struct rock_struct {
float x,y,dx,dy;
int active;
- int dead; // has been blown out of the way
- // to make room for a new ship appearing.
SDL_Surface *image;
struct shape *shape;
int type_number;
struct rock_struct rock[MAXROCKS], *rockptr = rock;
-float rockrate,rockspeed;
-
SDL_Surface *surf_rock[NROCKS];
struct shape rock_shapes[NROCKS];
-int countdown = 0;
+// timers for rock generation.
+float rtimers[4];
+int nrocks;
+
+// constants for rock generation.
+#define KH 32.0 // 32 s for a speed=1 rock to cross the screen horizontally.
+#define KV 24.0 // 24 s for a speed=1 rock to cross the screen vertically.
+#define RDX 2.5 // range for rock dx values (+/-)
+#define RDY 2.5 // range for rock dy values (+/-)
float rnd(void);
-uint32_t area;
+#define crnd() (2*(rnd()-0.5))
+
int
init_rocks(void)
char a[MAX_PATH_LEN];
SDL_Surface *temp;
- area = 0;
-
for(i = 0; i<NROCKS; i++) {
snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
NULLERROR(temp = IMG_Load(a));
NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
get_shape(surf_rock[i], &rock_shapes[i]);
}
+ nrocks = 41;
return 0;
}
void
-new_rocks(void)
+reset_rocks(void)
{
- if(--countdown <= 0 && (rnd()*100.0<(rockrate += 0.025))) {
- // Possibly create a rock
- rockptr++;
- if(rockptr-rock >= MAXROCKS) {
- rockptr = rock;
- }
- if(!rockptr->active) {
- rockptr->dx = -(rockspeed)*(1 + rnd());
- rockptr->dy = rnd()-0.5;
- rockptr->type_number = random() % NROCKS;
- rockptr->image = surf_rock[rockptr->type_number];
- rockptr->shape = &rock_shapes[rockptr->type_number];
- rockptr->x = (float)XSIZE;
- rockptr->y = rnd()*(YSIZE + rockptr->image->h);
- rockptr->active = 1;
- area += rockptr->shape->area;
- }
- if(gamerate>0.1) {
- countdown = (int)(ROCKRATE/gamerate);
- } else {
- countdown = 0;
- }
- }
+ int i;
+
+ for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
}
+enum { LEFT, RIGHT, TOP, BOTTOM };
+
void
-move_rocks(void)
+rock_timer_increments(float *ti)
{
+ float dx0,dx1, dy0,dy1;
+ float hfactor, vfactor;
int i;
- // Move all the rocks
- for(i = 0; i < MAXROCKS; i++) {
- if(rock[i].active) {
- rock[i].x += rock[i].dx*gamerate;
- rock[i].y += rock[i].dy*gamerate + yscroll;
- if(rock[i].y > YSIZE || rock[i].y < -rock[i].image->h) {
- if(rock[i].dead) {
- area -= rock[i].shape->area;
- rock[i].dead = 0;
- rock[i].active = 0;
- } else {
- // wrap
- rock[i].y = (YSIZE - rock[i].image->h) - rock[i].y;
- rock[i].y += (rock[i].dy*gamerate + yscroll) * 1.01;
- }
+ for(i=0; i<4; i++) ti[i] = 0;
+ hfactor = nrocks/KH; vfactor = nrocks/KV;
+
+ dx0 = -RDX - screendx; dx1 = RDX - screendx;
+ dy0 = -RDY - screendy; dy1 = RDY - screendy;
+
+ if(dx0 != 0) {
+ if(dx0 < 0) {
+ if(dx1 < 0) ti[RIGHT] = -(dx0+dx1)/2;
+ else {
+ ti[RIGHT] = -dx0/2;
+ ti[LEFT] = dx1/2;
}
- if(rock[i].x < -rock[i].image->w || rock[i].x > XSIZE) {
- area -= rock[i].shape->area;
- rock[i].active = 0;
- rock[i].dead = 0;
+ } else ti[LEFT] = (dx0+dx1)/2;
+ }
+ ti[LEFT] *= hfactor;
+ ti[RIGHT] *= hfactor;
+
+ if(dy0 != 0) {
+ if(dy0 < 0) {
+ if(dy1 < 0) ti[BOTTOM] = -(dy0+dy1)/2;
+ else {
+ ti[BOTTOM] = -dy0/2;
+ ti[TOP] = dy1/2;
+ }
+ } else ti[TOP] = (dy0+dy1)/2;
+ }
+ ti[TOP] *= vfactor;
+ ti[BOTTOM] *= vfactor;
+}
+
+void
+new_rocks(void)
+{
+ int i,j;
+ float ti[4];
+
+ rock_timer_increments(ti);
+
+ for(i=0; i<4; i++) {
+ rtimers[i] += ti[i]*gamerate/20;
+ if(rtimers[i] >= 1) {
+ j=0;
+ while(rockptr->active && j<MAXROCKS) {
+ if(++rockptr - rock >= MAXROCKS) rockptr = rock;
+ j++;
+ }
+ if(!rockptr->active) {
+ rtimers[i] -= 1;
+ rockptr->type_number = random() % NROCKS;
+ rockptr->image = surf_rock[rockptr->type_number];
+ rockptr->shape = &rock_shapes[rockptr->type_number];
+ switch(i) {
+ case RIGHT:
+ rockptr->x = XSIZE;
+ rockptr->y = rnd()*(YSIZE + rockptr->image->h);
+ break;
+ case LEFT:
+ rockptr->x = -rockptr->image->w;
+ rockptr->y = rnd()*(YSIZE + rockptr->image->h);
+ break;
+ case BOTTOM:
+ rockptr->x = rnd()*(XSIZE + rockptr->image->w);
+ rockptr->y = YSIZE;
+ break;
+ case TOP:
+ rockptr->x = rnd()*(XSIZE + rockptr->image->w);
+ rockptr->y = -rockptr->image->h;
+ break;
+ }
+
+ rockptr->dx = RDX*crnd();
+ rockptr->dy = RDY*crnd();
+
+ rockptr->active = 1;
}
}
}
}
void
-reset_rocks(void)
+move_rocks(void)
{
int i;
- area = 0;
- for(i = 0; i<MAXROCKS; i++ ) {
- rock[i].active = 0;
- rock[i].dead = 0;
+ // Move all the rocks
+ for(i = 0; i < MAXROCKS; i++) {
+ if(rock[i].active) {
+ // move
+ rock[i].x += (rock[i].dx-screendx)*gamerate;
+ rock[i].y += (rock[i].dy-screendy)*gamerate;
+ // clip
+ if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
+ || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
+ rock[i].active = 0;
+ }
+ }
}
-
- rockrate = 54.0;
- rockspeed = 5.0;
}
void
// This makes it so your explosion from dying magically doesn't leave
// any rocks that aren't moving much on the x axis. If onlyslow is set,
// only rocks that are barely moving will be pushed.
- if(onlyslow && (!rock[i].dead || rock[i].dx < -4 || rock[i].dx > 3)) {
- continue;
- }
+ if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
dx = rock[i].x - x;
dy = rock[i].y - y;
n = sqrt(dx*dx + dy*dy);
if(n < radius) {
n *= 20;
- rock[i].dx += rockrate*(dx+30)/n;
- rock[i].dy += rockrate*dy/n;
- rock[i].dead = 1;
+ rock[i].dx += 54.0*dx/n;
+ rock[i].dy += 54.0*dy/n;
}
}
}