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         int dead;  // has been blown out of the way
  16                    // to make room for a new ship appearing.
  17         SDL_Surface *image;
  18         struct shape *shape;
  19         int type_number;
  20 };
  21
  22 struct rock_struct rock[MAXROCKS], *rockptr = rock;
  23
  24 float rockrate,rockspeed;
  25
  26 SDL_Surface *surf_rock[NROCKS];
  27 struct shape rock_shapes[NROCKS];
  28
  29 int countdown = 0;
  30
  31 float rnd(void);
  32
  33 uint32_t area;
  34
  35 int
  36 init_rocks(void)
  37 {
  38         int i;
  39         char a[MAX_PATH_LEN];
  40         SDL_Surface *temp;
  41
  42         area = 0;
  43
  44         for(i = 0; i<NROCKS; i++) {
  45                 snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
  46                 NULLERROR(temp = IMG_Load(a));
  47                 NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
  48                 get_shape(surf_rock[i], &rock_shapes[i]);
  49         }
  50         return 0;
  51 }
  52
  53 void
  54 new_rocks(void)
  55 {
  56         if(--countdown <= 0 && (rnd()*100.0<(rockrate += 0.025))) {
  57                 // Possibly create a rock
  58                 rockptr++;
  59                 if(rockptr-rock >= MAXROCKS) {
  60                         rockptr = rock;
  61                 }
  62                 if(!rockptr->active) {
  63                         rockptr->dx = -(rockspeed)*(1 + rnd());
  64                         rockptr->dy = rnd()-0.5;
  65                         rockptr->type_number = random() % NROCKS;
  66                         rockptr->image = surf_rock[rockptr->type_number];
  67                         rockptr->shape = &rock_shapes[rockptr->type_number];
  68                         rockptr->x = (float)XSIZE;
  69                         rockptr->y = rnd()*(YSIZE + rockptr->image->h);
  70                         rockptr->active = 1;
  71                         area += rockptr->shape->area;
  72                 }
  73                 if(gamerate>0.1) {
  74                         countdown = (int)(ROCKRATE/gamerate);
  75                 } else {
  76                         countdown = 0;
  77                 }
  78         }
  79 }
  80
  81 void
  82 move_rocks(void)
  83 {
  84         int i;
  85
  86         // Move all the rocks
  87         for(i = 0; i < MAXROCKS; i++) {
  88                 if(rock[i].active) {
  89                         rock[i].x += rock[i].dx*gamerate;
  90                         rock[i].y += rock[i].dy*gamerate + yscroll;
  91                         if(rock[i].y > YSIZE || rock[i].y < -rock[i].image->h) {
  92                                 if(rock[i].dead) {
  93                                         area -= rock[i].shape->area;
  94                                         rock[i].dead = 0;
  95                                         rock[i].active = 0;
  96                                 } else {
  97                                         // wrap
  98                                         rock[i].y = (YSIZE - rock[i].image->h) - rock[i].y;
  99                                         rock[i].y += (rock[i].dy*gamerate + yscroll) * 1.01;
 100                                 }
 101                         }
 102                         if(rock[i].x < -rock[i].image->w || rock[i].x > XSIZE) {
 103                                 area -= rock[i].shape->area;
 104                                 rock[i].active = 0;
 105                                 rock[i].dead = 0;
 106                         }
 107                 }
 108         }
 109 }
 110
 111 void
 112 reset_rocks(void)
 113 {
 114         int i;
 115
 116         area = 0;
 117         for(i = 0; i<MAXROCKS; i++ ) {
 118                 rock[i].active = 0;
 119                 rock[i].dead = 0;
 120         }
 121
 122         rockrate = 54.0;
 123         rockspeed = 5.0;
 124 }
 125
 126 void
 127 draw_rocks(void)
 128 {
 129         int i;
 130         SDL_Rect src, dest;
 131
 132         src.x = 0; src.y = 0;
 133
 134         for(i = 0; i<MAXROCKS; i++) {
 135                 if(rock[i].active) {
 136                         src.w = rock[i].image->w;
 137                         src.h = rock[i].image->h;
 138
 139                         dest.w = src.w;
 140                         dest.h = src.h;
 141                         dest.x = (int) rock[i].x;
 142                         dest.y = (int) rock[i].y;
 143
 144                         SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
 145
 146                 }
 147         }
 148 }
 149
 150 int
 151 hit_rocks(float x, float y, struct shape *shape)
 152 {
 153         int i;
 154
 155         for(i=0; i<MAXROCKS; i++) {
 156                 if(rock[i].active) {
 157                         if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
 158                                 return 1;
 159                 }
 160         }
 161         return 0;
 162 }
 163
 164 void
 165 blast_rocks(float x, float y, float radius, int onlyslow)
 166 {
 167         int i;
 168         float dx, dy, n;
 169
 170         for(i = 0; i<MAXROCKS; i++ ) {
 171                 if(rock[i].x <= 0) continue;
 172
 173                 // This makes it so your explosion from dying magically doesn't leave
 174                 // any rocks that aren't moving much on the x axis. If onlyslow is set,
 175                 // only rocks that are barely moving will be pushed.
 176                 if(onlyslow && (!rock[i].dead || rock[i].dx < -4 || rock[i].dx > 3)) {
 177                         continue;
 178                 }
 179
 180                 dx = rock[i].x - x;
 181                 dy = rock[i].y - y;
 182
 183                 n = sqrt(dx*dx + dy*dy);
 184                 if(n < radius) {
 185                         n *= 20;
 186                         rock[i].dx += rockrate*(dx+30)/n;
 187                         rock[i].dy += rockrate*dy/n;
 188                         rock[i].dead = 1;
 189                 }
 190         }
 191 }