int tir_parabolic(int x_inici, int y_inici, double angle, double forca, int x_actual, int vent){
	double v_x,v_y; // Velocitats inicials
	double t; // Temps transcorregut
	
	v_x = cos((double)angle)*(double)forca;
	v_y = sin((double)angle)*(double)forca;
	//t = ((float)x_actual-(float)x_inici)/v_x;
	t = (-v_x - sqrt(v_x*v_x-(double)(2*vent*(x_inici-x_actual))))/(double)vent;
	
	if (t < 0) 
		t = (-v_x + sqrt(v_x*v_x-(double)(2*vent*(x_inici-x_actual))))/(double)vent;
	
	printf("%d\n",(int)t);
	
	if (v_x==0) {
		return -1;
	}
	else {
		return (int)(y_inici+(int)v_y*t-(int)(GRAVETAT/2.0)*(t*t));
	}
}

void efectua_dispar(int x_inici, int y_inici, double angle, double forca, int* terreny, int ample, int alt, int vent, CTancs *tancs){
	int i, j, tmp, t=0;
	int x, y;
	int taurell[ample][alt];
	int radi = DISPAR_RADI;
	int contador;
	
	while (angle > PI) {
		angle -= PI;
	}

	while (angle < 0) {
		angle += PI;
	}
	if (angle < PI/2.0) {
		
		for (i = x_inici; i < ample && j!=-1; i++ ) {
			j = tir_parabolic(x_inici, terreny[x_inici]+10, angle, forca, i, vent);
			if(j>=terreny[i] && j < alt){
				dibuixa_pixel(i,j,COLOR_BLANC);
	
			//TODO : Podriem dibuixar línees en lloc de punts, les
			//       bales segueixen una trajectòria contínua :-)

			} else if (j < terreny[i]){
				j =- 1;
			}
			tmp = i+1;
		}
		y=terreny[tmp-1];
	}
	else {
		for (i=x_inici; i >= 0 && j!=-1; i--) {
			j=tir_parabolic(x_inici, terreny[x_inici]+10, angle, forca, i, vent);

			if(j>=terreny[i] && j<alt){
				dibuixa_pixel(i,j,COLOR_BLANC);
			}
			else if (j < terreny[i]) {
				j =- 1;
			}
			tmp = i-1;
		}
		y=terreny[tmp+1];
	}