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 int32_t rcnt, lrcnt;
  29 int32_t rsum, rsamples;
  30 float ravg;
  31
  32 uint32_t nrocks;
  33 uint32_t nrocks_timer;
  34 uint32_t nrocks_inc_ticks = 2*60*1000/(F_ROCKS-I_ROCKS);
  35
  36 // constants for rock generation.
  37 #define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
  38 #define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
  39 #define RDX 2.5  // range for rock dx values (+/-)
  40 #define RDY 2.5  // range for rock dy values (+/-)
  41
  42 float rnd(void);
  43
  44 #define crnd() (2*(rnd()-0.5))
  45
  46
  47 int
  48 init_rocks(void)
  49 {
  50         int i;
  51         char a[MAX_PATH_LEN];
  52         SDL_Surface *temp;
  53
  54         for(i = 0; i<NROCKS; i++) {
  55                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  56                 NULLERROR(temp = IMG_Load(a));
  57                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
  58                 get_shape(surf_rock[i], &rock_shapes[i]);
  59         }
  60         return 0;
  61 }
  62
  63 void
  64 reset_rocks(void)
  65 {
  66         int i;
  67
  68         for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
  69         nrocks = I_ROCKS;
  70         nrocks_timer = 0;
  71         rcnt = 0; lrcnt = -1;
  72         rsum = 0; rsamples = 0;
  73 }
  74
  75 enum { LEFT, RIGHT, TOP, BOTTOM };
  76
  77
  78 // compute the number of rocks/seccond that should be coming from each side
  79
  80 // compute the speed ranges of rocks coming from each side
  81 void
  82 rock_sides(float *ti, float *speed_min, float *speed_max)
  83 {
  84         float dx0,dx1, dy0,dy1;
  85         float hfactor, vfactor;
  86         int i;
  87
  88         for(i=0; i<4; i++) ti[i] = 0;
  89         for(i=0; i<4; i++) speed_min[i] = 0;
  90         for(i=0; i<4; i++) speed_max[i] = 0;
  91         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
  92
  93         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  94         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  95
  96         if(dx0 != 0) {
  97                 if(dx0 < 0) {
  98                         speed_max[RIGHT] = -dx0;
  99                         if(dx1 < 0) {
 100                                 // Rocks moving left only. So the RIGHT side of the screen
 101                                 speed_min[RIGHT] = -dx1;
 102                                 ti[RIGHT] = -(dx0+dx1)/2;
 103                         } else {
 104                                 // Rocks moving left and right
 105                                 speed_max[LEFT] = dx1;
 106                                 ti[RIGHT] = -dx0/2;
 107                                 ti[LEFT] = dx1/2;
 108                         }
 109                 } else {
 110                         // Rocks moving right only. So the LEFT side of the screen
 111                         speed_min[LEFT] = dx0;
 112                         speed_max[LEFT] = dx1;
 113                         ti[LEFT] = (dx0+dx1)/2;
 114                 }
 115         }
 116         ti[LEFT] *= hfactor;
 117         ti[RIGHT] *= hfactor;
 118
 119         if(dy0 != 0) {
 120                 if(dy0 < 0) {
 121                         speed_max[BOTTOM] = -dy0;
 122                         if(dy1 < 0) {
 123                                 // Rocks moving up only. So the BOTTOM of the screen
 124                                 speed_min[BOTTOM] = -dy1;
 125                                 ti[BOTTOM] = -(dy0+dy1)/2;
 126                         } else {
 127                                 // Rocks moving up and down
 128                                 speed_max[TOP] = dy1;
 129                                 ti[BOTTOM] = -dy0/2;
 130                                 ti[TOP] = dy1/2;
 131                         }
 132                 } else {
 133                         // Rocks moving down only. so the TOP of the screen
 134                         speed_min[TOP] = dy0;
 135                         speed_max[TOP] = dy1;
 136                         ti[TOP] = (dy0+dy1)/2;
 137                 }
 138         }
 139         ti[TOP] *= vfactor;
 140         ti[BOTTOM] *= vfactor;
 141 }
 142
 143 float
 144 weighted_rnd_range(float min, float max) {
 145         return sqrt(min * min + rnd() * (max * max - min * min));
 146 }
 147
 148 void
 149 new_rocks(void)
 150 {
 151         int i,j;
 152         float ti[4];
 153         float rmin[4];
 154         float rmax[4];
 155
 156         if(nrocks < F_ROCKS) {
 157                 nrocks_timer += ticks_since_last;
 158                 if(nrocks_timer >= nrocks_inc_ticks) {
 159                         nrocks_timer -= nrocks_inc_ticks;
 160                         nrocks++;
 161                 }
 162         }
 163
 164         rock_sides(ti, rmin, rmax);
 165
 166         // loop through the four sides of the screen
 167         for(i=0; i<4; i++) {
 168                 // see if we generate a rock for this side this frame
 169                 rtimers[i] += ti[i]*gamerate/20;
 170                 while(rtimers[i] >= 1) {
 171                         rtimers[i] -= 1;
 172                         j=0;
 173                         while(rockptr->active && j<MAXROCKS) {
 174                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 175                                 j++;
 176                         }
 177                         if(!rockptr->active) {
 178                                 rockptr->type_number = random() % NROCKS;
 179                                 rockptr->image = surf_rock[rockptr->type_number];
 180                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 181                                 switch(i) {
 182                                         case RIGHT:
 183                                                 rockptr->x = XSIZE;
 184                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 185
 186                                                 rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 187                                                 rockptr->dy = RDY*crnd();
 188                                                 break;
 189                                         case LEFT:
 190                                                 rockptr->x = -rockptr->image->w;
 191                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 192
 193                                                 rockptr->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 194                                                 rockptr->dy = RDY*crnd();
 195                                                 break;
 196                                         case BOTTOM:
 197                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 198                                                 rockptr->y = YSIZE;
 199
 200                                                 rockptr->dx = RDX*crnd();
 201                                                 rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 202                                                 break;
 203                                         case TOP:
 204                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 205                                                 rockptr->y = -rockptr->image->h;
 206
 207                                                 rockptr->dx = RDX*crnd();
 208                                                 rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 209                                                 break;
 210                                 }
 211
 212                                 rockptr->active = 1;
 213                                 rcnt++;
 214                         }
 215                 }
 216         }
 217 }
 218
 219 void
 220 move_rocks(void)
 221 {
 222         int i;
 223
 224         // Move all the rocks
 225         for(i = 0; i < MAXROCKS; i++) {
 226                 if(rock[i].active) {
 227                         // move
 228                         rock[i].x += (rock[i].dx-screendx)*gamerate;
 229                         rock[i].y += (rock[i].dy-screendy)*gamerate;
 230                         // clip
 231                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 232                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 233                                 rock[i].active = 0;
 234                                 rcnt--;
 235                         }
 236                 }
 237         }
 238         /*
 239         if(lrcnt == -1 && rcnt == nrocks) lrcnt = 0;
 240         if(rcnt != lrcnt && lrcnt != -1) {
 241                 lrcnt = rcnt;
 242                 rsum += rcnt-nrocks; rsamples++;
 243                 ravg = (float) rsum / rsamples;
 244                 printf("%.2f%%\n", 100.0 * ravg / nrocks);
 245         }
 246         */
 247 }
 248
 249 void
 250 draw_rocks(void)
 251 {
 252         int i;
 253         SDL_Rect src, dest;
 254
 255         src.x = 0; src.y = 0;
 256
 257         for(i = 0; i<MAXROCKS; i++) {
 258                 if(rock[i].active) {
 259                         src.w = rock[i].image->w;
 260                         src.h = rock[i].image->h;
 261
 262                         dest.w = src.w;
 263                         dest.h = src.h;
 264                         dest.x = (int) rock[i].x;
 265                         dest.y = (int) rock[i].y;
 266
 267                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 268
 269                 }
 270         }
 271 }
 272
 273 int
 274 hit_rocks(float x, float y, struct shape *shape)
 275 {
 276         int i;
 277
 278         for(i=0; i<MAXROCKS; i++) {
 279                 if(rock[i].active) {
 280                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 281                                 return 1;
 282                 }
 283         }
 284         return 0;
 285 }
 286
 287 void
 288 blast_rocks(float x, float y, float radius, int onlyslow)
 289 {
 290         int i;
 291         float dx, dy, n;
 292
 293         if(onlyslow) return;
 294
 295         for(i = 0; i<MAXROCKS; i++ ) {
 296                 if(rock[i].x <= 0) continue;
 297
 298                 // This makes it so your explosion from dying magically doesn't leave
 299                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 300                 // only rocks that are barely moving will be pushed.
 301                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 302
 303                 dx = rock[i].x - x;
 304                 dy = rock[i].y - y;
 305
 306                 n = sqrt(dx*dx + dy*dy);
 307                 if(n < radius) {
 308                         n *= 15;
 309                         rock[i].dx += 54.0*dx/n;
 310                         rock[i].dy += 54.0*dy/n;
 311                 }
 312         }
 313 }