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Masking hit

Started by PmanC Jul 27, 2002 at 8:03 PM 2 replies 400+ views

Original Post

Jul 27, 2002 at 8:03 PM

hello... I just finished a program that uses 3 masked objects, and the framerate is very low(15-20). is there a way i can speed up masking? i don''t want to use the alfa channel because i want the program to work on every computer. -PmanC

Wavarian

Jul 27, 2002 at 11:51 PM

??! um.. alpha testing is supported by nearly every video card i can think up.. are you thinking of something else?

llvllatrix

Jul 28, 2002 at 11:59 PM

Try disable vsync on ur card. Im not sure, but it may be possible to do masking with multitexturing, that is changing blend functions when you bind the different textures. Havn''t tried it yet though...

RipTorn

Jul 29, 2002 at 12:56 AM

v-sync will have no effect.
as I''ve said before, masking is the poor mans alpha testing. Simply load a 4 channel image, and set the appropriate mask. You don''t need to be using blending to use alpha testing.

glEnable(GL_ALPHA_TEST);

glAlphaFunk(GL_NOTEQUAL,0);

or whatnot.
as far as I can tell, the hit that alpha test has is next to nothing. so it''s a good idea to use it all the time, and any textures that are blended (eg additive) should have black areas set to 0 alpha, etc. This will save fill rate.

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