87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
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#pragma once
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#include <cmath>
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namespace extra2d {
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// ---------------------------------------------------------------------------
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// 常量
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// ---------------------------------------------------------------------------
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constexpr float PI_F = 3.14159265358979323846f;
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constexpr float DEG_TO_RAD = PI_F / 180.0f;
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constexpr float RAD_TO_DEG = 180.0f / PI_F;
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// ---------------------------------------------------------------------------
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// 2D 向量
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// ---------------------------------------------------------------------------
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struct Vec2 {
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float x = 0.0f;
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float y = 0.0f;
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constexpr Vec2() = default;
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constexpr Vec2(float x, float y) : x(x), y(y) {}
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// 基础运算
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Vec2 operator+(const Vec2 &v) const { return {x + v.x, y + v.y}; }
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Vec2 operator-(const Vec2 &v) const { return {x - v.x, y - v.y}; }
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Vec2 operator*(float s) const { return {x * s, y * s}; }
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Vec2 operator/(float s) const { return {x / s, y / s}; }
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Vec2 operator-() const { return {-x, -y}; }
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Vec2 &operator+=(const Vec2 &v) {
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x += v.x;
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y += v.y;
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return *this;
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}
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Vec2 &operator-=(const Vec2 &v) {
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x -= v.x;
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y -= v.y;
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return *this;
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}
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Vec2 &operator*=(float s) {
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x *= s;
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y *= s;
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return *this;
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}
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Vec2 &operator/=(float s) {
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x /= s;
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y /= s;
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return *this;
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}
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bool operator==(const Vec2 &v) const { return x == v.x && y == v.y; }
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bool operator!=(const Vec2 &v) const { return !(*this == v); }
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// 向量运算
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float length() const { return std::sqrt(x * x + y * y); }
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float lengthSquared() const { return x * x + y * y; }
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Vec2 normalized() const {
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float len = length();
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if (len > 0.0f)
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return {x / len, y / len};
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return {0.0f, 0.0f};
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}
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float dot(const Vec2 &v) const { return x * v.x + y * v.y; }
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float cross(const Vec2 &v) const { return x * v.y - y * v.x; }
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float distance(const Vec2 &v) const { return (*this - v).length(); }
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float angle() const { return std::atan2(y, x) * RAD_TO_DEG; }
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static Vec2 lerp(const Vec2 &a, const Vec2 &b, float t) {
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return a + (b - a) * t;
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}
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static constexpr Vec2 Zero() { return {0.0f, 0.0f}; }
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static constexpr Vec2 One() { return {1.0f, 1.0f}; }
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static constexpr Vec2 UnitX() { return {1.0f, 0.0f}; }
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static constexpr Vec2 UnitY() { return {0.0f, 1.0f}; }
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};
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inline Vec2 operator*(float s, const Vec2 &v) { return v * s; }
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using Point = Vec2;
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} // namespace extra2d
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