Front to Back

OpenGL OpenGL: Basic Coding
1

Hi guys. I’m a newbie with opengl and would like to know a way to copy my Front Buffer to the Back Buffer. Is it possible? or I can swap only from back to front?

Thank you!

2

take a look at

glDrawBuffer
glReadBuffer
glCopyPixels

3

Thank yoy Mazy.

But how I DO I use glCopyPixels? I’ve been trying to make it work the entire day, but til now, nothing…

Look how I’m doing:

glReadBuffer(GL_FRONT);
glDrawBufer(GL_BACK);
glRasterPos3f(0.0f, 0.0f, 0.0f);
glCopyPixels(10, 10, 50, 50, GL_DEPTH);
glCopyPixels(10, 10, 50, 50, GL_COLOR);
glDrawBufer(GL_BACK);
glReadBuffer(GL_BACK);

I don’t know why… but it don’t work!!

Help me please!

Thank you
Fernando.

[This message has been edited by Fernando (edited 12-18-2002).]

4

Make sure the raster position is actually where you want it. Draw a single point at the raster position and see if it appears where you want it. If it doesn’t, maybe the raster position is outside the window, which makes it invalid.

5

Yeah!!!

I was giving the a wrong value for the Z axis.

Now I’m using glRasterPos3f(0.0f, 0.0f, -1.0f) and there’s a black box appearing on the center of the screen isntead of the front buffer…

Do you have any hints?

Thank you
fernando

6

All I can say right now is that something is wrong, but that’s obvious. You have to provide more information, preferably code (only relevant pieces).