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 void
  72 rock_timer_increments(float *ti)
  73 {
  74         float dx0,dx1, dy0,dy1;
  75         float hfactor, vfactor;
  76         int i;
  77
  78         for(i=0; i<4; i++) ti[i] = 0;
  79         hfactor = nrocks/KH; vfactor = nrocks/KV;
  80
  81         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  82         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  83
  84         if(dx0 != 0) {
  85                 if(dx0 < 0) {
  86                         if(dx1 < 0) ti[RIGHT] = -(dx0+dx1)/2;
  87                         else {
  88                                 ti[RIGHT] = -dx0/2;
  89                                 ti[LEFT] = dx1/2;
  90                         }
  91                 } else ti[LEFT] = (dx0+dx1)/2;
  92         }
  93         ti[LEFT] *= hfactor;
  94         ti[RIGHT] *= hfactor;
  95
  96         if(dy0 != 0) {
  97                 if(dy0 < 0) {
  98                         if(dy1 < 0) ti[BOTTOM] = -(dy0+dy1)/2;
  99                         else {
 100                                 ti[BOTTOM] = -dy0/2;
 101                                 ti[TOP] = dy1/2;
 102                         }
 103                 } else ti[TOP] = (dy0+dy1)/2;
 104         }
 105         ti[TOP] *= vfactor;
 106         ti[BOTTOM] *= vfactor;
 107 }
 108
 109 void
 110 new_rocks(void)
 111 {
 112         int i,j;
 113         float ti[4];
 114
 115         if(nrocks < F_ROCKS) {
 116                 nrocks_timer += ticks_since_last;
 117                 if(nrocks_timer >= nrocks_inc_ticks) {
 118                         nrocks_timer -= nrocks_inc_ticks;
 119                         nrocks++;
 120                 }
 121         }
 122
 123         rock_timer_increments(ti);
 124
 125         for(i=0; i<4; i++) {
 126                 rtimers[i] += ti[i]*gamerate/20;
 127                 if(rtimers[i] >= 1) {
 128                         j=0;
 129                         while(rockptr->active && j<MAXROCKS) {
 130                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 131                                 j++;
 132                         }
 133                         if(!rockptr->active) {
 134                                 rtimers[i] -= 1;
 135                                 rockptr->type_number = random() % NROCKS;
 136                                 rockptr->image = surf_rock[rockptr->type_number];
 137                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 138                                 switch(i) {
 139                                         case RIGHT:
 140                                                 rockptr->x = XSIZE;
 141                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 142                                                 break;
 143                                         case LEFT:
 144                                                 rockptr->x = -rockptr->image->w;
 145                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 146                                                 break;
 147                                         case BOTTOM:
 148                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 149                                                 rockptr->y = YSIZE;
 150                                                 break;
 151                                         case TOP:
 152                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 153                                                 rockptr->y = -rockptr->image->h;
 154                                                 break;
 155                                 }
 156
 157                                 rockptr->dx = RDX*crnd();
 158                                 rockptr->dy = RDY*crnd();
 159
 160                                 rockptr->active = 1;
 161                         }
 162                 }
 163         }
 164 }
 165
 166 void
 167 move_rocks(void)
 168 {
 169         int i;
 170
 171         // Move all the rocks
 172         for(i = 0; i < MAXROCKS; i++) {
 173                 if(rock[i].active) {
 174                         // move
 175                         rock[i].x += (rock[i].dx-screendx)*gamerate;
 176                         rock[i].y += (rock[i].dy-screendy)*gamerate;
 177                         // clip
 178                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 179                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 180                                 rock[i].active = 0;
 181                         }
 182                 }
 183         }
 184 }
 185
 186 void
 187 draw_rocks(void)
 188 {
 189         int i;
 190         SDL_Rect src, dest;
 191
 192         src.x = 0; src.y = 0;
 193
 194         for(i = 0; i<MAXROCKS; i++) {
 195                 if(rock[i].active) {
 196                         src.w = rock[i].image->w;
 197                         src.h = rock[i].image->h;
 198
 199                         dest.w = src.w;
 200                         dest.h = src.h;
 201                         dest.x = (int) rock[i].x;
 202                         dest.y = (int) rock[i].y;
 203
 204                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 205
 206                 }
 207         }
 208 }
 209
 210 int
 211 hit_rocks(float x, float y, struct shape *shape)
 212 {
 213         int i;
 214
 215         for(i=0; i<MAXROCKS; i++) {
 216                 if(rock[i].active) {
 217                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 218                                 return 1;
 219                 }
 220         }
 221         return 0;
 222 }
 223
 224 void
 225 blast_rocks(float x, float y, float radius, int onlyslow)
 226 {
 227         int i;
 228         float dx, dy, n;
 229
 230         if(onlyslow) return;
 231
 232         for(i = 0; i<MAXROCKS; i++ ) {
 233                 if(rock[i].x <= 0) continue;
 234
 235                 // This makes it so your explosion from dying magically doesn't leave
 236                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 237                 // only rocks that are barely moving will be pushed.
 238                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 239
 240                 dx = rock[i].x - x;
 241                 dy = rock[i].y - y;
 242
 243                 n = sqrt(dx*dx + dy*dy);
 244                 if(n < radius) {
 245                         n *= 15;
 246                         rock[i].dx += 54.0*dx/n;
 247                         rock[i].dy += 54.0*dy/n;
 248                 }
 249         }
 250 }