167 lines
3.7 KiB
C++
167 lines
3.7 KiB
C++
// * This file is part of the COLOBOT source code
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// * Copyright (C) 2012, Polish Portal of Colobot (PPC)
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// *
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// * This program is free software: you can redistribute it and/or modify
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// * it under the terms of the GNU General Public License as published by
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// * the Free Software Foundation, either version 3 of the License, or
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// * (at your option) any later version.
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// *
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// * This program is distributed in the hope that it will be useful,
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// * but WITHOUT ANY WARRANTY; without even the implied warranty of
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// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// * GNU General Public License for more details.
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// *
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// * You should have received a copy of the GNU General Public License
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// * along with this program. If not, see http://www.gnu.org/licenses/.
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/** @defgroup MathPointModule math/point.h
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Contains the Point struct and related functions.
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*/
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#pragma once
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#include "const.h"
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#include "func.h"
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#include <cmath>
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/* TODO
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FPOINT RotatePoint(FPOINT center, float angle, FPOINT p);
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FPOINT RotatePoint(float angle, FPOINT p);
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FPOINT RotatePoint(float angle, float dist);
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void RotatePoint(float cx, float cy, float angle, float &px, float &py);
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float RotateAngle(FPOINT center, FPOINT p1, FPOINT p2);
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*/
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// Math module namespace
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namespace Math
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{
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/* @{ */ // start of group
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/** \struct Point math/point.h
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\brief 2D point
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Represents a 2D point (x, y).
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Contains the required methods for operating on points.
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All methods are made inline to maximize optimization.
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*/
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struct Point
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{
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//! X coord
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float x;
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//! Y coord
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float y;
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//! Constructs a zero point: (0,0)
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inline Point()
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{
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LoadZero();
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}
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//! Constructs a point from given coords: (x,y)
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inline Point(float x, float y)
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{
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this->x = x;
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this->y = y;
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}
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//! Sets the zero point: (0,0)
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inline void LoadZero()
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{
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x = y = 0.0f;
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}
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//! Returns the distance from (0,0) to the point (x,y)
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inline float Length()
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{
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return std::sqrt(x*x + y*y);
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}
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};
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//! Permutes two points
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inline void Swap(Point &a, Point &b)
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{
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Point c;
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c = a;
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a = b;
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b = c;
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}
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//! Returns the distance between two points
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inline float Distance(const Point &a, const Point &b)
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{
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return sqrt((a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y));
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}
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//! Returns py up on the line \a a - \a b
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inline float MidPoint(const Point &a, const Point &b, float px)
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{
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if (IsEqual(a.x, b.x))
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{
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if (a.y < b.y)
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return HUGE;
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else
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return -HUGE;
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}
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return (b.y-a.y) * (px-a.x) / (b.x-a.x) + a.y;
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}
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//! Calculates the parameters a and b of the linear function passing through \a p1 and \a p2
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/** Returns \c false if the line is vertical.
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\param p1,p2 points
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\param a,b linear function parameters */
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inline bool LinearFunction(const Point &p1, const Point &p2, float &a, float &b)
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{
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if ( IsZero(p1.x-p2.x) )
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{
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a = HUGE;
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b = p2.x;
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return false;
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}
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a = (p2.y-p1.y) / (p2.x-p1.x);
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b = p2.y - p2.x*a;
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return true;
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}
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//! Checks if the point is inside triangle defined by vertices \a a, \a b, \a c
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inline bool IsInsideTriangle(Point a, Point b, Point c, const Point &p)
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{
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if ( p.x < a.x && p.x < b.x && p.x < c.x ) return false;
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if ( p.x > a.x && p.x > b.x && p.x > c.x ) return false;
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if ( p.y < a.y && p.y < b.y && p.y < c.y ) return false;
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if ( p.y > a.y && p.y > b.y && p.y > c.y ) return false;
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if ( a.x > b.x ) Swap(a,b);
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if ( a.x > c.x ) Swap(a,c);
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if ( c.x < a.x ) Swap(c,a);
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if ( c.x < b.x ) Swap(c,b);
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float n, m;
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n = MidPoint(a, b, p.x);
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m = MidPoint(a, c, p.x);
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if ( (n>p.y || p.y>m) && (n<p.y || p.y<m) )
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return false;
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n = MidPoint(c, b, p.x);
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m = MidPoint(c, a, p.x);
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if ( (n>p.y || p.y>m) && (n<p.y || p.y<m) )
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return false;
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return true;
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}
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/* @} */ // end of group
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}; // namespace Math
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