Invert Destination Color

BBrown · June 4, 2003, 3:22am

What is the best way to invert the destination pixel color when drawing. Is this possible?

knackered · June 4, 2003, 3:33am

Off hand,
glEnable(GL_BLEND);
glBlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ZERO);

Relic · June 4, 2003, 4:07am

Or
glLogicOp(GL_INVERT);
glEnable(GL_COLOR_LOGIC_OP);

BBrown · June 4, 2003, 4:22am

Thanks for the quick responses. I could have sworn I did the blend like that yesterday, but seems to work great now. The logical op works great too. Any idea if there is much of a speed difference?

harsman · June 4, 2003, 7:51am

LogicOp is probably much slower on most hardware.