rocks.c

   1 #include <SDL_image.h>
   2 #include <math.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5
   6 #include "common.h"
   7 #include "config.h"
   8 #include "file.h"
   9 #include "globals.h"
  10 #include "mt.h"
  11 #include "rocks.h"
  12
  13 struct rock rocks[MAXROCKS];
  14 Sprite *free_rocks;
  15
  16 Sprite **rock_buckets[2];
  17 int n_buckets;
  18 // we have two sets of buckets -- this variable tells which we are using.
  19 int p;
  20 int bw, bh;
  21 int grid_size;
  22
  23 static struct rock prototypes[NROCKS];
  24
  25 // timers for rock generation.
  26 static float rtimers[4];
  27
  28 uint32_t nrocks;
  29 float nrocks_timer;
  30 float nrocks_inc_ticks = 2*60*20/(F_ROCKS-I_ROCKS);
  31
  32 // constants for rock generation.
  33 #define KH (32*20)  // 32 s for a speed=1 rock to cross the screen horizontally.
  34 #define KV (24*20)  // 24 s for a speed=1 rock to cross the screen vertically.
  35 #define RDX 2.5  // range for rock dx values (+/-)
  36 #define RDY 2.5  // range for rock dy values (+/-)
  37
  38 static inline Sprite **
  39 bucket(int x, int y, int p)
  40 {
  41         int b = (x+grid_size)/grid_size + bw*((y+grid_size)/grid_size);
  42         return &rock_buckets[p][b];
  43 }
  44
  45 void
  46 init_buckets(void)
  47 {
  48         int scr_grid_w = (XSIZE+2*grid_size-1) / grid_size;
  49         int scr_grid_h = (YSIZE+2*grid_size-1) / grid_size;
  50         bw = 1 + scr_grid_w + 1;
  51         bh = 1 + scr_grid_h + 1;
  52         n_buckets = bw * bh;
  53
  54         rock_buckets[0] = malloc(n_buckets * sizeof(struct rock *));
  55         rock_buckets[1] = malloc(n_buckets * sizeof(struct rock *));
  56         if(!rock_buckets[0] || !rock_buckets[1]) {
  57                 fprintf(stderr, "Can't allocate rock buckets.\n");
  58                 exit(1);
  59         }
  60         p = 0;
  61 }
  62
  63 static inline void
  64 insert_sprite(Sprite **head, Sprite *this)
  65 {
  66         this->next = *head;
  67         *head = this;
  68 }
  69
  70 static inline Sprite *
  71 remove_sprite(Sprite **head)
  72 {
  73         Sprite *this = *head;
  74         *head = this->next;
  75         return this;
  76 }
  77
  78 void
  79 reset_rocks(void)
  80 {
  81         int i;
  82
  83         for(i=0; i<MAXROCKS; i++) rocks[i].image = NULL;
  84
  85         rocks[0].next = NULL;
  86         for(i=1; i<MAXROCKS; i++) rocks[i].next = &rocks[i-1];
  87         free_rocks = SPRITE(&rocks[MAXROCKS-1]);
  88
  89         for(i = 0; i<n_buckets; i++) {
  90                 rock_buckets[0][i] = NULL;
  91                 rock_buckets[1][i] = NULL;
  92         }
  93
  94         nrocks = I_ROCKS;
  95         nrocks_timer = 0;
  96 }
  97
  98 #define ROCK_LEN sizeof("sprites/rockXX.png")
  99
 100 int
 101 init_rocks(void)
 102 {
 103         int i;
 104         char a[ROCK_LEN];
 105         int maxw=0, maxh=0;
 106
 107         for(i = 0; i<NROCKS; i++) {
 108                 snprintf(a, ROCK_LEN, "sprites/rock%02d.png", i);
 109                 load_sprite(SPRITE(&prototypes[i]), a);
 110                 prototypes[i].type = ROCK_SPRITE;
 111                 maxw = max(maxw, prototypes[i].w);
 112                 maxh = max(maxh, prototypes[i].h);
 113         }
 114         grid_size = max(maxw, maxh) * 3 / 2;
 115         init_buckets();
 116         reset_rocks();
 117         return 0;
 118 }
 119
 120 enum { LEFT, RIGHT, TOP, BOTTOM };
 121
 122
 123 // compute the number of rocks/tick that should be coming from each side,
 124 // and the speed ranges of rocks coming from each side
 125 void
 126 rock_sides(float *ti, float *speed_min, float *speed_max)
 127 {
 128         float dx0,dx1, dy0,dy1;
 129         float hfactor, vfactor;
 130         int i;
 131
 132         for(i=0; i<4; i++) ti[i] = 0;
 133         for(i=0; i<4; i++) speed_min[i] = 0;
 134         for(i=0; i<4; i++) speed_max[i] = 0;
 135         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
 136
 137         dx0 = -RDX - screendx; dx1 = RDX - screendx;
 138         dy0 = -RDY - screendy; dy1 = RDY - screendy;
 139
 140         if(dx0 < 0) {
 141                 speed_max[RIGHT] = -dx0;
 142                 if(dx1 < 0) {
 143                         // Rocks moving left only. So the RIGHT side of the screen
 144                         speed_min[RIGHT] = -dx1;
 145                         ti[RIGHT] = -(dx0+dx1)/2;
 146                 } else {
 147                         // Rocks moving left and right
 148                         speed_max[LEFT] = dx1;
 149                         ti[RIGHT] = -dx0/2;
 150                         ti[LEFT] = dx1/2;
 151                 }
 152         } else {
 153                 // Rocks moving right only. So the LEFT side of the screen
 154                 speed_min[LEFT] = dx0;
 155                 speed_max[LEFT] = dx1;
 156                 ti[LEFT] = (dx0+dx1)/2;
 157         }
 158         ti[LEFT] *= hfactor;
 159         ti[RIGHT] *= hfactor;
 160
 161         if(dy0 < 0) {
 162                 speed_max[BOTTOM] = -dy0;
 163                 if(dy1 < 0) {
 164                         // Rocks moving up only. So the BOTTOM of the screen
 165                         speed_min[BOTTOM] = -dy1;
 166                         ti[BOTTOM] = -(dy0+dy1)/2;
 167                 } else {
 168                         // Rocks moving up and down
 169                         speed_max[TOP] = dy1;
 170                         ti[BOTTOM] = -dy0/2;
 171                         ti[TOP] = dy1/2;
 172                 }
 173         } else {
 174                 // Rocks moving down only. so the TOP of the screen
 175                 speed_min[TOP] = dy0;
 176                 speed_max[TOP] = dy1;
 177                 ti[TOP] = (dy0+dy1)/2;
 178         }
 179         ti[TOP] *= vfactor;
 180         ti[BOTTOM] *= vfactor;
 181 }
 182
 183 float
 184 weighted_rnd_range(float min, float max) {
 185         return sqrt(min * min + frnd() * (max * max - min * min));
 186 }
 187
 188 void
 189 new_rocks(void)
 190 {
 191         int i, type;
 192         struct rock *r;
 193         float ti[4];
 194         float rmin[4];
 195         float rmax[4];
 196
 197         if(nrocks < F_ROCKS) {
 198                 nrocks_timer += t_frame;
 199                 if(nrocks_timer >= nrocks_inc_ticks) {
 200                         nrocks_timer -= nrocks_inc_ticks;
 201                         nrocks++;
 202                 }
 203         }
 204
 205         rock_sides(ti, rmin, rmax);
 206
 207         // increment timers
 208         for(i=0; i<4; i++) rtimers[i] += ti[i]*t_frame;
 209
 210         // generate rocks
 211         for(i=0; i<4; i++) {
 212                 while(rtimers[i] >= 1) {
 213                         rtimers[i] -= 1;
 214                         if(!free_rocks) return;  // sorry, we ran out of rocks!
 215                         r = (struct rock *) remove_sprite(&free_rocks);
 216                         type = urnd() % NROCKS;
 217                         *r = prototypes[type];
 218                         r->type = type;
 219                         switch(i) {
 220                                 case RIGHT:
 221                                         r->x = XSIZE;
 222                                         r->y = frnd()*(YSIZE + r->image->h);
 223
 224                                         r->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 225                                         r->dy = RDY*crnd();
 226                                         break;
 227                                 case LEFT:
 228                                         r->x = -r->image->w;
 229                                         r->y = frnd()*(YSIZE + r->image->h);
 230
 231                                         r->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 232                                         r->dy = RDY*crnd();
 233                                         break;
 234                                 case BOTTOM:
 235                                         r->x = frnd()*(XSIZE + r->image->w);
 236                                         r->y = YSIZE;
 237
 238                                         r->dx = RDX*crnd();
 239                                         r->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 240                                         break;
 241                                 case TOP:
 242                                         r->x = frnd()*(XSIZE + r->image->w);
 243                                         r->y = -r->image->h;
 244
 245                                         r->dx = RDX*crnd();
 246                                         r->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 247                                         break;
 248                         }
 249                         insert_sprite(bucket(r->x, r->y, p), SPRITE(r));
 250                 }
 251         }
 252 }
 253
 254 void
 255 move_rocks(void)
 256 {
 257         int b;
 258         Sprite *r, **head;
 259
 260         // Move all the rocks
 261         for(b=0; b<n_buckets; b++) {
 262                 head=&rock_buckets[p][b]; r=*head;
 263                 while(*head) {
 264                         r=*head;
 265
 266                         // move
 267                         r->x += (r->dx - screendx)*t_frame;
 268                         r->y += (r->dy - screendy)*t_frame;
 269
 270                         // clip it, or sort it into the other bucket set
 271                         // (either way we move it out of this list).
 272                         if(r->x + r->image->w < 0 || r->x >= XSIZE
 273                                         || r->y + r->image->h < 0 || r->y >= YSIZE) {
 274                                 insert_sprite(&free_rocks, remove_sprite(head));
 275                                 r->image = NULL;
 276                         } else insert_sprite(bucket(r->x, r->y, 1-p), remove_sprite(head));
 277                 }
 278         }
 279         p = 1-p;  // switch current set of buckets.
 280 }
 281
 282 void
 283 draw_rocks(void)
 284 {
 285         int i;
 286         SDL_Rect dest;
 287
 288         for(i=0; i<MAXROCKS; i++) {
 289                 if(!rocks[i].image) continue;
 290                 dest.x = rocks[i].x; dest.y = rocks[i].y;
 291                 SDL_BlitSurface(rocks[i].image,NULL,surf_screen,&dest);
 292         }
 293 }
 294
 295 int
 296 hit_in_bucket(Sprite *r, Sprite *s)
 297 {
 298         for(; r; r=r->next) {
 299                 if(collide(r, s)) return true;
 300         }
 301         return false;
 302 }
 303
 304 int
 305 hit_rocks(Sprite *s)
 306 {
 307         int l, r, t, b;
 308         Sprite **bucket;
 309
 310         l = (s->x + grid_size) / grid_size;
 311         r = (s->x + s->w + grid_size) / grid_size;
 312         t = (s->y + grid_size) / grid_size;
 313         b = (s->y + s->h + grid_size) / grid_size;
 314         bucket = &rock_buckets[p][l + t*bw];
 315
 316         if(hit_in_bucket(*bucket, s)) return true;
 317         if(l > 0 && hit_in_bucket(*(bucket-1), s)) return true;
 318         if(t > 0 && hit_in_bucket(*(bucket-bw), s)) return true;
 319         if(l > 0 && t > 0 && hit_in_bucket(*(bucket-1-bw), s)) return true;
 320
 321         if(r > l) {
 322                 if(hit_in_bucket(*(bucket+1), s)) return true;
 323                 if(t > 0 && hit_in_bucket(*(bucket+1-bw), s)) return true;
 324         }
 325         if(b > t) {
 326                 if(hit_in_bucket(*(bucket+bw), s)) return true;
 327                 if(l > 0 && hit_in_bucket(*(bucket-1+bw), s)) return true;
 328         }
 329         if(r > l && b > t && hit_in_bucket(*(bucket+1+bw), s)) return true;
 330         return false;
 331 }
 332
 333 int
 334 pixel_hit_in_bucket(Sprite *r, float x, float y)
 335 {
 336         for(; r; r=r->next) {
 337                 if(pixel_collide(r, x, y)) return 1;
 338         }
 339         return 0;
 340 }
 341
 342 int
 343 pixel_hit_rocks(float x, float y)
 344 {
 345         int ix, iy;
 346         int l, t;
 347         Sprite **bucket;
 348
 349         ix = x + grid_size; iy = y + grid_size;
 350         l = ix / grid_size; t = iy / grid_size;
 351         bucket = &rock_buckets[p][l + t*bw];
 352         if(pixel_hit_in_bucket(*bucket, x, y)) return true;
 353         if(l > 0 && pixel_hit_in_bucket(*(bucket-1), x, y)) return true;
 354         if(t > 0 && pixel_hit_in_bucket(*(bucket-bw), x, y)) return true;
 355         if(l > 0 && t > 0 && pixel_hit_in_bucket(*(bucket-1-bw), x, y)) return true;
 356         return false;
 357 }
 358
 359 void
 360 blast_rocks(float x, float y, float radius, int onlyslow)
 361 {
 362         int b;
 363         Sprite *r;
 364         float dx, dy, n;
 365
 366         if(onlyslow) return;
 367
 368         for(b=0; b<n_buckets; b++) {
 369                 for(r=rock_buckets[p][b]; r; r=r->next) {
 370                         if(r->x <= 0) continue;
 371
 372                         // This makes it so your explosion from dying magically doesn't leave
 373                         // any rocks that aren't moving much on the x axis. If onlyslow is set,
 374                         // only rocks that are barely moving will be pushed.
 375                         if(onlyslow && (r->dx - screendx < -4 || r->dx - screendx > 3)) continue;
 376
 377                         dx = r->x - x;
 378                         dy = r->y - y;
 379
 380                         n = sqrt(dx*dx + dy*dy);
 381                         if(n < radius) {
 382                                 n *= 15;
 383                                 r->dx += 54.0*dx/n;
 384                                 r->dy += 54.0*dy/n;
 385                         }
 386                 }
 387         }
 388 }