Getting a pixels colour?

Hi there, I've been playing around with the BlitzMax demo, and I was wondering if there is any way to read pixel data from the back buffer, or any where else for that matter. The equivalent Blitz3D command would be GetColor or ReadPixel.

You can use ReadPixel (it must be used with a pixmap).

To read the backbuffer you have to use glReadPixels(). Standard OpenGL is unfortunately very poor with regards to reading the buffer, although quite competent at drawing it.

Here's an example of writepixel...
click

It's a bit long winded but next BlitzMax update will allow a more efficient method:

Function ReadBackBuffer(x,y)
	Global	grab
	Local	rgba,pixmap
	
	If Not grab grab=CreateImage(1,1,1,DYNAMICIMAGE)
	GrabImage grab,x,y
	pixmap=LockImage(grab,0,True,False)
	rgba=ReadPixel(pixmap,0,0)
	UnlockImage pixmap
	Return rgba
End Function

Thanks guys. I've got it sorted now.