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 int nrocks;
  28
  29 // constants for rock generation.
  30 #define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
  31 #define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
  32 #define RDX 2.5  // range for rock dx values (+/-)
  33 #define RDY 2.5  // range for rock dy values (+/-)
  34
  35 float rnd(void);
  36
  37 #define crnd() (2*(rnd()-0.5))
  38
  39
  40 int
  41 init_rocks(void)
  42 {
  43         int i;
  44         char a[MAX_PATH_LEN];
  45         SDL_Surface *temp;
  46
  47         for(i = 0; i<NROCKS; i++) {
  48                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  49                 NULLERROR(temp = IMG_Load(a));
  50                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
  51                 get_shape(surf_rock[i], &rock_shapes[i]);
  52         }
  53         nrocks = 41;
  54         return 0;
  55 }
  56
  57 void
  58 reset_rocks(void)
  59 {
  60         int i;
  61
  62         for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
  63 }
  64
  65 enum { LEFT, RIGHT, TOP, BOTTOM };
  66
  67 void
  68 rock_timer_increments(float *ti)
  69 {
  70         float dx0,dx1, dy0,dy1;
  71         float hfactor, vfactor;
  72         int i;
  73
  74         for(i=0; i<4; i++) ti[i] = 0;
  75         hfactor = nrocks/KH; vfactor = nrocks/KV;
  76
  77         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  78         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  79
  80         if(dx0 != 0) {
  81                 if(dx0 < 0) {
  82                         if(dx1 < 0) ti[RIGHT] = -(dx0+dx1)/2;
  83                         else {
  84                                 ti[RIGHT] = -dx0/2;
  85                                 ti[LEFT] = dx1/2;
  86                         }
  87                 } else ti[LEFT] = (dx0+dx1)/2;
  88         }
  89         ti[LEFT] *= hfactor;
  90         ti[RIGHT] *= hfactor;
  91
  92         if(dy0 != 0) {
  93                 if(dy0 < 0) {
  94                         if(dy1 < 0) ti[BOTTOM] = -(dy0+dy1)/2;
  95                         else {
  96                                 ti[BOTTOM] = -dy0/2;
  97                                 ti[TOP] = dy1/2;
  98                         }
  99                 } else ti[TOP] = (dy0+dy1)/2;
 100         }
 101         ti[TOP] *= vfactor;
 102         ti[BOTTOM] *= vfactor;
 103 }
 104
 105 void
 106 new_rocks(void)
 107 {
 108         int i,j;
 109         float ti[4];
 110         float x, y;
 111
 112         rock_timer_increments(ti);
 113
 114         for(i=0; i<4; i++) {
 115                 rtimers[i] += ti[i]*gamerate/20;
 116                 if(rtimers[i] >= 1) {
 117                         j=0;
 118                         while(rockptr->active && j<MAXROCKS) {
 119                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 120                                 j++;
 121                         }
 122                         if(!rockptr->active) {
 123                                 rtimers[i] -= 1;
 124                                 rockptr->type_number = random() % NROCKS;
 125                                 rockptr->image = surf_rock[rockptr->type_number];
 126                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 127                                 switch(i) {
 128                                         case RIGHT:
 129                                                 rockptr->x = XSIZE;
 130                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 131                                                 break;
 132                                         case LEFT:
 133                                                 rockptr->x = -rockptr->image->w;
 134                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 135                                                 break;
 136                                         case BOTTOM:
 137                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 138                                                 rockptr->y = YSIZE;
 139                                                 break;
 140                                         case TOP:
 141                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 142                                                 rockptr->y = -rockptr->image->h;
 143                                                 break;
 144                                 }
 145
 146                                 j=0;
 147                                 do {
 148                                         rockptr->dx = RDX*crnd();
 149                                         rockptr->dy = RDY*crnd();
 150                                         x = (rockptr->dx-screendx)*gamerate;
 151                                         y = (rockptr->dy-screendy)*gamerate;
 152                                         j++;
 153                                 } while(x < -rockptr->image->w || x >= XSIZE
 154                                                 || y < -rockptr->image->h || y >= YSIZE);
 155                                 if(j > 1) fprintf(stderr, "had to try %d times.\n", j);
 156
 157                                 rockptr->active = 1;
 158                         }
 159                 }
 160         }
 161 }
 162
 163 void
 164 move_rocks(void)
 165 {
 166         int i;
 167
 168         // Move all the rocks
 169         for(i = 0; i < MAXROCKS; i++) {
 170                 if(rock[i].active) {
 171                         // move
 172                         rock[i].x += (rock[i].dx-screendx)*gamerate;
 173                         rock[i].y += (rock[i].dy-screendy)*gamerate;
 174                         // clip
 175                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 176                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 177                                 rock[i].active = 0;
 178                         }
 179                 }
 180         }
 181 }
 182
 183 void
 184 draw_rocks(void)
 185 {
 186         int i;
 187         SDL_Rect src, dest;
 188
 189         src.x = 0; src.y = 0;
 190
 191         for(i = 0; i<MAXROCKS; i++) {
 192                 if(rock[i].active) {
 193                         src.w = rock[i].image->w;
 194                         src.h = rock[i].image->h;
 195
 196                         dest.w = src.w;
 197                         dest.h = src.h;
 198                         dest.x = (int) rock[i].x;
 199                         dest.y = (int) rock[i].y;
 200
 201                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 202
 203                 }
 204         }
 205 }
 206
 207 int
 208 hit_rocks(float x, float y, struct shape *shape)
 209 {
 210         int i;
 211
 212         for(i=0; i<MAXROCKS; i++) {
 213                 if(rock[i].active) {
 214                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 215                                 return 1;
 216                 }
 217         }
 218         return 0;
 219 }
 220
 221 void
 222 blast_rocks(float x, float y, float radius, int onlyslow)
 223 {
 224         int i;
 225         float dx, dy, n;
 226
 227         for(i = 0; i<MAXROCKS; i++ ) {
 228                 if(rock[i].x <= 0) continue;
 229
 230                 // This makes it so your explosion from dying magically doesn't leave
 231                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 232                 // only rocks that are barely moving will be pushed.
 233                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 234
 235                 dx = rock[i].x - x;
 236                 dy = rock[i].y - y;
 237
 238                 n = sqrt(dx*dx + dy*dy);
 239                 if(n < radius) {
 240                         n *= 20;
 241                         rock[i].dx += 54.0*(dx+30)/n;
 242                         rock[i].dy += 54.0*dy/n;
 243                 }
 244         }
 245 }