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akane
06-09-2009, 03:50 AM
Hi! I would like to know how to read and write directly to video memory.
Thank you very much :)

_NK47
06-09-2009, 04:27 AM
not precise enough. textures can be used to store data on video memory f.e. also vertex buffer objects. the first is "usually" used for images the later for vertices or indices but in fact you can store absolutely anything you want in texture objects or vertex buffer objects.

akane
06-11-2009, 08:47 AM
My problem is that I want to dump the contents of a window in another, but if the first window is outside of the field of vision of my PC monitor, when I show the contents in the second window, the area of the first window that is hidden becomes black in the second window. I attached a screenshot :
http://img13.imageshack.us/img13/7203/screenshotowa.jpg
Thank you.

P.D. : sorry for my english, Im spanish

ZbuffeR
06-11-2009, 09:16 AM
if the first window is outside of the field of vision of my PC monitor
As per the "pixel ownership test", if a pixel is not visible, it is undefined (so it can be anything, white, purple, black, correct, ...).
http://www.opengl.org/documentation/specs/version1.1/glspec1.1/node94.html
See also FAQ 14.070 :
http://www.opengl.org/resources/faq/technical/rasterization.htm

Use a FBO (framebuffer object) if you need solid offscreen rendering.
Tutorials :
http://www.gamedev.net/reference/programming/features/fbo1/
http://www.opengl.org/wiki/GL_EXT_framebuffer_object

akane
06-11-2009, 09:28 AM
Thank you very much!!! :)