void ioDestroy(void) {
if (eventThreadID != -1) {
threadkill(eventThreadID);
}
closemouse(mousectl);
closekeyboard(keyboardctl);
}
int main(void)
{
int count = 0;
int G_pressed = 0, R_pressed = 1;
char vstring[10], wstring[10];
double x1_old, y1_old;
double x2_old, y2_old;
double x1_new, y1_new;
double x2_new, y2_new;
double vx, vy, wx, wy;
double v, w;
posvel pv;
x1_old = 100.0;
y1_old = 100.0;
vx = 10.0;
vy = 5.0;
x2_old = 250.0;
y2_old = 250.0;
wx = -8.0;
wy = 4.0;
v = sqrt(pow(wx,2)+pow(wy,2));
w = sqrt(pow(vx,2)+pow(vy,2));
/* open the graphics window */
initwindow(XWINDOW, YWINDOW);
/* allow mouse operations */
initmouse();
/* allow keyboard operations */
initkeyboard();
/* create an event queue */
create_event_queue();
/* register display, mouse and keyboard as event sources */
reg_display_events();
reg_mouse_events();
reg_keyboard_events();
/* initialize the font */
initfont();
outtextxy(4,5,"To quit press left mouse button or close graphics window");
outtextxy(4,15,"To pause press right mouse button");
outtextxy(4,25,"To change ball speed use arrow keys (up/down = red, left/right = blue)");
outtextxy(4,35,"To make the red ball green press G or g ");
do
{
if (check_if_event())
{
/* wait for event */
wait_for_event();
if (event_close_display())
break;
else if (event_mouse_button_down())
{
if (event_mouse_left_button_down())
break;
else if (event_mouse_right_button_down())
wait_for_event();
}
else if (event_key_down())
{ /* change speed of first ball */
if(event_key_up_arrow())
{
vx = 1.25*vx;
vy = 1.25*vy;
}
else if(event_key_down_arrow())
{
vx = 0.75*vx;
vy = 0.75*vy;
}
else if(event_key_left_arrow())
{
wx = 0.75*wx;
wy = 0.75*wy;
}
else if(event_key_right_arrow())
{
wx = 1.25*wx;
wy = 1.25*wy;
}
if (event_key('G'))
{
G_pressed = 1;
R_pressed = 0;
}
else if (event_key('R'))
{
R_pressed = 1;
G_pressed = 0;
}
}
}
v = sqrt(pow(wx,2)+pow(wy,2));
w = sqrt(pow(vx,2)+pow(vy,2));
/* calculate new ball positions */
x1_new = x1_old + vx*TICK;
y1_new = y1_old + vy*TICK;
x2_new = x2_old + wx*TICK;
y2_new = y2_old + wy*TICK;
/* handle what to do if balls hit boundaries */
pv = hit_boundary(x1_new, vx, 1);
x1_new = pv.pos;
vx = pv.vel;
pv = hit_boundary(x2_new, wx, 1);
x2_new = pv.pos;
wx = pv.vel;
pv = hit_boundary(y1_new, vy, 0);
y1_new = pv.pos;
vy = pv.vel;
pv = hit_boundary(y2_new, wy, 0);
y2_new = pv.pos;
wy = pv.vel;
/* draw balls on screen buffer in new positions */
filled_circle(x1_new, y1_new, RADIUS , BLUE);
if (G_pressed)
filled_circle(x2_new, y2_new, RADIUS , GREEN);
else if (R_pressed)
filled_circle(x2_new, y2_new, RADIUS , RED);
/* make the balls visible on the screen display
and remove the balls in the previous positions */
sprintf(vstring, "%4.2lf", v);
sprintf(wstring, "%4.2lf", w);
setcolor(RED);
outtextxy(VEL_TEXT_X,VEL_TEXT_Y,"v = ");
/* clear area for numeric output */
filled_rectangle(VEL_TEXT_X+40, VEL_TEXT_Y-10, VEL_TEXT_X+100, VEL_TEXT_Y+20, BLACK);
outtextxy(VEL_TEXT_X+60,VEL_TEXT_Y,vstring);
setcolor(BLUE);
outtextxy(VEL_TEXT_X+120,VEL_TEXT_Y,"w = ");
/* clear area for numeric output */
filled_rectangle(VEL_TEXT_X+160, VEL_TEXT_Y-10, VEL_TEXT_X+220, VEL_TEXT_Y+20, BLACK);
outtextxy(VEL_TEXT_X+180,VEL_TEXT_Y,wstring);
update_display();
/* remove the balls in the previous positions on
the screen buffer */
filled_circle(x1_old, y1_old, RADIUS , BLACK);
filled_circle(x2_old, y2_old, RADIUS , BLACK);
/* update the old positions */
x1_old = x1_new;
y1_old = y1_new;
x2_old = x2_new;
y2_old = y2_new;
count++;
pausefor(8); /* wait 8 miliseconds */
}
while (count < MAXCOUNT);
/* close the mouse */
closemouse();
/* remove the display */
closegraph();
return 0;
}
