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 float nrocks_timer;
  32 float nrocks_inc_ticks = 2*60*20/(F_ROCKS-I_ROCKS);
  33
  34 // constants for rock generation.
  35 #define KH (32.0*20)  // 32 s for a speed=1 rock to cross the screen horizontally.
  36 #define KV (24.0*20)  // 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         reset_rocks();
  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         nrocks = I_ROCKS;
  64         nrocks_timer = 0;
  65 }
  66
  67 enum { LEFT, RIGHT, TOP, BOTTOM };
  68
  69
  70 // compute the number of rocks/second that should be coming from each side
  71
  72 // compute the speed ranges of rocks coming from each side
  73 void
  74 rock_sides(float *ti, float *speed_min, float *speed_max)
  75 {
  76         float dx0,dx1, dy0,dy1;
  77         float hfactor, vfactor;
  78         int i;
  79
  80         for(i=0; i<4; i++) ti[i] = 0;
  81         for(i=0; i<4; i++) speed_min[i] = 0;
  82         for(i=0; i<4; i++) speed_max[i] = 0;
  83         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
  84
  85         dx0 = -RDX - screendx; dx1 = RDX - screendx;
  86         dy0 = -RDY - screendy; dy1 = RDY - screendy;
  87
  88         if(dx0 < 0) {
  89                 speed_max[RIGHT] = -dx0;
  90                 if(dx1 < 0) {
  91                         // Rocks moving left only. So the RIGHT side of the screen
  92                         speed_min[RIGHT] = -dx1;
  93                         ti[RIGHT] = -(dx0+dx1)/2;
  94                 } else {
  95                         // Rocks moving left and right
  96                         speed_max[LEFT] = dx1;
  97                         ti[RIGHT] = -dx0/2;
  98                         ti[LEFT] = dx1/2;
  99                 }
 100         } else {
 101                 // Rocks moving right only. So the LEFT side of the screen
 102                 speed_min[LEFT] = dx0;
 103                 speed_max[LEFT] = dx1;
 104                 ti[LEFT] = (dx0+dx1)/2;
 105         }
 106         ti[LEFT] *= hfactor;
 107         ti[RIGHT] *= hfactor;
 108
 109         if(dy0 < 0) {
 110                 speed_max[BOTTOM] = -dy0;
 111                 if(dy1 < 0) {
 112                         // Rocks moving up only. So the BOTTOM of the screen
 113                         speed_min[BOTTOM] = -dy1;
 114                         ti[BOTTOM] = -(dy0+dy1)/2;
 115                 } else {
 116                         // Rocks moving up and down
 117                         speed_max[TOP] = dy1;
 118                         ti[BOTTOM] = -dy0/2;
 119                         ti[TOP] = dy1/2;
 120                 }
 121         } else {
 122                 // Rocks moving down only. so the TOP of the screen
 123                 speed_min[TOP] = dy0;
 124                 speed_max[TOP] = dy1;
 125                 ti[TOP] = (dy0+dy1)/2;
 126         }
 127         ti[TOP] *= vfactor;
 128         ti[BOTTOM] *= vfactor;
 129 }
 130
 131 float
 132 weighted_rnd_range(float min, float max) {
 133         return sqrt(min * min + frnd() * (max * max - min * min));
 134 }
 135
 136 void
 137 new_rocks(void)
 138 {
 139         int i,j;
 140         float ti[4];
 141         float rmin[4];
 142         float rmax[4];
 143
 144         if(nrocks < F_ROCKS) {
 145                 nrocks_timer += t_frame;
 146                 if(nrocks_timer >= nrocks_inc_ticks) {
 147                         nrocks_timer -= nrocks_inc_ticks;
 148                         nrocks++;
 149                 }
 150         }
 151
 152         rock_sides(ti, rmin, rmax);
 153
 154         // loop through the four sides of the screen
 155         for(i=0; i<4; i++) {
 156                 // see if we generate a rock for this side this frame
 157                 rtimers[i] += ti[i]*t_frame;
 158                 while(rtimers[i] >= 1) {
 159                         rtimers[i] -= 1;
 160                         j=0;
 161                         while(rockptr->active && j<MAXROCKS) {
 162                                 if(++rockptr - rock >= MAXROCKS) rockptr = rock;
 163                                 j++;
 164                         }
 165                         if(!rockptr->active) {
 166                                 rockptr->type_number = random() % NROCKS;
 167                                 rockptr->image = surf_rock[rockptr->type_number];
 168                                 rockptr->shape = &rock_shapes[rockptr->type_number];
 169                                 switch(i) {
 170                                         case RIGHT:
 171                                                 rockptr->x = XSIZE;
 172                                                 rockptr->y = frnd()*(YSIZE + rockptr->image->h);
 173
 174                                                 rockptr->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 175                                                 rockptr->dy = RDY*crnd();
 176                                                 break;
 177                                         case LEFT:
 178                                                 rockptr->x = -rockptr->image->w;
 179                                                 rockptr->y = frnd()*(YSIZE + rockptr->image->h);
 180
 181                                                 rockptr->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
 182                                                 rockptr->dy = RDY*crnd();
 183                                                 break;
 184                                         case BOTTOM:
 185                                                 rockptr->x = frnd()*(XSIZE + rockptr->image->w);
 186                                                 rockptr->y = YSIZE;
 187
 188                                                 rockptr->dx = RDX*crnd();
 189                                                 rockptr->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 190                                                 break;
 191                                         case TOP:
 192                                                 rockptr->x = frnd()*(XSIZE + rockptr->image->w);
 193                                                 rockptr->y = -rockptr->image->h;
 194
 195                                                 rockptr->dx = RDX*crnd();
 196                                                 rockptr->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
 197                                                 break;
 198                                 }
 199
 200                                 rockptr->active = 1;
 201                         }
 202                 }
 203         }
 204 }
 205
 206 void
 207 move_rocks(void)
 208 {
 209         int i;
 210
 211         // Move all the rocks
 212         for(i = 0; i < MAXROCKS; i++) {
 213                 if(rock[i].active) {
 214                         // move
 215                         rock[i].x += (rock[i].dx-screendx)*t_frame;
 216                         rock[i].y += (rock[i].dy-screendy)*t_frame;
 217                         // clip
 218                         if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
 219                                         || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
 220                                 rock[i].active = 0;
 221                         }
 222                 }
 223         }
 224 }
 225
 226 void
 227 draw_rocks(void)
 228 {
 229         int i;
 230         SDL_Rect src, dest;
 231
 232         src.x = 0; src.y = 0;
 233
 234         for(i = 0; i<MAXROCKS; i++) {
 235                 if(rock[i].active) {
 236                         src.w = rock[i].image->w;
 237                         src.h = rock[i].image->h;
 238
 239                         dest.w = src.w;
 240                         dest.h = src.h;
 241                         dest.x = (int) rock[i].x;
 242                         dest.y = (int) rock[i].y;
 243
 244                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 245
 246                 }
 247         }
 248 }
 249
 250 int
 251 hit_rocks(float x, float y, struct shape *shape)
 252 {
 253         int i;
 254
 255         for(i=0; i<MAXROCKS; i++) {
 256                 if(rock[i].active) {
 257                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 258                                 return 1;
 259                 }
 260         }
 261         return 0;
 262 }
 263
 264 void
 265 blast_rocks(float x, float y, float radius, int onlyslow)
 266 {
 267         int i;
 268         float dx, dy, n;
 269
 270         if(onlyslow) return;
 271
 272         for(i = 0; i<MAXROCKS; i++ ) {
 273                 if(rock[i].x <= 0) continue;
 274
 275                 // This makes it so your explosion from dying magically doesn't leave
 276                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 277                 // only rocks that are barely moving will be pushed.
 278                 if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
 279
 280                 dx = rock[i].x - x;
 281                 dy = rock[i].y - y;
 282
 283                 n = sqrt(dx*dx + dy*dy);
 284                 if(n < radius) {
 285                         n *= 15;
 286                         rock[i].dx += 54.0*dx/n;
 287                         rock[i].dy += 54.0*dy/n;
 288                 }
 289         }
 290 }