/* fixatan2:
* Like the libc atan2, but for fixed point numbers.
*/
fixed fixatan2(fixed y, fixed x)
{
fixed r;
if (x==0) {
if (y==0) {
*allegro_errno = EDOM;
return 0L;
}
else
return ((y < 0) ? -0x00400000L : 0x00400000L);
}
*allegro_errno = 0;
r = fixdiv(y, x);
if (*allegro_errno) {
*allegro_errno = 0;
return ((y < 0) ? -0x00400000L : 0x00400000L);
}
r = fixatan(r);
if (x >= 0)
return r;
if (y >= 0)
return 0x00800000L + r;
return r - 0x00800000L;
}
void evaluatePhysics()
{
if (theShip.x > MAPWIDTH)
{
theShip.x = MAPWIDTH;
theShip.velX *= -1;
}
if (theShip.x < 0)
{
theShip.x = 0;
theShip.velX *= -1;
}
if (theShip.y > 768)
{
theShip.y = 768;
theShip.velY *= -1;
}
if (theShip.y < 0)
{
theShip.y = 0;
theShip.velY *= -1;
}
theShip.rotation += theShip.velRotation;
theShip.velX += fixtof(fixsin(ftofix(theShip.rotation))) * (theShip.rocketPower/theShip.mass) * 0.99;
theShip.velY -= fixtof(fixcos(ftofix(theShip.rotation))) * (theShip.rocketPower/theShip.mass) * 0.99;
theShip.x += theShip.velX;
theShip.y += theShip.velY;
OBJECT *theRock = rockHeader;
static float distance;
static float diffX;
static float diffY;
static float fG;
static float fGX;
static float fGY;
static float rockX;
static float rockY;
static float shipX;
static float shipY;
shipX = theShip.x + (theShip.width / 2);
shipY = theShip.y + (theShip.height / 2);
while (theRock != NULL)
{
rockX = theRock->x + (theRock->width) / 2;
rockY = theRock->y + (theRock->height) / 2;
diffX = (shipX - rockX);
diffY = (shipY - rockY);
distance = (pow(pow(diffX, 2)+ pow(diffY, 2), 0.5));
fG = 25 * theShip.mass * theRock->mass / pow(distance, 2);
fGX = fixtof(fixcos(fixatan(ftofix(diffY/diffX)))) * fG / theShip.mass;
fGY = fixtof(fixsin(fixatan(ftofix(diffY/diffX)))) * fG / theShip.mass;
theShip.velX += ((shipX > rockX) ? -fGX : fGX);
theShip.velY += ((shipX > rockX) ? -fGY : fGY);
putpixel(screenBuffer, (int)shipX, (int)shipY, makecol(255, 255, 255));
if (shipX > theRock->x && shipX < theRock->x + theRock->width)
{
if (shipY > theRock->y && shipY < theRock->y + theRock->height)
{
theShip.x = 462;
theShip.y = 359;
theShip.rotation = 0;
theShip.velRotation = 0;
theShip.velX = 0;
theShip.velY = 0;
theShip.fuel = theShip.maxFuel;
if (currentTime > highTime)
{
highTime = currentTime;
}
currentTime = 0;
}
}
theRock = theRock->next;
}
}
