void physics(Game *g)
{
Flt d0,d1,dist;
//Update ship position
g->ship.pos[0] += g->ship.vel[0];
g->ship.pos[1] += g->ship.vel[1];
//Check for collision with window edges
if (g->ship.pos[0] < 0.0) {
g->ship.pos[0] += (float)xres;
}
else if (g->ship.pos[0] > (float)xres) {
g->ship.pos[0] -= (float)xres;
}
else if (g->ship.pos[1] < 0.0) {
g->ship.pos[1] += (float)yres;
}
else if (g->ship.pos[1] > (float)yres) {
g->ship.pos[1] -= (float)yres;
}
//
//
//Update bullet positions
struct timespec bt;
clock_gettime(CLOCK_REALTIME, &bt);
Bullet *b = g->bhead;
while (b) {
//How long has bullet been alive?
double ts = timeDiff(&b->time, &bt);
if (ts > 2.5) {
//time to delete the bullet.
Bullet *saveb = b->next;
deleteBullet(g, b);
b = saveb;
g->nbullets--;
continue;
}
//move the bullet
b->pos[0] += b->vel[0];
b->pos[1] += b->vel[1];
//Check for collision with window edges
if (b->pos[0] < 0.0) {
b->pos[0] += (float)xres;
}
else if (b->pos[0] > (float)xres) {
b->pos[0] -= (float)xres;
}
else if (b->pos[1] < 0.0) {
b->pos[1] += (float)yres;
}
else if (b->pos[1] > (float)yres) {
b->pos[1] -= (float)yres;
}
b = b->next;
}
//
//Update asteroid positions
Asteroid *a = g->ahead;
while (a) {
a->pos[0] += a->vel[0];
a->pos[1] += a->vel[1];
//Check for collision with window edges
if (a->pos[0] < -100.0) {
a->pos[0] += (float)xres+200;
}
else if (a->pos[0] > (float)xres+100) {
a->pos[0] -= (float)xres+200;
}
else if (a->pos[1] < -100.0) {
a->pos[1] += (float)yres+200;
}
else if (a->pos[1] > (float)yres+100) {
a->pos[1] -= (float)yres+200;
}
a->angle += a->rotate;
a = a->next;
}
//
//Asteroid collision with bullets?
//If collision detected:
// 1. delete the bullet
// 2. break the asteroid into pieces
// if asteroid small, delete it
a = g->ahead;
while (a) {
//is there a bullet within its radius?
Bullet *b = g->bhead;
while (b) {
d0 = b->pos[0] - a->pos[0];
d1 = b->pos[1] - a->pos[1];
dist = (d0*d0 + d1*d1);
if (dist < (a->radius*a->radius)) {
//std::cout << "asteroid hit." << std::endl;
//this asteroid is hit.
if (a->radius > 20.0) {
//break it into pieces.
Asteroid *ta = a;
buildAsteroidFragment(ta, a);
int r = rand()%10+5;
for (int k=0; k<r; k++) {
//get the next asteroid position in the array
Asteroid *ta = new Asteroid;
buildAsteroidFragment(ta, a);
//add to front of asteroid linked list
ta->next = g->ahead;
if (g->ahead != NULL)
g->ahead->prev = ta;
g->ahead = ta;
g->nasteroids++;
}
} else {
a->color[0] = 1.0;
a->color[1] = 0.1;
a->color[2] = 0.1;
//asteroid is too small to break up
//delete the asteroid and bullet
Asteroid *savea = a->next;
deleteAsteroid(g, a);
a = savea;
g->nasteroids--;
}
//delete the bullet...
Bullet *saveb = b->next;
deleteBullet(g, b);
b = saveb;
g->nbullets--;
if (a == NULL)
break;
continue;
}
b = b->next;
}
if (a == NULL)
break;
a = a->next;
}
//---------------------------------------------------
//check keys pressed now
if (keys[XK_Left]) {
g->ship.angle += 4.0;
if (g->ship.angle >= 360.0f)
g->ship.angle -= 360.0f;
}
if (keys[XK_Right]) {
g->ship.angle -= 4.0;
if (g->ship.angle < 0.0f)
g->ship.angle += 360.0f;
}
if (keys[XK_Up]) {
//apply thrust
//convert ship angle to radians
Flt rad = ((g->ship.angle+90.0) / 360.0f) * PI * 2.0;
//convert angle to a vector
Flt xdir = cos(rad);
Flt ydir = sin(rad);
g->ship.vel[0] += xdir*0.02f;
g->ship.vel[1] += ydir*0.02f;
Flt speed = sqrt(g->ship.vel[0]*g->ship.vel[0]+
g->ship.vel[1]*g->ship.vel[1]);
if (speed > 10.0f) {
speed = 10.0f;
normalize(g->ship.vel);
g->ship.vel[0] *= speed;
g->ship.vel[1] *= speed;
}
}
if (keys[XK_space]) {
//a little time between each bullet
struct timespec bt;
clock_gettime(CLOCK_REALTIME, &bt);
double ts = timeDiff(&g->bulletTimer, &bt);
if (ts > 0.1) {
timeCopy(&g->bulletTimer, &bt);
//shoot a bullet...
Bullet *b = new Bullet;
timeCopy(&b->time, &bt);
b->pos[0] = g->ship.pos[0];
b->pos[1] = g->ship.pos[1];
b->vel[0] = g->ship.vel[0];
b->vel[1] = g->ship.vel[1];
//convert ship angle to radians
Flt rad = ((g->ship.angle+90.0) / 360.0f) * PI * 2.0;
//convert angle to a vector
Flt xdir = cos(rad);
Flt ydir = sin(rad);
b->pos[0] += xdir*20.0f;
b->pos[1] += ydir*20.0f;
b->vel[0] += xdir*6.0f + rnd()*0.1;
b->vel[1] += ydir*6.0f + rnd()*0.1;
b->color[0] = 1.0f;
b->color[1] = 1.0f;
b->color[2] = 1.0f;
//add to front of bullet linked list
b->next = g->bhead;
if (g->bhead != NULL)
g->bhead->prev = b;
g->bhead = b;
g->nbullets++;
}
}
}
void physics(Game *g)
{
Flt d0,d1,dist;
//Update ship position
g->ship.pos[0] += g->ship.vel[0];
g->ship.pos[1] += g->ship.vel[1];
//Check for collision with window edges
if (g->ship.pos[0] < 0.0) {
g->ship.pos[0] += (float)xres;
}
else if (g->ship.pos[0] > (float)xres) {
g->ship.pos[0] -= (float)xres;
}
else if (g->ship.pos[1] < 0.0) {
g->ship.pos[1] += (float)yres;
}
else if (g->ship.pos[1] > (float)yres) {
g->ship.pos[1] -= (float)yres;
}
//Update asteroid positions
Asteroid *a = g->ahead;
while (a) {
a->pos[0] += a->vel[0];
a->pos[1] += a->vel[1];
//Check for collision with window edges
if (a->pos[0] < -100.0) {
a->pos[0] += (float)xres+200;
}
else if (a->pos[0] > (float)xres+100) {
a->pos[0] -= (float)xres+200;
}
else if (a->pos[1] < -100.0) {
a->pos[1] += (float)yres+200;
}
else if (a->pos[1] > (float)yres+100) {
a->pos[1] -= (float)yres+200;
}
a->angle += a->rotate;
a = a->next;
}
//
//Asteroid collision with bullets?
//If collision detected:
// 1. delete the bullet
// 2. break the asteroid into pieces
// if asteroid small, delete it
a = g->ahead;
while (a) {
//is there a bullet within its radius?
d0 = g->ship.pos[0] - a->pos[0];
d1 = g->ship.pos[1] - a->pos[1];
d0 = g->ship.pos[0] - a->pos[0];
d1 = g->ship.pos[1] - a->pos[1];
dist = (d0*d0 + d1*d1);
if (dist < (a->radius*a->radius)) {
//std::cout << "asteroid hit." << std::endl;
//this asteroid is hit.
if (a->radius > 20.0) {
//break it into pieces.
Asteroid *ta = a;
buildAsteroidFragment(ta, a);
int r = rand()%10+5;
for (int k=0; k<r; k++) {
//get the next asteroid position in the array
Asteroid *ta = new Asteroid;
buildAsteroidFragment(ta, a);
//add to front of asteroid linked list
ta->next = g->ahead;
if (g->ahead != NULL)
g->ahead->prev = ta;
g->ahead = ta;
g->nasteroids++;
}
} else {
a->color[0] = 1.0;
a->color[1] = 0.1;
a->color[2] = 0.1;
//asteroid is too small to break up
//delete the asteroid and bullet
Asteroid *savea = a->next;
deleteAsteroid(g, a);
a = savea;
g->nasteroids--;
g->ship.radius++;
}
if (a == NULL)
break;
continue;
}
if (a == NULL)
break;
a = a->next;
}
//---------------------------------------------------
//check keys pressed now
if (keys[XK_Left]) {
g->ship.angle += 4.0;
if (g->ship.angle >= 360.0f)
g->ship.angle -= 360.0f;
}
if (keys[XK_Right]) {
g->ship.angle -= 4.0;
if (g->ship.angle < 0.0f)
g->ship.angle += 360.0f;
}
if (keys[XK_Up]) {
//apply thrust
//convert ship angle to radians
Flt rad = ((g->ship.angle+90.0) / 360.0f) * PI * 2.0;
//convert angle to a vector
Flt xdir = cos(rad);
Flt ydir = sin(rad);
g->ship.vel[0] += xdir*0.02f;
g->ship.vel[1] += ydir*0.02f;
Flt speed = sqrt(g->ship.vel[0]*g->ship.vel[0]+
g->ship.vel[1]*g->ship.vel[1]);
if (speed > 10.0f) {
speed = 10.0f;
normalize(g->ship.vel);
g->ship.vel[0] *= speed;
g->ship.vel[1] *= speed;
}
}
}
