progs/egl/openvg/trivial/readpixels.c

   1 #include "eglcommon.h"
   2
   3 #include <VG/openvg.h>
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <assert.h>
   9
  10 float red_color[4] = {1.0, 0.0, 0.0, 1.0};
  11 float blue_color[4] = {0.0, 0.0, 1.0, 1.0};
  12 VGint *data;
  13
  14 static void
  15 init(void)
  16 {
  17    data = malloc(sizeof(VGint)*2048*2048);
  18 }
  19
  20 /* new window size or exposure */
  21 static void
  22 reshape(int w, int h)
  23 {
  24    vgLoadIdentity();
  25 }
  26
  27 static void
  28 draw(void)
  29 {
  30    static const VGint red_pixel  = 255 << 24 | 255 << 16 | 0 << 8 |   0;
  31    static const VGint blue_pixel = 255 << 24 |   0 << 16 | 0 << 8 | 255;
  32    VGint i;
  33
  34    vgSetfv(VG_CLEAR_COLOR, 4, red_color);
  35    vgClear(0, 0, window_width(), window_height());
  36    vgFlush();
  37
  38    memset(data, 0, window_width() * window_height() * sizeof(VGint));
  39
  40    vgReadPixels(data, window_width() * sizeof(VGint),
  41                 VG_lARGB_8888,
  42                 0, 0, window_width(), window_height());
  43
  44    fprintf(stderr, "Red 0 = 0x%x and at 600 = 0x%x\n",
  45            data[0], data[600]);
  46    for (i = 0; i < window_width() * window_height(); ++i) {
  47       assert(data[i] == red_pixel);
  48    }
  49
  50    vgSetfv(VG_CLEAR_COLOR, 4, blue_color);
  51    vgClear(50, 50, 50, 50);
  52    vgFlush();
  53
  54    memset(data, 0, window_width() * window_height() * sizeof(VGint));
  55
  56    vgReadPixels(data, 50 * sizeof(VGint),
  57                 VG_lARGB_8888,
  58                 50, 50, 50, 50);
  59
  60    fprintf(stderr, "Blue 0 = 0x%x and at 100 = 0x%x\n",
  61            data[0], data[100]);
  62    for (i = 0; i < 50 * 50; ++i) {
  63       assert(data[i] == blue_pixel);
  64    }
  65 }
  66
  67
  68 int main(int argc, char **argv)
  69 {
  70    int ret = run(argc, argv, init, reshape,
  71                  draw, 0);
  72
  73    free(data);
  74    return ret;
  75 }