Hmm ok, good to keep in mind. In that particular routine I do a clearscreen at the start, then I draw a bunch of objects, then I do a copypixels, so there is no flipping going on until everything is drawn.
I also made a new routine last night which seems to look different on the imac than on the ibook as well. I am wondering if there is maybe some command that I haven't called which is automatically initialized on the ibook but not on the imac. ... on the ibook it simply draws some GL_QUADS with texturing of a texture that I uploaded myself. It also does a readpixels from the RED component of the display, and then a writepixels of that same data to the stencil buffer. Then all I try to do is draw a filled untextured quad with blending on and the stencil test enabled. It looks right on the ibook but on the imac it comes out with strange white squares with what looks like some strange residual background showing up. Both systems have 8-bit stencil buffers and all the rest, so I don't know why it comes out differently.
I also made a new routine last night which seems to look different on the imac than on the ibook as well. I am wondering if there is maybe some command that I haven't called which is automatically initialized on the ibook but not on the imac. ... on the ibook it simply draws some GL_QUADS with texturing of a texture that I uploaded myself. It also does a readpixels from the RED component of the display, and then a writepixels of that same data to the stencil buffer. Then all I try to do is draw a filled untextured quad with blending on and the stencil test enabled. It looks right on the ibook but on the imac it comes out with strange white squares with what looks like some strange residual background showing up. Both systems have 8-bit stencil buffers and all the rest, so I don't know why it comes out differently.