rocks.c

   1 #include <SDL_image.h>
   2 #include <math.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5
   6 #include "config.h"
   7 #include "file.h"
   8 #include "globals.h"
   9 #include "rocks.h"
  10 #include "shape.h"
  11
  12 struct rock_struct {
  13         float x,y,dx,dy;
  14         int active;
  15         SDL_Surface *image;
  16         struct shape *shape;
  17         int type_number;
  18 };
  19
  20 struct rock_struct rock[MAXROCKS], *rockptr = rock;
  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 rcnt;
  29
  30 uint32_t nrocks;
  31 uint32_t nrocks_timer;
  32 uint32_t nrocks_inc_ticks = 2*60*1000/(F_ROCKS-I_ROCKS);
  33
  34 // constants for rock generation.
  35 #define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
  36 #define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
  37 #define RDX 2.5  // range for rock dx values (+/-)
  38 #define RDY 2.5  // range for rock dy values (+/-)
  39
  40 float rnd(void);
  41
  42 #define crnd() (2*(rnd()-0.5))
  43
  44
  45 int
  46 init_rocks(void)
  47 {
  48         int i;
  49         char a[MAX_PATH_LEN];
  50         SDL_Surface *temp;
  51
  52         for(i = 0; i<NROCKS; i++) {
  53                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  54                 NULLERROR(temp = IMG_Load(a));
  55                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
  56                 get_shape(surf_rock[i], &rock_shapes[i]);
  57         }
  58         return 0;
  59 }
  60
  61 void
  62 reset_rocks(void)
  63 {
  64         int i;
  65
  66         for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
  67         nrocks = I_ROCKS;
  68         nrocks_timer = 0;
  69         rcnt = 0;
  70 }
  71
  72 enum { LEFT, RIGHT, TOP, BOTTOM };
  73
  74
  75 // compute the number of rocks/seccond that should be coming from each side
  76
  77 // compute the speed ranges of rocks coming from each side
  78 void
  79 rock_sides(float *ti, float *speed_min, float *speed_max)
  80 {
  81         float dx0,dx1, dy0,dy1;
  82         float hfactor, vfactor;
  83         int i;
  84
  85         for(i=0; i<4; i++) ti[i] = 0;
  86         for(i=0; i<4; i++) speed_min[i] = 0;
  87         for(i=0; i<4; i++) speed_max[i] = 0;
  88         hfactor = nrocks/KH; vfactor = nrocks/KV;
  89
  90         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  91         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  92
  93         if(dx0 != 0) {
  94                 if(dx0 < 0) {
  95                         speed_max[RIGHT] = -dx0;
  96                         if(dx1 < 0) {
  97                                 // Rocks moving left only. So the RIGHT side of the screen
  98                                 speed_min[RIGHT] = -dx1;
  99                                 ti[RIGHT] = -(dx0+dx1)/2;
 100                         } else {
 101                                 // Rocks moving left and right
 102                                 speed_max[LEFT] = dx1;
 103                                 ti[RIGHT] = -dx0/2;
 104                                 ti[LEFT] = dx1/2;
 105                         }
 106                 } else {
 107                         // Rocks moving right only. So the LEFT side of the screen
 108                         speed_min[LEFT] = dx0;
 109                         speed_max[LEFT] = dx1;
 110                         ti[LEFT] = (dx0+dx1)/2;
 111                 }
 112         }
 113         ti[LEFT] *= hfactor;
 114         ti[RIGHT] *= hfactor;
 115
 116         if(dy0 != 0) {
 117                 if(dy0 < 0) {
 118                         speed_max[BOTTOM] = -dy0;
 119                         if(dy1 < 0) {
 120                                 // Rocks moving up only. So the BOTTOM of the screen
 121                                 speed_min[BOTTOM] = -dy1;
 122                                 ti[BOTTOM] = -(dy0+dy1)/2;
 123                         } else {
 124                                 // Rocks moving up and down
 125                                 speed_max[TOP] = dy1;
 126                                 ti[BOTTOM] = -dy0/2;
 127                                 ti[TOP] = dy1/2;
 128                         }
 129                 } else {
 130                         // Rocks moving down only. so the TOP of the screen
 131                         speed_min[TOP] = dy0;
 132                         speed_max[TOP] = dy1;
 133                         ti[TOP] = (dy0+dy1)/2;
 134                 }
 135         }
 136         ti[TOP] *= vfactor;
 137         ti[BOTTOM] *= vfactor;
 138 }
 139
 140 float
 141 weighted_rnd_range(float min, float max) {
 142         return sqrt(min * min + rnd() * (max * max - min * min));
 143 }
 144
 145 void
 146 new_rocks(void)
 147 {
 148         int i,j;
 149         float ti[4];
 150         float rmin[4];
 151         float rmax[4];
 152
 153         if(nrocks < F_ROCKS) {
 154                 nrocks_timer += ticks_since_last;
 155                 if(nrocks_timer >= nrocks_inc_ticks) {
 156                         nrocks_timer -= nrocks_inc_ticks;
 157                         nrocks++;
 158                 }
 159         }
 160
 161         rock_sides(ti, rmin, rmax);
 162
 163         // loop through the four sides of the screen
 164         for(i=0; i<4; i++) {
 165                 // see if we generate a rock for this side this frame
 166                 rtimers[i] += ti[i]*gamerate/20;
 167                 while(rtimers[i] >= 1) {
 168                         rtimers[i] -= 1;
 169                         j=0;
 170                         while(rockptr->active && j<MAXROCKS) {
 171                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 172                                 j++;
 173                         }
 174                         if(!rockptr->active) {
 175                                 rockptr->type_number = random() % NROCKS;
 176                                 rockptr->image = surf_rock[rockptr->type_number];
 177                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 178                                 switch(i) {
 179                                         case RIGHT:
 180                                                 rockptr->x = XSIZE;
 181                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 182
 183                                                 rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 184                                                 rockptr->dy = RDY*crnd();
 185                                                 break;
 186                                         case LEFT:
 187                                                 rockptr->x = -rockptr->image->w;
 188                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 189
 190                                                 rockptr->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 191                                                 rockptr->dy = RDY*crnd();
 192                                                 break;
 193                                         case BOTTOM:
 194                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 195                                                 rockptr->y = YSIZE;
 196
 197                                                 rockptr->dx = RDX*crnd();
 198                                                 rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 199                                                 break;
 200                                         case TOP:
 201                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 202                                                 rockptr->y = -rockptr->image->h;
 203
 204                                                 rockptr->dx = RDX*crnd();
 205                                                 rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 206                                                 break;
 207                                 }
 208
 209                                 rockptr->active = 1;
 210                                 rcnt++;
 211                         }
 212                 }
 213         }
 214 }
 215
 216 void
 217 move_rocks(void)
 218 {
 219         int i;
 220
 221         // Move all the rocks
 222         for(i = 0; i < MAXROCKS; i++) {
 223                 if(rock[i].active) {
 224                         // move
 225                         rock[i].x += (rock[i].dx-screendx)*gamerate;
 226                         rock[i].y += (rock[i].dy-screendy)*gamerate;
 227                         // clip
 228                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 229                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 230                                 rock[i].active = 0;
 231                                 rcnt--;
 232                         }
 233                 }
 234         }
 235         // if(rcnt < nrocks) printf("-%d.\n", nrocks-rcnt);
 236         // else printf("%d.\n", rcnt-nrocks);
 237 }
 238
 239 void
 240 draw_rocks(void)
 241 {
 242         int i;
 243         SDL_Rect src, dest;
 244
 245         src.x = 0; src.y = 0;
 246
 247         for(i = 0; i<MAXROCKS; i++) {
 248                 if(rock[i].active) {
 249                         src.w = rock[i].image->w;
 250                         src.h = rock[i].image->h;
 251
 252                         dest.w = src.w;
 253                         dest.h = src.h;
 254                         dest.x = (int) rock[i].x;
 255                         dest.y = (int) rock[i].y;
 256
 257                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 258
 259                 }
 260         }
 261 }
 262
 263 int
 264 hit_rocks(float x, float y, struct shape *shape)
 265 {
 266         int i;
 267
 268         for(i=0; i<MAXROCKS; i++) {
 269                 if(rock[i].active) {
 270                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 271                                 return 1;
 272                 }
 273         }
 274         return 0;
 275 }
 276
 277 void
 278 blast_rocks(float x, float y, float radius, int onlyslow)
 279 {
 280         int i;
 281         float dx, dy, n;
 282
 283         if(onlyslow) return;
 284
 285         for(i = 0; i<MAXROCKS; i++ ) {
 286                 if(rock[i].x <= 0) continue;
 287
 288                 // This makes it so your explosion from dying magically doesn't leave
 289                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 290                 // only rocks that are barely moving will be pushed.
 291                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 292
 293                 dx = rock[i].x - x;
 294                 dy = rock[i].y - y;
 295
 296                 n = sqrt(dx*dx + dy*dy);
 297                 if(n < radius) {
 298                         n *= 15;
 299                         rock[i].dx += 54.0*dx/n;
 300                         rock[i].dy += 54.0*dy/n;
 301                 }
 302         }
 303 }