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 SDL_Surface *surf_rock[NROCKS];
  23 struct shape rock_shapes[NROCKS];
  24
  25 // timers for rock generation.
  26 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 struct rock **
  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 void
  64 transfer_rock(struct rock *r, struct rock **from, struct rock **to)
  65 {
  66         *from = &r->next->rock;
  67         r->next = SPRITE(*to);
  68         *to = r;
  69 }
  70
  71 void
  72 reset_rocks(void)
  73 {
  74         int i;
  75
  76         for(i=0; i<MAXROCKS; i++) rocks[i].image = NULL;
  77         rocks[0].next = NULL; free_rocks = &rocks[MAXROCKS-1];
  78         for(i = 1; i<MAXROCKS; i++) rocks[i].next = SPRITE(&rocks[i-1]);
  79         for(i = 0; i<n_buckets; i++) {
  80                 rock_buckets[0][i] = NULL;
  81                 rock_buckets[1][i] = NULL;
  82         }
  83
  84         nrocks = I_ROCKS;
  85         nrocks_timer = 0;
  86 }
  87
  88 #define ROCK_LEN sizeof("sprites/rockXX.png")
  89
  90 int
  91 init_rocks(void)
  92 {
  93         int i;
  94         char a[ROCK_LEN];
  95         int maxw=0, maxh=0;
  96
  97         for(i = 0; i<NROCKS; i++) {
  98                 snprintf(a, ROCK_LEN, "sprites/rock%02d.png", i);
  99                 NULLERROR(surf_rock[i] = load_image(a));
 100                 get_shape(surf_rock[i], &rock_shapes[i]);
 101                 maxw = max(maxw, rock_shapes[i].w);
 102                 maxh = max(maxh, rock_shapes[i].h);
 103         }
 104         grid_size = max(maxw, maxh) * 3 / 2;
 105         init_buckets();
 106         reset_rocks();
 107         return 0;
 108 }
 109
 110 enum { LEFT, RIGHT, TOP, BOTTOM };
 111
 112
 113 // compute the number of rocks/tick that should be coming from each side,
 114 // and the speed ranges of rocks coming from each side
 115 void
 116 rock_sides(float *ti, float *speed_min, float *speed_max)
 117 {
 118         float dx0,dx1, dy0,dy1;
 119         float hfactor, vfactor;
 120         int i;
 121
 122         for(i=0; i<4; i++) ti[i] = 0;
 123         for(i=0; i<4; i++) speed_min[i] = 0;
 124         for(i=0; i<4; i++) speed_max[i] = 0;
 125         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
 126
 127         dx0 = -RDX - screendx; dx1 = RDX - screendx;
 128         dy0 = -RDY - screendy; dy1 = RDY - screendy;
 129
 130         if(dx0 < 0) {
 131                 speed_max[RIGHT] = -dx0;
 132                 if(dx1 < 0) {
 133                         // Rocks moving left only. So the RIGHT side of the screen
 134                         speed_min[RIGHT] = -dx1;
 135                         ti[RIGHT] = -(dx0+dx1)/2;
 136                 } else {
 137                         // Rocks moving left and right
 138                         speed_max[LEFT] = dx1;
 139                         ti[RIGHT] = -dx0/2;
 140                         ti[LEFT] = dx1/2;
 141                 }
 142         } else {
 143                 // Rocks moving right only. So the LEFT side of the screen
 144                 speed_min[LEFT] = dx0;
 145                 speed_max[LEFT] = dx1;
 146                 ti[LEFT] = (dx0+dx1)/2;
 147         }
 148         ti[LEFT] *= hfactor;
 149         ti[RIGHT] *= hfactor;
 150
 151         if(dy0 < 0) {
 152                 speed_max[BOTTOM] = -dy0;
 153                 if(dy1 < 0) {
 154                         // Rocks moving up only. So the BOTTOM of the screen
 155                         speed_min[BOTTOM] = -dy1;
 156                         ti[BOTTOM] = -(dy0+dy1)/2;
 157                 } else {
 158                         // Rocks moving up and down
 159                         speed_max[TOP] = dy1;
 160                         ti[BOTTOM] = -dy0/2;
 161                         ti[TOP] = dy1/2;
 162                 }
 163         } else {
 164                 // Rocks moving down only. so the TOP of the screen
 165                 speed_min[TOP] = dy0;
 166                 speed_max[TOP] = dy1;
 167                 ti[TOP] = (dy0+dy1)/2;
 168         }
 169         ti[TOP] *= vfactor;
 170         ti[BOTTOM] *= vfactor;
 171 }
 172
 173 float
 174 weighted_rnd_range(float min, float max) {
 175         return sqrt(min * min + frnd() * (max * max - min * min));
 176 }
 177
 178 void
 179 new_rocks(void)
 180 {
 181         int i;
 182         struct rock *r;
 183         float ti[4];
 184         float rmin[4];
 185         float rmax[4];
 186
 187         if(nrocks < F_ROCKS) {
 188                 nrocks_timer += t_frame;
 189                 if(nrocks_timer >= nrocks_inc_ticks) {
 190                         nrocks_timer -= nrocks_inc_ticks;
 191                         nrocks++;
 192                 }
 193         }
 194
 195         rock_sides(ti, rmin, rmax);
 196
 197         // increment timers
 198         for(i=0; i<4; i++) rtimers[i] += ti[i]*t_frame;
 199
 200         // generate rocks
 201         for(i=0; i<4; i++) {
 202                 while(rtimers[i] >= 1) {
 203                         rtimers[i] -= 1;
 204                         if(!free_rocks) return;  // sorry, we ran out of rocks!
 205                         r = free_rocks;
 206                         r->type = urnd() % NROCKS;
 207                         r->image = surf_rock[r->type];
 208                         r->shape = &rock_shapes[r->type];
 209                         switch(i) {
 210                                 case RIGHT:
 211                                         r->x = XSIZE;
 212                                         r->y = frnd()*(YSIZE + r->image->h);
 213
 214                                         r->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 215                                         r->dy = RDY*crnd();
 216                                         break;
 217                                 case LEFT:
 218                                         r->x = -r->image->w;
 219                                         r->y = frnd()*(YSIZE + r->image->h);
 220
 221                                         r->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 222                                         r->dy = RDY*crnd();
 223                                         break;
 224                                 case BOTTOM:
 225                                         r->x = frnd()*(XSIZE + r->image->w);
 226                                         r->y = YSIZE;
 227
 228                                         r->dx = RDX*crnd();
 229                                         r->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 230                                         break;
 231                                 case TOP:
 232                                         r->x = frnd()*(XSIZE + r->image->w);
 233                                         r->y = -r->image->h;
 234
 235                                         r->dx = RDX*crnd();
 236                                         r->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 237                                         break;
 238                         }
 239                         transfer_rock(r, &free_rocks, bucket(r->x, r->y, p));
 240                 }
 241         }
 242 }
 243
 244 void
 245 move_rocks(void)
 246 {
 247         int b;
 248         struct rock **head;
 249         struct rock *r;
 250
 251         // Move all the rocks
 252         for(b=0; b<n_buckets; b++) {
 253                 head=&rock_buckets[p][b]; r=*head;
 254                 while(*head) {
 255                         r=*head;
 256
 257                         // move
 258                         r->x += (r->dx - screendx)*t_frame;
 259                         r->y += (r->dy - screendy)*t_frame;
 260
 261                         // clip it, or sort it into the other bucket set
 262                         // (either way we move it out of this list).
 263                         if(r->x + r->image->w < 0 || r->x >= XSIZE
 264                                         || r->y + r->image->h < 0 || r->y >= YSIZE) {
 265                                 transfer_rock(r, head, &free_rocks);
 266                                 r->image = NULL;
 267                         } else transfer_rock(r, head, bucket(r->x, r->y, 1-p));
 268                 }
 269         }
 270         p = 1-p;  // switch current set of buckets.
 271 }
 272
 273 void
 274 draw_rocks(void)
 275 {
 276         int i;
 277         SDL_Rect dest;
 278
 279         for(i=0; i<MAXROCKS; i++) {
 280                 if(!rocks[i].image) continue;
 281                 dest.x = rocks[i].x; dest.y = rocks[i].y;
 282                 SDL_BlitSurface(rocks[i].image,NULL,surf_screen,&dest);
 283         }
 284 }
 285
 286 int
 287 hit_in_bucket(struct rock *r, Sprite *s)
 288 {
 289         for(; r; r=&r->next->rock) {
 290                 if(collide(SPRITE(r), s)) return true;
 291         }
 292         return false;
 293 }
 294
 295 int
 296 hit_rocks(Sprite *s)
 297 {
 298         struct base_sprite *sp = &s->sprite;
 299         int l, r, t, b;
 300         struct rock **bucket;
 301
 302         l = (sp->x + grid_size) / grid_size;
 303         r = (sp->x + sp->shape->w + grid_size) / grid_size;
 304         t = (sp->y + grid_size) / grid_size;
 305         b = (sp->y + sp->shape->h + grid_size) / grid_size;
 306         bucket = &rock_buckets[p][l + t*bw];
 307
 308         if(hit_in_bucket(*bucket, s)) return true;
 309         if(l > 0 && hit_in_bucket(*(bucket-1), s)) return true;
 310         if(t > 0 && hit_in_bucket(*(bucket-bw), s)) return true;
 311         if(l > 0 && t > 0 && hit_in_bucket(*(bucket-1-bw), s)) return true;
 312
 313         if(r > l) {
 314                 if(hit_in_bucket(*(bucket+1), s)) return true;
 315                 if(t > 0 && hit_in_bucket(*(bucket+1-bw), s)) return true;
 316         }
 317         if(b > t) {
 318                 if(hit_in_bucket(*(bucket+bw), s)) return true;
 319                 if(l > 0 && hit_in_bucket(*(bucket-1+bw), s)) return true;
 320         }
 321         if(r > l && b > t && hit_in_bucket(*(bucket+1+bw), s)) return true;
 322         return false;
 323 }
 324
 325 int
 326 pixel_hit_in_bucket(struct rock *r, float x, float y)
 327 {
 328         for(; r; r=&r->next->rock) {
 329                 if(x < r->x || y < r->y) continue;
 330                 if(pixel_collide(x - r->x, y - r->y, r->shape)) 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->rock) {
 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 }