godot-cpp/src/core/Rect2.cpp

#include "Rect2.hpp"
#include "Vector2.hpp"
#include "String.hpp"
#include "Transform2D.hpp"

#include <cmath>

namespace godot {

#ifndef MAX
#define MAX(a, b) (a > b ? a : b)
#endif

#ifndef MIN
#define MIN(a, b) (a < b ? a : b)
#endif


real_t Rect2::distance_to(const Vector2& p_point) const {

		real_t dist = 1e20;

		if (p_point.x < pos.x) {
			dist=MIN(dist,pos.x-p_point.x);
		}
		if (p_point.y < pos.y) {
			dist=MIN(dist,pos.y-p_point.y);
		}
		if (p_point.x >= (pos.x+size.x) ) {
			dist=MIN(p_point.x-(pos.x+size.x),dist);
		}
		if (p_point.y >= (pos.y+size.y) ) {
			dist=MIN(p_point.y-(pos.y+size.y),dist);
		}

		if (dist==1e20)
			return 0;
		else
			return dist;
	}

Rect2 Rect2::clip(const Rect2& p_rect) const { /// return a clipped rect

	Rect2 new_rect=p_rect;

	if (!intersects( new_rect ))
		return Rect2();

	new_rect.pos.x = MAX( p_rect.pos.x , pos.x );
	new_rect.pos.y = MAX( p_rect.pos.y , pos.y );

	Point2 p_rect_end=p_rect.pos+p_rect.size;
	Point2 end=pos+size;

	new_rect.size.x=MIN(p_rect_end.x,end.x) - new_rect.pos.x;
	new_rect.size.y=MIN(p_rect_end.y,end.y) - new_rect.pos.y;

	return new_rect;
}

Rect2 Rect2::merge(const Rect2& p_rect) const { ///< return a merged rect

	Rect2 new_rect;

	new_rect.pos.x=MIN( p_rect.pos.x , pos.x );
	new_rect.pos.y=MIN( p_rect.pos.y , pos.y );


	new_rect.size.x = MAX( p_rect.pos.x+p_rect.size.x , pos.x+size.x );
	new_rect.size.y = MAX( p_rect.pos.y+p_rect.size.y , pos.y+size.y );

	new_rect.size = new_rect.size - new_rect.pos; //make relative again

	return new_rect;
}



Rect2::operator String() const
{
	return String(pos)+", "+String(size);
}


bool Rect2::intersects_segment(const Point2& p_from, const Point2& p_to, Point2* r_pos,Point2* r_normal) const {

	real_t min=0,max=1;
	int axis=0;
	real_t sign=0;

	for(int i=0;i<2;i++) {
		real_t seg_from=p_from[i];
		real_t seg_to=p_to[i];
		real_t box_begin=pos[i];
		real_t box_end=box_begin+size[i];
		real_t cmin,cmax;
		real_t csign;

		if (seg_from < seg_to) {

			if (seg_from > box_end || seg_to < box_begin)
				return false;
			real_t length=seg_to-seg_from;
			cmin = (seg_from < box_begin)?((box_begin - seg_from)/length):0;
			cmax = (seg_to > box_end)?((box_end - seg_from)/length):1;
			csign=-1.0;

		} else {

			if (seg_to > box_end || seg_from < box_begin)
				return false;
			real_t length=seg_to-seg_from;
			cmin = (seg_from > box_end)?(box_end - seg_from)/length:0;
			cmax = (seg_to < box_begin)?(box_begin - seg_from)/length:1;
			csign=1.0;
		}

		if (cmin > min) {
			min = cmin;
			axis=i;
			sign=csign;
		}
		if (cmax < max)
			max = cmax;
		if (max < min)
			return false;
	}


	Vector2 rel=p_to-p_from;

	if (r_normal) {
		Vector2 normal;
		normal[axis]=sign;
		*r_normal=normal;
	}

	if (r_pos)
		*r_pos=p_from+rel*min;

	return true;
}


bool Rect2::intersects_transformed(const Transform2D& p_xform, const Rect2& p_rect) const {

	//SAT intersection between local and transformed rect2

	Vector2 xf_points[4]={
		p_xform.xform(p_rect.pos),
		p_xform.xform(Vector2(p_rect.pos.x+p_rect.size.x,p_rect.pos.y)),
		p_xform.xform(Vector2(p_rect.pos.x,p_rect.pos.y+p_rect.size.y)),
		p_xform.xform(Vector2(p_rect.pos.x+p_rect.size.x,p_rect.pos.y+p_rect.size.y)),
	};

	real_t low_limit;

	//base rect2 first (faster)

	if (xf_points[0].y>pos.y)
		goto next1;
	if (xf_points[1].y>pos.y)
		goto next1;
	if (xf_points[2].y>pos.y)
		goto next1;
	if (xf_points[3].y>pos.y)
		goto next1;

	return false;

	next1:

	low_limit=pos.y+size.y;

	if (xf_points[0].y<low_limit)
		goto next2;
	if (xf_points[1].y<low_limit)
		goto next2;
	if (xf_points[2].y<low_limit)
		goto next2;
	if (xf_points[3].y<low_limit)
		goto next2;

	return false;

	next2:

	if (xf_points[0].x>pos.x)
		goto next3;
	if (xf_points[1].x>pos.x)
		goto next3;
	if (xf_points[2].x>pos.x)
		goto next3;
	if (xf_points[3].x>pos.x)
		goto next3;

	return false;

	next3:

	low_limit=pos.x+size.x;

	if (xf_points[0].x<low_limit)
		goto next4;
	if (xf_points[1].x<low_limit)
		goto next4;
	if (xf_points[2].x<low_limit)
		goto next4;
	if (xf_points[3].x<low_limit)
		goto next4;

	return false;

	next4:

	Vector2 xf_points2[4]={
		pos,
		Vector2(pos.x+size.x,pos.y),
		Vector2(pos.x,pos.y+size.y),
		Vector2(pos.x+size.x,pos.y+size.y),
	};

	real_t maxa=p_xform.elements[0].dot(xf_points2[0]);
	real_t mina=maxa;

	real_t dp = p_xform.elements[0].dot(xf_points2[1]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[0].dot(xf_points2[2]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[0].dot(xf_points2[3]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	real_t maxb=p_xform.elements[0].dot(xf_points[0]);
	real_t minb=maxb;

	dp = p_xform.elements[0].dot(xf_points[1]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[0].dot(xf_points[2]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[0].dot(xf_points[3]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);


	if ( mina > maxb )
		return false;
	if ( minb > maxa  )
		return false;

	maxa=p_xform.elements[1].dot(xf_points2[0]);
	mina=maxa;

	dp = p_xform.elements[1].dot(xf_points2[1]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[1].dot(xf_points2[2]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[1].dot(xf_points2[3]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	maxb=p_xform.elements[1].dot(xf_points[0]);
	minb=maxb;

	dp = p_xform.elements[1].dot(xf_points[1]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[1].dot(xf_points[2]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[1].dot(xf_points[3]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);


	if ( mina > maxb )
		return false;
	if ( minb > maxa  )
		return false;


	return true;

}

}