<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [llvmpipe] Line antialiasing looks different when GL_LINE_STIPPLE is enabled with pattern 0xffff" href="https://bugs.freedesktop.org/show_bug.cgi?id=94193#c3">Comment # 3</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [llvmpipe] Line antialiasing looks different when GL_LINE_STIPPLE is enabled with pattern 0xffff" href="https://bugs.freedesktop.org/show_bug.cgi?id=94193">bug 94193</a> from <a class="email" href="mailto:brianp@vmware.com" title="Brian Paul <brianp@vmware.com>"> Brian Paul</a> <pre>(In reply to Roland Scheidegger from <a href="show_bug.cgi?id=94193#c2">comment #2</a>) > So if I understand this right, there's really two issues here: > 1) smooth lines don't quite work when line stippling is enabled > 2) we don't optimize fake-enabled line stippling away > > As for 2), this is something the state tracker could do. I don't know if > that's worth it? I actually recently looked at that myself but disabling line stipple if the pattern is 0xffff would potentially violate a GL invariance rule. It would depend on the driver/GPU. The deal is GL allows stippled lines with pattern = 0xffff to hit different pixels than the same line drawn with stippling disabled. But with pattern = 0xffff you should be guaranteed to hit the same pixels as two complementary patterns such as 0xff00 and 0x00ff. In fact, GL allows quite a few "no-op" states (such as blend GL_ONE/GL_ZERO, glAlphaFunc(GL_ALWAYS), etc) which seem useless but are included for invariance purposes. I don't know if anyone would depend on this particular line stipple behaviour in practice though. > I think we generally only optimize for stupid gl state > settings like this if there's actually apps out there which really do these > stupid things. So, are there such real apps? Oh, yes! :) A CAD app I was working on a few months ago draws many lines with stippling enabled with pattern 0xffff. But I think it was just sloppiness and not invariance-driven.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>