Subject:
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Re: Type 5 lines, BFC relevance, and OpenGL
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Newsgroups:
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lugnet.cad.dev
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Date:
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Sun, 3 Apr 2005 22:31:09 GMT
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Viewed:
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2332 times
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So, I got the code updated so the conditional drawing happens in a display list,
and then built LDView with full optimizations turned on in the compiler, and the
new method actually runs slightly slower than the old method. (This is on an
ATI Radeon 9700 Pro.)
Of course, having a faster video card will speed up this new algorithm, while
having a faster CPU will speed up the old one. Incidentally, I tried it with
the new triangle geometry being drawn using vertex arrays, and the performance
plumetted. So, it’s faster with triangles inside glBegin/glEnd pairs than it is
with vertex arrays. The vertex array speed probablem only happens when edge
flags are enabled for the vertex array. (Of course, this is required in order
for the algorithm to work.) Obviously ATI didn’t optimize that path. I haven’t
yet tried either path on an nVidia card, so I don’t know how they would perform
there.
My code is set up so that the new functionality will get a preference, so the
end user will be able to see for themself which way is faster.
--Travis
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Message has 1 Reply:
 | | Re: Type 5 lines, BFC relevance, and OpenGL
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| Slower, you say? Are you executing the functions in immediate mode? Or using a display list? Because if you're not using a display list, it's no suprise that it's slower. If you are using a display list, however, then I'm at a loss. I guess it may (...) (20 years ago, 4-Apr-05, to lugnet.cad.dev)
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Message is in Reply To:
| | Re: Type 5 lines, BFC relevance, and OpenGL
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| (...) Well, I tried this in LDView, and it seems to work fine. I haven't yet put the new stuff in a display list, so it's drawing all the type 5 line geometry in immediate mode. Consequently, I'm not yet sure how fast it will be (it's very similar (...) (20 years ago, 1-Apr-05, to lugnet.cad.dev, FTX)
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