<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Slow performance using glDrawElementsBaseVertex" href="https://bugs.freedesktop.org/show_bug.cgi?id=105256#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Slow performance using glDrawElementsBaseVertex" href="https://bugs.freedesktop.org/show_bug.cgi?id=105256">bug 105256</a> from <a class="email" href="mailto:sroland@vmware.com" title="Roland Scheidegger <sroland@vmware.com>"> Roland Scheidegger</a> <pre>At a quick glance, I'd suspect the problem isn't really drawElementsBaseVertex per se, but the use of GL_UNSIGNED_BYTE indices as the code seemed to do. The hw doesn't support ubyte indices, and this has to be emulated by converting the elements to ushort (and if you don't start from zero, IIRC this can get huge buffers allocated especially if start is negative, but I don't remember the details). I don't know if the driver could do better, but in general you're advised to not use ubyte indices (this is a gl only feature, d3d doesn't support it, so it's unsurprising some hw doesn't support it natively). (Note that even early GCN does not support ubyte indices, they are only supported starting with Vulcanic Islands.)</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>