Hi evrybody,
I’m puzzled by this: why when I draw a single pixel using Drawpixels on position x,y and read it back right after that I don’t get the updated pixel data?
here’s my code:
first thing that pops into my head is checking glReadBuffer().
In general using DrawPixels/ReadPixels is a bad idea. I used those but as soon as i tried my app on an Intel onboard chip it was soooooooooooo slow! use better textures instead?
still try checking those params at glReadBuffer though they are BACK by default.
If I am not mistaken, coordinates passed to glRasterPos are considered “object coordinates” thus treated like vertices coordinates set by glVertex. They are transformed by the modelview and projection matrices, then clipped and transformed to window coordinates.
I think you want to set window coordinates directly since glReadPixels takes window coordinates, so use glWindowPos instead of glRasterPos