void add_grain_on_random_square (int radius, int seed)
{
TRACEINW("(radius=%d seed=%d)", radius, seed);
srandom(seed);
int random_x = random_number_in_range(-radius, radius);
int random_y = random_number_in_range(-radius, radius);
TRACEMESS("Add 1 grain on (%d,%d)", random_x, random_y);
add_grains_on_square(random_x, random_y, 1);
TRACEOUT;
}
/* ADD_GRAINS_ON_SQUARE modifies the board by adding DELTA (can be 0) on X,Y.
Maintains counts. No collapse.
New val ≥ 4 are stacked in waiting list (no checking if new val ≠ prev val)
Prev val ≥ 4 are assumed to have been unstacked by caller */
void add_grains_on_square (int x, int y, int delta)
{
TRACEINW("(x=%d, y=%d, delta=%d)", x, y, delta);
// dump_waitinglist(stdout, true);
if ((x < xmin) || (x > xmax) || (y < ymin) || (y > ymax)) {
TRACEMESS ("have to enlarge");
enlarge_envelop_for (x,y);
}
int * p = cboard + x*ydim + y;
int val = *p;
assert ((val + delta >= 0) || (val == UNUSEDSQ));
switch (val) {//update count
case 0: assert(count0 > 0); count0--; break;
case 1: assert(count1 > 0); count1--; break;
case 2: assert(count2 > 0); count2--; break;
case 3: assert(count3 > 0); count3--; break;
case UNUSEDSQ: val=0; area++; break; /* needs real val in later computation */
default: assert(val>3); /* do nothing */
}
mass += delta;
val += delta;
*p = val;
switch (val) {
case 0: assert(count0 < INT_MAX); count0++; break;
case 1: assert(count1 < INT_MAX); count1++; break;
case 2: assert(count2 < INT_MAX); count2++; break;
case 3: assert(count3 < INT_MAX); count3++; break;
default:
assert(val>3);
/* only stackin when val goes 3->4, 7->8, ... Other options are 5->6, 8->4 etc. */
if ((val%4 == 0) && (delta == 1)) stackin_waiting(x,y);
break;
}
#ifdef TRACE
if ((terminal_mode != false) && (anim_level >= 2))
dump_waitinglist(stdout, false);
#endif /* TRACE */
TRACEOUT;
}
