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 "mt.h"
  11 #include "rocks.h"
  12 #include "shape.h"
  13
  14 struct rock_struct {
  15         float x,y,dx,dy;
  16         int active;
  17         SDL_Surface *image;
  18         struct shape *shape;
  19         int type_number;
  20 };
  21
  22 struct rock_struct rock[MAXROCKS], *rockptr = rock;
  23
  24 SDL_Surface *surf_rock[NROCKS];
  25 struct shape rock_shapes[NROCKS];
  26
  27 // timers for rock generation.
  28 float rtimers[4];
  29
  30 uint32_t nrocks;
  31 uint32_t nrocks_timer;
  32 uint32_t nrocks_inc_ticks = 2*60*1000/(F_ROCKS-I_ROCKS);
  33
  34 // constants for rock generation.
  35 #define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
  36 #define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
  37 #define RDX 2.5  // range for rock dx values (+/-)
  38 #define RDY 2.5  // range for rock dy values (+/-)
  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         return 0;
  54 }
  55
  56 void
  57 reset_rocks(void)
  58 {
  59         int i;
  60
  61         for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
  62         nrocks = I_ROCKS;
  63         nrocks_timer = 0;
  64 }
  65
  66 enum { LEFT, RIGHT, TOP, BOTTOM };
  67
  68
  69 // compute the number of rocks/second that should be coming from each side
  70
  71 // compute the speed ranges of rocks coming from each side
  72 void
  73 rock_sides(float *ti, float *speed_min, float *speed_max)
  74 {
  75         float dx0,dx1, dy0,dy1;
  76         float hfactor, vfactor;
  77         int i;
  78
  79         for(i=0; i<4; i++) ti[i] = 0;
  80         for(i=0; i<4; i++) speed_min[i] = 0;
  81         for(i=0; i<4; i++) speed_max[i] = 0;
  82         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
  83
  84         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  85         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  86
  87         if(dx0 < 0) {
  88                 speed_max[RIGHT] = -dx0;
  89                 if(dx1 < 0) {
  90                         // Rocks moving left only. So the RIGHT side of the screen
  91                         speed_min[RIGHT] = -dx1;
  92                         ti[RIGHT] = -(dx0+dx1)/2;
  93                 } else {
  94                         // Rocks moving left and right
  95                         speed_max[LEFT] = dx1;
  96                         ti[RIGHT] = -dx0/2;
  97                         ti[LEFT] = dx1/2;
  98                 }
  99         } else {
 100                 // Rocks moving right only. So the LEFT side of the screen
 101                 speed_min[LEFT] = dx0;
 102                 speed_max[LEFT] = dx1;
 103                 ti[LEFT] = (dx0+dx1)/2;
 104         }
 105         ti[LEFT] *= hfactor;
 106         ti[RIGHT] *= hfactor;
 107
 108         if(dy0 < 0) {
 109                 speed_max[BOTTOM] = -dy0;
 110                 if(dy1 < 0) {
 111                         // Rocks moving up only. So the BOTTOM of the screen
 112                         speed_min[BOTTOM] = -dy1;
 113                         ti[BOTTOM] = -(dy0+dy1)/2;
 114                 } else {
 115                         // Rocks moving up and down
 116                         speed_max[TOP] = dy1;
 117                         ti[BOTTOM] = -dy0/2;
 118                         ti[TOP] = dy1/2;
 119                 }
 120         } else {
 121                 // Rocks moving down only. so the TOP of the screen
 122                 speed_min[TOP] = dy0;
 123                 speed_max[TOP] = dy1;
 124                 ti[TOP] = (dy0+dy1)/2;
 125         }
 126         ti[TOP] *= vfactor;
 127         ti[BOTTOM] *= vfactor;
 128 }
 129
 130 float
 131 weighted_rnd_range(float min, float max) {
 132         return sqrt(min * min + frnd() * (max * max - min * min));
 133 }
 134
 135 void
 136 new_rocks(void)
 137 {
 138         int i,j;
 139         float ti[4];
 140         float rmin[4];
 141         float rmax[4];
 142
 143         if(nrocks < F_ROCKS) {
 144                 nrocks_timer += ms_frame;
 145                 if(nrocks_timer >= nrocks_inc_ticks) {
 146                         nrocks_timer -= nrocks_inc_ticks;
 147                         nrocks++;
 148                 }
 149         }
 150
 151         rock_sides(ti, rmin, rmax);
 152
 153         // loop through the four sides of the screen
 154         for(i=0; i<4; i++) {
 155                 // see if we generate a rock for this side this frame
 156                 rtimers[i] += ti[i]*s_frame;
 157                 while(rtimers[i] >= 1) {
 158                         rtimers[i] -= 1;
 159                         j=0;
 160                         while(rockptr->active && j<MAXROCKS) {
 161                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 162                                 j++;
 163                         }
 164                         if(!rockptr->active) {
 165                                 rockptr->type_number = random() % NROCKS;
 166                                 rockptr->image = surf_rock[rockptr->type_number];
 167                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 168                                 switch(i) {
 169                                         case RIGHT:
 170                                                 rockptr->x = XSIZE;
 171                                                 rockptr->y = frnd()*(YSIZE + rockptr->image->h);
 172
 173                                                 rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 174                                                 rockptr->dy = RDY*crnd();
 175                                                 break;
 176                                         case LEFT:
 177                                                 rockptr->x = -rockptr->image->w;
 178                                                 rockptr->y = frnd()*(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 BOTTOM:
 184                                                 rockptr->x = frnd()*(XSIZE + rockptr->image->w);
 185                                                 rockptr->y = YSIZE;
 186
 187                                                 rockptr->dx = RDX*crnd();
 188                                                 rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 189                                                 break;
 190                                         case TOP:
 191                                                 rockptr->x = frnd()*(XSIZE + rockptr->image->w);
 192                                                 rockptr->y = -rockptr->image->h;
 193
 194                                                 rockptr->dx = RDX*crnd();
 195                                                 rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 196                                                 break;
 197                                 }
 198
 199                                 rockptr->active = 1;
 200                         }
 201                 }
 202         }
 203 }
 204
 205 void
 206 move_rocks(void)
 207 {
 208         int i;
 209
 210         // Move all the rocks
 211         for(i = 0; i < MAXROCKS; i++) {
 212                 if(rock[i].active) {
 213                         // move
 214                         rock[i].x += (rock[i].dx-screendx)*t_frame;
 215                         rock[i].y += (rock[i].dy-screendy)*t_frame;
 216                         // clip
 217                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 218                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 219                                 rock[i].active = 0;
 220                         }
 221                 }
 222         }
 223 }
 224
 225 void
 226 draw_rocks(void)
 227 {
 228         int i;
 229         SDL_Rect src, dest;
 230
 231         src.x = 0; src.y = 0;
 232
 233         for(i = 0; i<MAXROCKS; i++) {
 234                 if(rock[i].active) {
 235                         src.w = rock[i].image->w;
 236                         src.h = rock[i].image->h;
 237
 238                         dest.w = src.w;
 239                         dest.h = src.h;
 240                         dest.x = (int) rock[i].x;
 241                         dest.y = (int) rock[i].y;
 242
 243                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 244
 245                 }
 246         }
 247 }
 248
 249 int
 250 hit_rocks(float x, float y, struct shape *shape)
 251 {
 252         int i;
 253
 254         for(i=0; i<MAXROCKS; i++) {
 255                 if(rock[i].active) {
 256                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 257                                 return 1;
 258                 }
 259         }
 260         return 0;
 261 }
 262
 263 void
 264 blast_rocks(float x, float y, float radius, int onlyslow)
 265 {
 266         int i;
 267         float dx, dy, n;
 268
 269         if(onlyslow) return;
 270
 271         for(i = 0; i<MAXROCKS; i++ ) {
 272                 if(rock[i].x <= 0) continue;
 273
 274                 // This makes it so your explosion from dying magically doesn't leave
 275                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 276                 // only rocks that are barely moving will be pushed.
 277                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 278
 279                 dx = rock[i].x - x;
 280                 dy = rock[i].y - y;
 281
 282                 n = sqrt(dx*dx + dy*dy);
 283                 if(n < radius) {
 284                         n *= 15;
 285                         rock[i].dx += 54.0*dx/n;
 286                         rock[i].dy += 54.0*dy/n;
 287                 }
 288         }
 289 }