git.mutantstargoat.com Git - laserbrain_demo/blob - src/post.cc

   1 #include "opengl.h"
   2 #include "app.h"
   3
   4 static void update_fbtex();
   5
   6 static unsigned int fb_tex;
   7 static int fb_tex_width, fb_tex_height;
   8
   9 void slow_post(unsigned int sdr)
  10 {
  11         update_fbtex();
  12
  13         glBindTexture(GL_TEXTURE_2D, fb_tex);
  14         glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, win_width, win_height);
  15
  16         glPushAttrib(GL_ENABLE_BIT);
  17         glDisable(GL_DEPTH_TEST);
  18         glDisable(GL_LIGHTING);
  19
  20         glUseProgram(sdr);
  21
  22         float umax = (float)win_width / (float)fb_tex_width;
  23         float vmax = (float)win_height / (float)fb_tex_height;
  24
  25         glBegin(GL_QUADS);
  26         glTexCoord2f(0, 0);
  27         glVertex2f(-1, -1);
  28         glTexCoord2f(umax, 0);
  29         glVertex2f(1, -1);
  30         glTexCoord2f(umax, vmax);
  31         glVertex2f(1, 1);
  32         glTexCoord2f(0, vmax);
  33         glVertex2f(-1, 1);
  34         glEnd();
  35
  36         glPopAttrib();
  37 }
  38
  39 static int next_pow2(int x)
  40 {
  41         x--;
  42         x = (x >> 1) | x;
  43         x = (x >> 2) | x;
  44         x = (x >> 4) | x;
  45         x = (x >> 8) | x;
  46         x = (x >> 16) | x;
  47         return x + 1;
  48 }
  49
  50 static void update_fbtex()
  51 {
  52         if(win_width <= fb_tex_width && win_height <= fb_tex_height) {
  53                 return;         // nothing to do
  54         }
  55         if(!fb_tex) {
  56                 glGenTextures(1, &fb_tex);
  57                 glBindTexture(GL_TEXTURE_2D, fb_tex);
  58                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  59                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  60         } else {
  61                 glBindTexture(GL_TEXTURE_2D, fb_tex);
  62         }
  63
  64         fb_tex_width = next_pow2(win_width);
  65         fb_tex_height = next_pow2(win_height);
  66         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fb_tex_width, fb_tex_height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
  67 }