Huge Viewport

I got a problem with making very big viewport (about 4096 x 4096). I want to set such viewport (some part will be invisible because I have smaller resolution (1024 x 768)) and I want to render something there and copy it (all channels RGBA) to an array of unsigned bytes. And I have one more question: I have for example, a box with a RGBA texture and I’m trying to render it, but I don’t want blending effect (I want just to put on screen this values RGBA (I can’t recognize A value - it’s invisible)) and when I ReadPixels the A valus is always 255. Do You have any idea?
Thanks for help


For the first question, you have to render your picture in small tiles that fit into your window. Go to , I think there’s a demo there on this.

And the second one, if all your alpha values are all 255, changes are you don’t have an alpha buffer. Make sure you’re running in 32 bit color mode. You may also have to request the alpha buffer when creating a window, in win32 you do that by setting cAlphaBits=8 in your pixel format descriptor. The other systems (mesa, glut…) I don’t know about.


Edit: Link didn’t work. Sigh…

[This message has been edited by JustHanging (edited 02-06-2003).]