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