do gamma correction on post if we don't have an sRGB framebuffer

[laserbrain_demo] / src / post.cc

diff --git a/src/post.cc b/src/post.cc
new file mode 100644 (file)
index 0000000..b675f5b
--- /dev/null
+++ b/src/post.cc
@@ -0,0 +1,67 @@
+#include "opengl.h"
+#include "app.h"
+
+static void update_fbtex();
+
+static unsigned int fb_tex;
+static int fb_tex_width, fb_tex_height;
+
+void slow_post(unsigned int sdr)
+{
+       update_fbtex();
+
+       glBindTexture(GL_TEXTURE_2D, fb_tex);
+       glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, win_width, win_height);
+
+       glPushAttrib(GL_ENABLE_BIT);
+       glDisable(GL_DEPTH_TEST);
+       glDisable(GL_LIGHTING);
+
+       glUseProgram(sdr);
+
+       float umax = (float)win_width / (float)fb_tex_width;
+       float vmax = (float)win_height / (float)fb_tex_height;
+
+       glBegin(GL_QUADS);
+       glTexCoord2f(0, 0);
+       glVertex2f(-1, -1);
+       glTexCoord2f(umax, 0);
+       glVertex2f(1, -1);
+       glTexCoord2f(umax, vmax);
+       glVertex2f(1, 1);
+       glTexCoord2f(0, vmax);
+       glVertex2f(-1, 1);
+       glEnd();
+
+       glPopAttrib();
+}
+
+static int next_pow2(int x)
+{
+       x--;
+       x = (x >> 1) | x;
+       x = (x >> 2) | x;
+       x = (x >> 4) | x;
+       x = (x >> 8) | x;
+       x = (x >> 16) | x;
+       return x + 1;
+}
+
+static void update_fbtex()
+{
+       if(win_width <= fb_tex_width && win_height <= fb_tex_height) {
+               return;         // nothing to do
+       }
+       if(!fb_tex) {
+               glGenTextures(1, &fb_tex);
+               glBindTexture(GL_TEXTURE_2D, fb_tex);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+       } else {
+               glBindTexture(GL_TEXTURE_2D, fb_tex);
+       }
+
+       fb_tex_width = next_pow2(win_width);
+       fb_tex_height = next_pow2(win_height);
+       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fb_tex_width, fb_tex_height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
+}