git.mutantstargoat.com Git - glpixels/blob - sdlpixels.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <math.h>
   5 #include <SDL/SDL.h>
   6
   7 int init(void);
   8 void display(void);
   9
  10 int win_width, win_height;
  11 int max_xscroll, max_yscroll;
  12
  13 #define IMG_W   1400
  14 #define IMG_H   1200
  15 unsigned int img[IMG_W * IMG_H];
  16
  17 unsigned int start_tm;
  18 unsigned int num_frames;
  19
  20 int quit;
  21 SDL_Surface *fbsurf;
  22
  23
  24 int main(int argc, char **argv)
  25 {
  26         SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
  27         if(!(fbsurf = SDL_SetVideoMode(800, 600, 32, SDL_SWSURFACE))) {
  28                 fprintf(stderr, "failed to set video mode\n");
  29                 return 1;
  30         }
  31         SDL_WM_SetCaption("SDL pixel drawing benchmark", 0);
  32
  33         if(init() == -1) {
  34                 return 1;
  35         }
  36
  37         start_tm = SDL_GetTicks();
  38         while(!quit) {
  39                 SDL_Event ev;
  40                 while(SDL_PollEvent(&ev)) {
  41                         switch(ev.type) {
  42                         case SDL_QUIT:
  43                                 goto done;
  44
  45                         case SDL_KEYDOWN:
  46                                 if(ev.key.keysym.sym == 27) goto done;
  47                                 break;
  48
  49                         default:
  50                                 break;
  51                         }
  52                         if(quit) goto done;
  53                 }
  54
  55                 display();
  56         }
  57
  58 done:
  59         SDL_Quit();
  60         return 0;
  61 }
  62
  63
  64 int init(void)
  65 {
  66         int i, j, xor, r, g, b;
  67         unsigned int *ptr;
  68
  69         ptr = img;
  70         for(i=0; i<IMG_H; i++) {
  71                 for(j=0; j<IMG_W; j++) {
  72                         xor = i ^ j;
  73                         r = (xor >> 1) & 0xff;
  74                         g = xor & 0xff;
  75                         b = (xor << 1) & 0xff;
  76                         *ptr++ = b | (g << 8) | (r << 16);
  77                 }
  78         }
  79
  80         win_width = 800;
  81         win_height = 600;
  82
  83         max_xscroll = IMG_W - win_width;
  84         max_yscroll = IMG_H - win_height;
  85         return 0;
  86 }
  87
  88 void display(void)
  89 {
  90         int i, j;
  91         unsigned int tm = SDL_GetTicks() - start_tm;
  92         unsigned int interv;
  93         float t = tm / 256.0f;
  94         int xoffs = (int)((sin(t) * 0.5f + 0.5f) * max_xscroll);
  95         int yoffs = (int)((cos(t) * 0.5f + 0.5f) * max_yscroll);
  96         unsigned int *start = img + yoffs * IMG_W + xoffs;
  97         unsigned int *dest;
  98
  99         if(SDL_MUSTLOCK(fbsurf)) {
 100                 SDL_LockSurface(fbsurf);
 101         }
 102         dest = fbsurf->pixels;
 103
 104         for(i=0; i<win_height; i++) {
 105                 for(j=0; j<win_width; j++) {
 106                         *dest++ = start[j];
 107                 }
 108                 start += IMG_W;
 109         }
 110
 111         if(SDL_MUSTLOCK(fbsurf)) {
 112                 SDL_UnlockSurface(fbsurf);
 113         }
 114         SDL_Flip(fbsurf);
 115
 116         num_frames++;
 117         tm = SDL_GetTicks();
 118         interv = tm - start_tm;
 119         if(interv >= 4000) {
 120                 unsigned int fps = 100000 * num_frames / interv;
 121                 printf("SDL: %.2f fps\n", fps / 100.0f);
 122                 num_frames = 0;
 123                 start_tm = tm;
 124                 quit = 1;
 125         }
 126 }