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         int i;
  72
  73         for(i=0; i<4; i++) ti[i] = 0;
  74
  75         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  76         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  77
  78         if(dx0 != 0) {
  79                 if(dx0 < 0) {
  80                         if(dx1 < 0) ti[RIGHT] = -(dx0+dx1)/2;
  81                         else {
  82                                 ti[RIGHT] = -dx0/2;
  83                                 ti[LEFT] = dx1/2;
  84                         }
  85                 } else ti[LEFT] = (dx0+dx1)/2;
  86         }
  87
  88         if(dy0 != 0) {
  89                 if(dy0 < 0) {
  90                         if(dy1 < 0) ti[BOTTOM] = -(dy0+dy1)/2;
  91                         else {
  92                                 ti[BOTTOM] = -dy0/2;
  93                                 ti[TOP] = dy1/2;
  94                         }
  95                 } else ti[TOP] = (dy0+dy1)/2;
  96         }
  97 }
  98
  99 void
 100 new_rocks(void)
 101 {
 102         int i,j;
 103         float ti[4];
 104         float x, y;
 105
 106         rock_timer_increments(ti);
 107
 108         for(i=0; i<4; i++) {
 109                 rtimers[i] += ti[i]*gamerate/20;
 110                 if(rtimers[i] >= 1) {
 111                         j=0;
 112                         while(rockptr->active && j<MAXROCKS) {
 113                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 114                                 j++;
 115                         }
 116                         if(!rockptr->active) {
 117                                 rtimers[i] -= 1;
 118                                 rockptr->type_number = random() % NROCKS;
 119                                 rockptr->image = surf_rock[rockptr->type_number];
 120                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 121                                 switch(i) {
 122                                         case RIGHT:
 123                                                 rockptr->x = XSIZE;
 124                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 125                                                 break;
 126                                         case LEFT:
 127                                                 rockptr->x = -rockptr->image->w;
 128                                                 rockptr->y = rnd()*(YSIZE + rockptr->image->h);
 129                                                 break;
 130                                         case BOTTOM:
 131                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 132                                                 rockptr->y = YSIZE;
 133                                                 break;
 134                                         case TOP:
 135                                                 rockptr->x = rnd()*(XSIZE + rockptr->image->w);
 136                                                 rockptr->y = -rockptr->image->h;
 137                                                 break;
 138                                 }
 139
 140                                 j=0;
 141                                 do {
 142                                         rockptr->dx = RDX*crnd();
 143                                         rockptr->dy = RDY*crnd();
 144                                         x = (rockptr->dx-screendx)*gamerate;
 145                                         y = (rockptr->dy-screendy)*gamerate;
 146                                         j++;
 147                                 } while(x < -rockptr->image->w || x >= XSIZE
 148                                                 || y < -rockptr->image->h || y >= YSIZE);
 149                                 if(j > 1) printf("had to try %d times.\n", j);
 150
 151                                 rockptr->active = 1;
 152                         }
 153                 }
 154         }
 155 }
 156
 157 void
 158 move_rocks(void)
 159 {
 160         int i;
 161
 162         // Move all the rocks
 163         for(i = 0; i < MAXROCKS; i++) {
 164                 if(rock[i].active) {
 165                         // move
 166                         rock[i].x += (rock[i].dx-screendx)*gamerate;
 167                         rock[i].y += (rock[i].dy-screendy)*gamerate;
 168                         // clip
 169                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 170                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 171                                 rock[i].active = 0;
 172                         }
 173                 }
 174         }
 175 }
 176
 177 void
 178 draw_rocks(void)
 179 {
 180         int i;
 181         SDL_Rect src, dest;
 182
 183         src.x = 0; src.y = 0;
 184
 185         for(i = 0; i<MAXROCKS; i++) {
 186                 if(rock[i].active) {
 187                         src.w = rock[i].image->w;
 188                         src.h = rock[i].image->h;
 189
 190                         dest.w = src.w;
 191                         dest.h = src.h;
 192                         dest.x = (int) rock[i].x;
 193                         dest.y = (int) rock[i].y;
 194
 195                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 196
 197                 }
 198         }
 199 }
 200
 201 int
 202 hit_rocks(float x, float y, struct shape *shape)
 203 {
 204         int i;
 205
 206         for(i=0; i<MAXROCKS; i++) {
 207                 if(rock[i].active) {
 208                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 209                                 return 1;
 210                 }
 211         }
 212         return 0;
 213 }
 214
 215 void
 216 blast_rocks(float x, float y, float radius, int onlyslow)
 217 {
 218         int i;
 219         float dx, dy, n;
 220
 221         for(i = 0; i<MAXROCKS; i++ ) {
 222                 if(rock[i].x <= 0) continue;
 223
 224                 // This makes it so your explosion from dying magically doesn't leave
 225                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 226                 // only rocks that are barely moving will be pushed.
 227                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 228
 229                 dx = rock[i].x - x;
 230                 dy = rock[i].y - y;
 231
 232                 n = sqrt(dx*dx + dy*dy);
 233                 if(n < radius) {
 234                         n *= 20;
 235                         rock[i].dx += 54.0*(dx+30)/n;
 236                         rock[i].dy += 54.0*dy/n;
 237                 }
 238         }
 239 }