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];
+
+int32_t rcnt, lrcnt;
+int32_t rsum, rsamples;
+float ravg;
+
+uint32_t nrocks;
+uint32_t nrocks_timer;
+uint32_t nrocks_inc_ticks = 2*60*1000/(F_ROCKS-I_ROCKS);
+
+// 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));
}
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;
+ int i;
+
+ for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
+ nrocks = I_ROCKS;
+ nrocks_timer = 0;
+ rcnt = 0; lrcnt = -1;
+ rsum = 0; rsamples = 0;
+}
+
+enum { LEFT, RIGHT, TOP, BOTTOM };
+
+
+// compute the number of rocks/seccond that should be coming from each side
+
+// compute the speed ranges of rocks coming from each side
+void
+rock_sides(float *ti, float *speed_min, float *speed_max)
+{
+ float dx0,dx1, dy0,dy1;
+ float hfactor, vfactor;
+ int i;
+
+ for(i=0; i<4; i++) ti[i] = 0;
+ for(i=0; i<4; i++) speed_min[i] = 0;
+ for(i=0; i<4; i++) speed_max[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) {
+ speed_max[RIGHT] = -dx0;
+ if(dx1 < 0) {
+ // Rocks moving left only. So the RIGHT side of the screen
+ speed_min[RIGHT] = -dx1;
+ ti[RIGHT] = -(dx0+dx1)/2;
+ } else {
+ // Rocks moving left and right
+ speed_max[LEFT] = dx1;
+ ti[RIGHT] = -dx0/2;
+ ti[LEFT] = dx1/2;
+ }
+ } else {
+ // Rocks moving right only. So the LEFT side of the screen
+ speed_min[LEFT] = dx0;
+ speed_max[LEFT] = dx1;
+ ti[LEFT] = (dx0+dx1)/2;
}
- if(gamerate>0.1) {
- countdown = (int)(ROCKRATE/gamerate);
+ }
+ ti[LEFT] *= hfactor;
+ ti[RIGHT] *= hfactor;
+
+ if(dy0 != 0) {
+ if(dy0 < 0) {
+ speed_max[BOTTOM] = -dy0;
+ if(dy1 < 0) {
+ // Rocks moving up only. So the BOTTOM of the screen
+ speed_min[BOTTOM] = -dy1;
+ ti[BOTTOM] = -(dy0+dy1)/2;
+ } else {
+ // Rocks moving up and down
+ speed_max[TOP] = dy1;
+ ti[BOTTOM] = -dy0/2;
+ ti[TOP] = dy1/2;
+ }
} else {
- countdown = 0;
+ // Rocks moving down only. so the TOP of the screen
+ speed_min[TOP] = dy0;
+ speed_max[TOP] = dy1;
+ ti[TOP] = (dy0+dy1)/2;
}
}
+ ti[TOP] *= vfactor;
+ ti[BOTTOM] *= vfactor;
+}
+
+float
+weighted_rnd_range(float min, float max) {
+ return sqrt(min * min + rnd() * (max * max - min * min));
}
void
-move_rocks(void)
+new_rocks(void)
{
- int i;
+ int i,j;
+ float ti[4];
+ float rmin[4];
+ float rmax[4];
- // 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;
- }
+ if(nrocks < F_ROCKS) {
+ nrocks_timer += ticks_since_last;
+ if(nrocks_timer >= nrocks_inc_ticks) {
+ nrocks_timer -= nrocks_inc_ticks;
+ nrocks++;
+ }
+ }
+
+ rock_sides(ti, rmin, rmax);
+
+ // loop through the four sides of the screen
+ for(i=0; i<4; i++) {
+ // see if we generate a rock for this side this frame
+ rtimers[i] += ti[i]*gamerate/20;
+ while(rtimers[i] >= 1) {
+ rtimers[i] -= 1;
+ j=0;
+ while(rockptr->active && j<MAXROCKS) {
+ if(++rockptr - rock >= MAXROCKS) rockptr = rock;
+ j++;
}
- 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;
+ if(!rockptr->active) {
+ 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);
+
+ rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
+ rockptr->dy = RDY*crnd();
+ break;
+ case LEFT:
+ rockptr->x = -rockptr->image->w;
+ rockptr->y = rnd()*(YSIZE + rockptr->image->h);
+
+ rockptr->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
+ rockptr->dy = RDY*crnd();
+ break;
+ case BOTTOM:
+ rockptr->x = rnd()*(XSIZE + rockptr->image->w);
+ rockptr->y = YSIZE;
+
+ rockptr->dx = RDX*crnd();
+ rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
+ break;
+ case TOP:
+ rockptr->x = rnd()*(XSIZE + rockptr->image->w);
+ rockptr->y = -rockptr->image->h;
+
+ rockptr->dx = RDX*crnd();
+ rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
+ break;
+ }
+
+ rockptr->active = 1;
+ rcnt++;
}
}
}
}
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;
+ rcnt--;
+ }
+ }
}
-
- rockrate = 54.0;
- rockspeed = 5.0;
+ /*
+ if(lrcnt == -1 && rcnt == nrocks) lrcnt = 0;
+ if(rcnt != lrcnt && lrcnt != -1) {
+ lrcnt = rcnt;
+ rsum += rcnt-nrocks; rsamples++;
+ ravg = (float) rsum / rsamples;
+ printf("%.2f%%\n", 100.0 * ravg / nrocks);
+ }
+ */
}
void
int i;
float dx, dy, n;
+ if(onlyslow) return;
+
for(i = 0; i<MAXROCKS; i++ ) {
if(rock[i].x <= 0) continue;
// 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;
+ n *= 15;
+ rock[i].dx += 54.0*dx/n;
+ rock[i].dy += 54.0*dy/n;
}
}
}
Got questions, comments, patches, etc.? Contact Jason Woofenden