Simulation of the Gravity Beats app
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//
// Math.h
// GravityBeats
//
// Created by Joshua Moerman on 1/12/13.
// Copyright (c) 2013 Vadovas. All rights reserved.
//
#ifndef GravityBeats_Math_h
#define GravityBeats_Math_h
#include <cmath>
namespace math {
struct Vec2 {
float x, y;
Vec2& operator *= (float rh){
x *= rh;
y *= rh;
return *this;
}
Vec2& operator+= (Vec2 const & rh){
x += rh.x;
y += rh.y;
return *this;
}
float sqr_length() const {
return x*x + y*y;
}
float length() const {
return std::sqrt(sqr_length());
}
Vec2& normalize(){
const float l = length();
if(l == 0.0f) { return *this; }
x /= l;
y /= l;
return *this;
}
};
inline Vec2 operator*(float lh, Vec2 rh){
rh *= lh;
return rh;
}
inline Vec2 operator+(Vec2 lh, Vec2 const & rh){
return lh += rh;
}
inline Vec2 operator-(Vec2 lh, Vec2 const & rh){
return lh += -1.0*rh;
}
inline float dot(Vec2 const & lh, Vec2 const & rh){
return lh.x*rh.x + lh.y*rh.y;
}
inline Vec2 rotate_ccw(Vec2 v){
std::swap(v.x, v.y);
v.x *= -1.0;
return v;
}
inline Vec2 normalize(Vec2 v){
return v.normalize();
}
inline float distance_point_point(Vec2 p1, Vec2 p2){
return (p2 - p1).length();
}
// p point, [v,w] line segment
inline float distance_point_line(Vec2 p, Vec2 v, Vec2 w){
// http://stackoverflow.com/questions/849211/shortest-distance-between-a-point-and-a-line-segment
const float l2 = (v-w).sqr_length();
if (l2 == 0.0) return distance_point_point(p, v);
const float t = dot(p - v, w - v) / l2;
if (t < 0.0) return distance_point_point(p, v);
else if (t > 1.0) return distance_point_point(p, w);
auto projection = v + t * (w - v);
return distance_point_point(p, projection);
}
template <typename T>
constexpr T clamp(T input, T min, T max){
return input > max ? max :
input < min ? min : input;
}
}
#endif