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