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

   1 #include "opengl.h"
   2 #include "app.h"
   3 #include "texture.h"    // next_pow2
   4
   5 static void update_fbtex();
   6
   7 static unsigned int fb_tex;
   8 static int fb_tex_width, fb_tex_height;
   9
  10 void slow_post(unsigned int sdr)
  11 {
  12         update_fbtex();
  13
  14         glBindTexture(GL_TEXTURE_2D, fb_tex);
  15         glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, win_width, win_height);
  16
  17         glPushAttrib(GL_ENABLE_BIT);
  18         glDisable(GL_DEPTH_TEST);
  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 void update_fbtex()
  40 {
  41         if(win_width <= fb_tex_width && win_height <= fb_tex_height) {
  42                 return;         // nothing to do
  43         }
  44         if(!fb_tex) {
  45                 glGenTextures(1, &fb_tex);
  46                 glBindTexture(GL_TEXTURE_2D, fb_tex);
  47                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  48                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  49         } else {
  50                 glBindTexture(GL_TEXTURE_2D, fb_tex);
  51         }
  52
  53         fb_tex_width = next_pow2(win_width);
  54         fb_tex_height = next_pow2(win_height);
  55         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fb_tex_width, fb_tex_height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
  56 }