I read somewhere that recent GPU’s don’t support hardware accelerated GL_LINE strips, and it’s faster to just draw thin GL_QUAD’s.
Is this true?
Also, I need to apply AA to these lines, is AA any faster/slower on lines compared to thin quads?
It depends on what GPU you’re talking about. Workstation class hardware has traditionally been better at lines, as that’s a big deal with CAD/CAM. Although the latest offerings from Nvidia and Ati can surely crank out some serious lines, with full-scene AA no less.
You can count on lines being accelerated, but the speed and quality are going to vary from board to board. On consumer hardware, sometimes quads are better if you need thick lines with anti-aliasing, given that the spec only stipulates a minimum AA line with of 1.0. You can query this with glGetIntegerv and GL_LINE_WIDTH_RANGE/GL_LINE_WIDTH_GRANULARITY. As always, a careful measurement is the best way to determine relative performance.