len;
        }
        return len;
    }

    Vec2D operator-() const { return {-x, -y}; }

    void operator*=(float s)
    {
        x *= s;
        y *= s;
    }

    void operator/=(float s)
    {
        x /= s;
        y /= s;
    }

    friend inline Vec2D operator-(const Vec2D& a, const Vec2D& b)
    {
        return {a.x - b.x, a.y - b.y};
    }

    static inline Vec2D lerp(Vec2D a, Vec2D b, float f);

    static Vec2D transformDir(const Vec2D& a, const Mat2D& m);
    static Vec2D transformMat2D(const Vec2D& a, const Mat2D& m);

    static float dot(Vec2D a, Vec2D b) { return a.x * b.x + a.y * b.y; }
    static float cross(Vec2D a, Vec2D b) { return a.x * b.y - a.y * b.x; }
    static Vec2D scaleAndAdd(Vec2D a, Vec2D b, float scale)
    {
        return {
            a.x + b.x * scale,
            a.y + b.y * scale,
        };
    }
    static float distance(const Vec2D& a, const Vec2D& b)
    {
        return (a - b).length();
    }
    static float distanceSquared(const Vec2D& a, const Vec2D& b)
    {
        return (a - b).lengthSquared();
    }

    Vec2D& operator+=(Vec2D v)
    {
        x += v.x;
        y += v.y;
        return *this;
    }
    Vec2D& operator-=(Vec2D v)
    {
        x -= v.x;
        y -= v.y;
        return *this;
    }

    float operator[](size_t index) const
    {
        switch (index)
        {
            case 0:
                return x;
            case 1:
                return y;
            default:
                RIVE_UNREACHABLE();
        }
    }
};
static_assert(std::is_pod<Vec2D>::value, "Vec2D must be plain-old-data");

inline Vec2D operator*(const Vec2D& v, float s) { return {v.x * s, v.y * s}; }
inline Vec2D operator*(float s, const Vec2D& v) { return {v.x * s, v.y * s}; }
inline Vec2D operator/(const Vec2D& v, float s) { return {v.x / s, v.y / s}; }

inline Vec2D operator+(const Vec2D& a, const Vec2D& b)
{
    return {a.x + b.x, a.y + b.y};
}

inline bool operator==(const Vec2D& a, const Vec2D& b)
{
    return a.x == b.x && a.y == b.y;
}
inline bool operator!=(const Vec2D& a, const Vec2D& b)
{
    return a.x != b.x || a.y != b.y;
}

Vec2D Vec2D::lerp(Vec2D a, Vec2D b, float t) { return a + (b - a) * t; }

} // namespace rive

namespace std
{
template <> struct hash<rive::Vec2D>
{
    size_t operator()(const rive::Vec2D& v) const
    {
        // Combine the hashes of x and y to produce a hash for Vec2D
        size_t h1 = std::hash<float>()(v.x); // Hash for x component
        size_t h2 = std::hash<float>()(v.y); // Hash for y component
        return h1 ^ (h2 << 1); // Combine them with bitwise XOR and shift
    }
};
} // namespace std

#endif