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 "rocks.h"
  11 #include "shape.h"
  12
  13 struct rock_struct {
  14         float x,y,dx,dy;
  15         int active;
  16         SDL_Surface *image;
  17         struct shape *shape;
  18         int type_number;
  19 };
  20
  21 struct rock_struct rock[MAXROCKS], *rockptr = rock;
  22
  23 SDL_Surface *surf_rock[NROCKS];
  24 struct shape rock_shapes[NROCKS];
  25
  26 // timers for rock generation.
  27 float rtimers[4];
  28
  29 uint32_t nrocks;
  30 uint32_t nrocks_timer;
  31 uint32_t nrocks_inc_ticks = 2*60*1000/(F_ROCKS-I_ROCKS);
  32
  33 // constants for rock generation.
  34 #define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
  35 #define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
  36 #define RDX 2.5  // range for rock dx values (+/-)
  37 #define RDY 2.5  // range for rock dy values (+/-)
  38
  39 float rnd(void);
  40
  41 #define crnd() (2*(rnd()-0.5))
  42
  43
  44 int
  45 init_rocks(void)
  46 {
  47         int i;
  48         char a[MAX_PATH_LEN];
  49         SDL_Surface *temp;
  50
  51         for(i = 0; i<NROCKS; i++) {
  52                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  53                 NULLERROR(temp = IMG_Load(a));
  54                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
  55                 get_shape(surf_rock[i], &rock_shapes[i]);
  56         }
  57         return 0;
  58 }
  59
  60 void
  61 reset_rocks(void)
  62 {
  63         int i;
  64
  65         for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
  66         nrocks = I_ROCKS;
  67         nrocks_timer = 0;
  68 }
  69
  70 enum { LEFT, RIGHT, TOP, BOTTOM };
  71
  72
  73 // compute the number of rocks/second that should be coming from each side
  74
  75 // compute the speed ranges of rocks coming from each side
  76 void
  77 rock_sides(float *ti, float *speed_min, float *speed_max)
  78 {
  79         float dx0,dx1, dy0,dy1;
  80         float hfactor, vfactor;
  81         int i;
  82
  83         for(i=0; i<4; i++) ti[i] = 0;
  84         for(i=0; i<4; i++) speed_min[i] = 0;
  85         for(i=0; i<4; i++) speed_max[i] = 0;
  86         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
  87
  88         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  89         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  90
  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         ti[LEFT] *= hfactor;
 110         ti[RIGHT] *= hfactor;
 111
 112         if(dy0 < 0) {
 113                 speed_max[BOTTOM] = -dy0;
 114                 if(dy1 < 0) {
 115                         // Rocks moving up only. So the BOTTOM of the screen
 116                         speed_min[BOTTOM] = -dy1;
 117                         ti[BOTTOM] = -(dy0+dy1)/2;
 118                 } else {
 119                         // Rocks moving up and down
 120                         speed_max[TOP] = dy1;
 121                         ti[BOTTOM] = -dy0/2;
 122                         ti[TOP] = dy1/2;
 123                 }
 124         } else {
 125                 // Rocks moving down only. so the TOP of the screen
 126                 speed_min[TOP] = dy0;
 127                 speed_max[TOP] = dy1;
 128                 ti[TOP] = (dy0+dy1)/2;
 129         }
 130         ti[TOP] *= vfactor;
 131         ti[BOTTOM] *= vfactor;
 132 }
 133
 134 float
 135 weighted_rnd_range(float min, float max) {
 136         return sqrt(min * min + rnd() * (max * max - min * min));
 137 }
 138
 139 void
 140 new_rocks(void)
 141 {
 142         int i,j;
 143         float ti[4];
 144         float rmin[4];
 145         float rmax[4];
 146
 147         if(nrocks < F_ROCKS) {
 148                 nrocks_timer += ms_frame;
 149                 if(nrocks_timer >= nrocks_inc_ticks) {
 150                         nrocks_timer -= nrocks_inc_ticks;
 151                         nrocks++;
 152                 }
 153         }
 154
 155         rock_sides(ti, rmin, rmax);
 156
 157         // loop through the four sides of the screen
 158         for(i=0; i<4; i++) {
 159                 // see if we generate a rock for this side this frame
 160                 rtimers[i] += ti[i]*t_frame/20;
 161                 while(rtimers[i] >= 1) {
 162                         rtimers[i] -= 1;
 163                         j=0;
 164                         while(rockptr->active && j<MAXROCKS) {
 165                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 166                                 j++;
 167                         }
 168                         if(!rockptr->active) {
 169                                 rockptr->type_number = random() % NROCKS;
 170                                 rockptr->image = surf_rock[rockptr->type_number];
 171                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 172                                 switch(i) {
 173                                         case RIGHT:
 174                                                 rockptr->x = XSIZE;
 175                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 176
 177                                                 rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 178                                                 rockptr->dy = RDY*crnd();
 179                                                 break;
 180                                         case LEFT:
 181                                                 rockptr->x = -rockptr->image->w;
 182                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 183
 184                                                 rockptr->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 185                                                 rockptr->dy = RDY*crnd();
 186                                                 break;
 187                                         case BOTTOM:
 188                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 189                                                 rockptr->y = YSIZE;
 190
 191                                                 rockptr->dx = RDX*crnd();
 192                                                 rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 193                                                 break;
 194                                         case TOP:
 195                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 196                                                 rockptr->y = -rockptr->image->h;
 197
 198                                                 rockptr->dx = RDX*crnd();
 199                                                 rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 200                                                 break;
 201                                 }
 202
 203                                 rockptr->active = 1;
 204                         }
 205                 }
 206         }
 207 }
 208
 209 void
 210 move_rocks(void)
 211 {
 212         int i;
 213
 214         // Move all the rocks
 215         for(i = 0; i < MAXROCKS; i++) {
 216                 if(rock[i].active) {
 217                         // move
 218                         rock[i].x += (rock[i].dx-screendx)*t_frame;
 219                         rock[i].y += (rock[i].dy-screendy)*t_frame;
 220                         // clip
 221                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 222                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 223                                 rock[i].active = 0;
 224                         }
 225                 }
 226         }
 227 }
 228
 229 void
 230 draw_rocks(void)
 231 {
 232         int i;
 233         SDL_Rect src, dest;
 234
 235         src.x = 0; src.y = 0;
 236
 237         for(i = 0; i<MAXROCKS; i++) {
 238                 if(rock[i].active) {
 239                         src.w = rock[i].image->w;
 240                         src.h = rock[i].image->h;
 241
 242                         dest.w = src.w;
 243                         dest.h = src.h;
 244                         dest.x = (int) rock[i].x;
 245                         dest.y = (int) rock[i].y;
 246
 247                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 248
 249                 }
 250         }
 251 }
 252
 253 int
 254 hit_rocks(float x, float y, struct shape *shape)
 255 {
 256         int i;
 257
 258         for(i=0; i<MAXROCKS; i++) {
 259                 if(rock[i].active) {
 260                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 261                                 return 1;
 262                 }
 263         }
 264         return 0;
 265 }
 266
 267 void
 268 blast_rocks(float x, float y, float radius, int onlyslow)
 269 {
 270         int i;
 271         float dx, dy, n;
 272
 273         if(onlyslow) return;
 274
 275         for(i = 0; i<MAXROCKS; i++ ) {
 276                 if(rock[i].x <= 0) continue;
 277
 278                 // This makes it so your explosion from dying magically doesn't leave
 279                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 280                 // only rocks that are barely moving will be pushed.
 281                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 282
 283                 dx = rock[i].x - x;
 284                 dy = rock[i].y - y;
 285
 286                 n = sqrt(dx*dx + dy*dy);
 287                 if(n < radius) {
 288                         n *= 15;
 289                         rock[i].dx += 54.0*dx/n;
 290                         rock[i].dy += 54.0*dy/n;
 291                 }
 292         }
 293 }