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