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 struct rock_struct {
  15         struct rock_struct *next;
  16         float x,y,dx,dy;
  17         SDL_Surface *image;
  18         struct shape *shape;
  19         int type_number;
  20 };
  21
  22 struct rock_struct rocks[MAXROCKS], *free_rocks;
  23
  24 struct rock_struct **rock_buckets[2];
  25 int n_buckets, p;
  26 int bw, bh;
  27 int grid_size;
  28
  29 SDL_Surface *surf_rock[NROCKS];
  30 struct shape rock_shapes[NROCKS];
  31
  32 // timers for rock generation.
  33 float rtimers[4];
  34
  35 uint32_t nrocks;
  36 float nrocks_timer;
  37 float nrocks_inc_ticks = 2*60*20/(F_ROCKS-I_ROCKS);
  38
  39 // constants for rock generation.
  40 #define KH (32.0*20)  // 32 s for a speed=1 rock to cross the screen horizontally.
  41 #define KV (24.0*20)  // 24 s for a speed=1 rock to cross the screen vertically.
  42 #define RDX 2.5  // range for rock dx values (+/-)
  43 #define RDY 2.5  // range for rock dy values (+/-)
  44
  45 static inline int bucket(int x, int y) { return (1+x/grid_size) + bw*(1+y/grid_size); }
  46
  47 void
  48 init_buckets(void)
  49 {
  50         bw = (XSIZE+2*grid_size-1) / grid_size;
  51         bh = (YSIZE+2*grid_size-1) / grid_size;
  52         n_buckets = bw * bh;
  53
  54         rock_buckets[0] = malloc(n_buckets * sizeof(struct rock_struct *));
  55         rock_buckets[1] = malloc(n_buckets * sizeof(struct rock_struct *));
  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 sort_rock(struct rock_struct *q, struct rock_struct *r, int p)
  65 {
  66         int b = bucket(r->x, r->y);
  67         q->next = r->next;  // remove from old list
  68         r->next = rock_buckets[p][b];  // insert into new list
  69         rock_buckets[p][b] = r;
  70 }
  71
  72 void
  73 reset_rocks(void)
  74 {
  75         int i;
  76
  77         for(i=0; i<MAXROCKS; i++) rocks[i].image = NULL;
  78         rocks[0].next = NULL; free_rocks = &rocks[MAXROCKS-1];
  79         for(i = 1; i<MAXROCKS; i++) rocks[i].next = &rocks[i-1];
  80         for(i = 0; i<n_buckets; i++) {
  81                 rock_buckets[0][i] = NULL;
  82                 rock_buckets[1][i] = NULL;
  83         }
  84
  85         nrocks = I_ROCKS;
  86         nrocks_timer = 0;
  87 }
  88
  89 int
  90 init_rocks(void)
  91 {
  92         int i;
  93         char a[MAX_PATH_LEN];
  94         SDL_Surface *temp;
  95         int maxw=0, maxh=0;
  96
  97         for(i = 0; i<NROCKS; i++) {
  98                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  99                 NULLERROR(temp = IMG_Load(a));
 100                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
 101                 get_shape(surf_rock[i], &rock_shapes[i]);
 102                 maxw = max(maxw, rock_shapes[i].w);
 103                 maxh = max(maxh, rock_shapes[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;
 183         struct rock_struct *r;
 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;
 207                         r->type_number = urnd() % NROCKS;
 208                         r->image = surf_rock[r->type_number];
 209                         r->shape = &rock_shapes[r->type_number];
 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                         sort_rock((struct rock_struct *)&free_rocks, r, p);
 241                 }
 242         }
 243 }
 244
 245 void
 246 move_rocks(void)
 247 {
 248         int b;
 249         struct rock_struct *q,*r;
 250
 251         // Move all the rocks
 252         for(b=0; b<n_buckets; b++) {
 253                 q=(struct rock_struct *)&rock_buckets[p][b]; r=q->next;
 254                 while(r) {
 255                         // move
 256                         r->x += (r->dx - screendx)*t_frame;
 257                         r->y += (r->dy - screendy)*t_frame;
 258
 259                         // clip
 260                         if(r->x + r->image->w < 0 || r->x >= XSIZE
 261                                         || r->y + r->image->h < 0 || r->y >= YSIZE) {
 262                                 q->next = r->next;
 263                                 r->next = free_rocks; free_rocks = r;
 264                                 r->image = NULL;
 265                         } else sort_rock(q,r,1-p);
 266                         if(q->next == r) q = q->next;
 267                         if(q) r = q->next; else r = NULL;
 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(int b, float x, float y, struct shape *shape)
 288 {
 289         struct rock_struct *r;
 290
 291         for(r=rock_buckets[p][b]; r; r=r->next) {
 292                 if(collide(x - r->x, y - r->y, r->shape, shape)) return 1;
 293         }
 294         return 0;
 295 }
 296
 297 int
 298 hit_rocks(float x, float y, struct shape *shape)
 299 {
 300         int b = bucket(x, y);
 301         int bdx = ((int)x+shape->w)/grid_size - (int)x/grid_size;
 302         int bdy = ((int)y+shape->h)/grid_size - (int)y/grid_size;
 303         if(hit_in_bucket(b, x, y, shape)) return 1;
 304         if(hit_in_bucket(b-1, x, y, shape)) return 1;
 305         if(hit_in_bucket(b-bw, x, y, shape)) return 1;
 306         if(hit_in_bucket(b-bw-1, x, y, shape)) return 1;
 307
 308         if(bdx) {
 309                 if(hit_in_bucket(b+1, x, y, shape)) return 1;
 310                 if(hit_in_bucket(b+1-bw, x, y, shape)) return 1;
 311         }
 312         if(bdy) {
 313                 if(hit_in_bucket(b+bw, x, y, shape)) return 1;
 314                 if(hit_in_bucket(b+bw-1, x, y, shape)) return 1;
 315         }
 316         if(bdx && bdy && hit_in_bucket(b+bw+1, x, y, shape)) return 1;
 317         return 0;
 318 }
 319
 320 int
 321 pixel_hit_in_bucket(int b, float x, float y)
 322 {
 323         struct rock_struct *r;
 324         for(r=rock_buckets[p][b]; r; r=r->next) {
 325                 if(x < r->x || y < r->y) continue;
 326                 if(pixel_collide(x - r->x, y - r->y, r->shape)) return 1;
 327         }
 328         return 0;
 329 }
 330
 331 int
 332 pixel_hit_rocks(float x, float y)
 333 {
 334         int b = bucket(x, y);
 335         if(pixel_hit_in_bucket(b, x, y)) return 1;
 336         if(pixel_hit_in_bucket(b-1, x, y)) return 1;
 337         if(pixel_hit_in_bucket(b-bw, x, y)) return 1;
 338         if(pixel_hit_in_bucket(b-bw-1, x, y)) return 1;
 339         return 0;
 340 }
 341
 342 void
 343 blast_rocks(float x, float y, float radius, int onlyslow)
 344 {
 345         int b;
 346         struct rock_struct *r;
 347         float dx, dy, n;
 348
 349         if(onlyslow) return;
 350
 351         for(b=0; b<n_buckets; b++) {
 352                 for(r=rock_buckets[p][b]; r; r=r->next) {
 353                         if(r->x <= 0) continue;
 354
 355                         // This makes it so your explosion from dying magically doesn't leave
 356                         // any rocks that aren't moving much on the x axis. If onlyslow is set,
 357                         // only rocks that are barely moving will be pushed.
 358                         if(onlyslow && (r->dx - screendx < -4 || r->dx - screendx > 3)) continue;
 359
 360                         dx = r->x - x;
 361                         dy = r->y - y;
 362
 363                         n = sqrt(dx*dx + dy*dy);
 364                         if(n < radius) {
 365                                 n *= 15;
 366                                 r->dx += 54.0*dx/n;
 367                                 r->dy += 54.0*dy/n;
 368                         }
 369                 }
 370         }
 371 }