// Header File
// Created 10/12/2003; 16:30:49
//Algorithmes de collisions

//Test de collision (type collision avec billes)
short Test_Collide_0 (short x0, short y0, short x1, short y1, unsigned char w0, unsigned char h0, unsigned char w1, unsigned char h1)
{
	short distx=abs ((x0+w0/2)-(x1+w1/2));
	short disty=abs ((y0+h0/2)-(y1+h1/2));
	
	if ((distx<(w0/2+w1/2)) && (disty<(h0/2+h1/2))) 
	{
		distx=((w0/2)+(w1/2))-distx;
		disty=((h0/2)+(h1/2))-disty;
		
		if (distx>disty) 
		{
			return disty;
			
			//if (disty>0) return disty++;
			//else return disty--;
		}
		else 
		{
			return distx;
			
			//if (distx>0) return distx++;
			//return distx--;
		}
	}
	
	return 0;
}

/*unsigned char GetDirCollide_0 (short x0, short y0, short x1, short y1, unsigned char w0, unsigned char h0, unsigned char w1, unsigned char h1)
{
	short distx=abs ((x0+w0/2)-(x1+w1/2));
	short disty=abs ((y0+h0/2)-(y1+h1/2));
	
	if ((distx<(w0/2+w1/2)) && (disty<(h0/2+h1/2))) 
	{
		distx=((w0/2)+(w1/2))-distx;
		disty=((h0/2)+(h1/2))-disty;
		
		if (distx>disty) return 2; //y
		else return 1; //x
	}
	
	return 0;
}*/


//Collision entre rectangles.
short TestCollideSquare (short x0, short y0, short x1, short y1, unsigned char w0, unsigned char h0, unsigned char w1, unsigned char h1)
{
	short distx0,distx1;
	short disty0,disty1;
	
	//Si pas collision
	if (((y1+h1)<y0) || (y1>(y0+h0)) ||
			((x1+w1)<x0) || (x1>(x0+w0)))
		return 0;
	
	//Détermine la plus petite distance à parcourir pour éviter collision
	disty0=(y1+h1)-y0+1;
	disty1=(y0+h0)-y1+1;
	
	distx0=(x1+w1)-x0+1;
	distx1=(x0+w0)-x1+1;
	
	if (distx1<distx0) distx0=distx1;
	if (disty1<disty0) disty0=disty1;
	
	if (distx0>disty0) distx0=disty0;
	
	if (distx0) return distx0;
	else return 1;
}

//Direction de la collision
unsigned char GetDirCollideSquare (short x0, short y0, short x1, short y1, unsigned char w0, unsigned char h0, unsigned char w1, unsigned char h1)
{
	//Si pas collision
	if (((y1+h1)<y0) || (y1>(y0+h0)))
		return 2; //y
	
	if (((x1+w1)<x0) || (x1>(x0+w0)))
		return 1; //x
		
	return 0;
}

//Direction de la collision
unsigned char GetDirCollideSquare2 (short x0, short y0, short x1, short y1, unsigned char w0, unsigned char h0, unsigned char w1, unsigned char h1)
{
	unsigned char collide=0;
	
	//Si pas collision
	if ((y1+h1)<y0+(h0/2))
		collide|=1; //y		Haut
		
	if (y1>(y0+(h0/2)))
		collide|=2;	//y		Bas
	
	if ((x1+w1)<x0+(w0/2))
		collide|=4; //x		Gauche
	
	if (x1>(x0+(w0/2)))
		collide|=8;	//x		Droit
		
	return collide;
}

/*#define SWAPDATA(a,b) asm volatile ("exg %0,%1" : "=d" (a), "=d" (b) : "0" (a), "1" (b) : "cc")
//Teste collision entre sprite de 8 pixels
BOOL TestCollideSprite8 (short x0, short y0, short x1, short y1, unsigned char h, unsigned char *sprite0, unsigned char *sprite1)
{
	short dx,dy,i;
		
	//Sprite 0 à droite de sprite 1
	if (x0<x1) dx=x1-x0;
	else
	{
		//Si sprite0 est à droite de sprite 1 juste
		//echanger les variables
		dx=x0-x1;
		SWAPDATA (sprite0,sprite1);
		SWAPDATA (y0,y1);
	}
	
	if (dx>=8) return 0; //Aucune collision
	
	if (y0<y1)
	{
		dy=y1-y0;
		sprite0+=dy;
	}
	else
	{
		dy=y0-y1;
		sprite1+=dy;
	}
	
	for (i=dy;i<h;i++,sprite0++,sprite1++)
	{
		if (((unsigned short)*sprite1) & (((unsigned short)*sprite0)<<dx))
			return 1;
	}
	
	return 0;
}

//Teste collision entre sprite de 16 pixels
BOOL TestCollideSprite16 (short x0, short y0, short x1, short y1, unsigned char h, unsigned short *sprite0, unsigned short *sprite1)
{
	short dx,dy,i;
		
	//Sprite 0 à droite de sprite 1
	if (x0<x1) dx=x1-x0;
	else
	{
		//Si sprite0 est à droite de sprite 1 juste
		//echanger les variables
		dx=x0-x1;
		SWAPDATA (sprite0,sprite1);
		SWAPDATA (y0,y1);
	}
	
	if (dx>=16) return 0; //Aucune collision
	
	if (y0<y1)
	{
		dy=y1-y0;
		sprite0+=dy;
	}
	else
	{
		dy=y0-y1;
		sprite1+=dy;
	}
	
	for (i=dy;i<h;i++,sprite0++,sprite1++)
	{
		if (((unsigned long)*sprite1) & (((unsigned long)*sprite0)<<dx))
			return 1;
	}
	
	return 0;
}

//Teste collision entre sprite de 32 pixels
short TestCollideSprite32 (short x0, short y0, short x1, short y1, unsigned char h, unsigned long *sprite0, unsigned long *sprite1)
{
	short dx,dy,i;
		
	//Sprite 0 à droite de sprite 1
	if (x0<x1) dx=x1-x0;
	else
	{
		//Si sprite0 est à droite de sprite 1 juste
		//echanger les variables
		dx=x0-x1;
		SWAPDATA (sprite0,sprite1);
		SWAPDATA (y0,y1);
	}
	
	if (dx>=32) return 0; //Aucune collision
	
	if (y0<y1)
	{
		dy=y1-y0;
		sprite0+=dy;
	}
	else
	{
		dy=y0-y1;
		sprite1+=dy;
	}
		
	for (i=dy;i<h;i++,sprite0++,sprite1++)
	{
		if ((((unsigned long)*sprite1)>>dx) & (((unsigned long)*sprite0)))
			return 1;
	}
	
	return 0;
}*/