> Neither the i830 nor 965gm actually support GL_CLAMP natively (yay for > d3d-only hardware). The different appearance is caused by the 965 driver > mapping GL_CLAMP to GL_CLAMP_TO_BORDER while the i830 maps it to > GL_CLAMP_TO_EDGE. The 965 driver has a comment saying that glconform > prefers GL_CLAMP_TO_BORDER, while the i830 has a comment saying that the > Windows GL driver uses GL_CLAMP_TO_EDGE. > > Several other drivers (savage, sis, unichrome) map GL_CLAMP to > GL_CLAMP_TO_EDGE. > > What should I do now? > > 1) Fix the 965 driver to make GL_CLAMP work correctly (icky, and will > be slower). > 2) Use GL_CLAMP_TO_EDGE in the 965 driver. > 3) Use GL_CLAMP_TO_BORDER in the i830 driver. > 4) Nothing.
If feasible, I'd make it configurable via a .drirc option whether to map to GL_CLAMP_TO_EDGE or to GL_CLAMP_TO_BORDER, and make the former the default. This change should be made in both 965 and i830, and ideally in all the other drivers where the hardware natively supports both GL_CLAMP_TO_EDGE and GL_CLAMP_TO_BORDER but not GL_CLAMP. Cursory Googling suggests that it's very common for other OpenGL implementations to map GL_CLAMP to GL_CLAMP_TO_EDGE (even if that's less conformant), and that consequently there're likely quite a few other OpenGL applications floating around in the wild that use GL_CLAMP when they mean GL_CLAMP_TO_EDGE. Implementing GL_CLAMP via software fallback (that's what you mean by "icky", right?) is probably overkill. --AWJ-- _________________________________________________________________ Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! http://spaces.live.com/spacesapi.aspx?wx_action=create&wx_url=/friends.aspx&mkt=en-us ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
