SSAO on consoles (milisecond cost at 720p and below?)

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4 comments, last by David Neubelt 14 years, 6 months ago
Just curious if there are any tech white papers on SSAO and consoles. Just curious what the usual millisecond cost is (if it's mostly fixed cost, or if it varies a lot, etc), assuming a framebuffer of 720p max. I've heard speculation on various games that shipped with SSAO, but wasn't sure if there was any official tech talks. Thanks! :)
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if youre achieving less than 10msec then be happy
Depending on your implementation, the cost of ssao can vary dramatically. For example, due to varying sampling area (when projecting area onto 2d), if you get very close to objects you can expect some pretty major spikes. There's some workarounds and a lot of trickery, but I'd recommend reading up on Starcraft II's approach.
Running the algorithm at 720p resolution is also a pretty terrible idea since AO is a low-frequency phenomenon, so ideally you'd use down-sampled buffers.
Also, 10ms is a pretty terrible figure, since that would be 1/3 of your frame if targeting 30fps ;-)
>>Also, 10ms is a pretty terrible figure, since that would be 1/3 of your frame if targeting 30fps ;-)

10msec @720p its pretty good, see nvidia etc examples for what they achieve on more powerful hardware

though youre right
you will most likely want to run at smaller resolution
perhaps u dont need the normal values for edge detection
use less examples
Sorry, I should have clarified my assumptions.

I certainly wouldn't think a developer would use a full-res SSAO solution, as it would be a waste on current hardware.

Thanks for the responses. :)
Quote:Original post by zedz
>>Also, 10ms is a pretty terrible figure, since that would be 1/3 of your frame if targeting 30fps ;-)

10msec @720p its pretty good, see nvidia etc examples for what they achieve on more powerful hardware

though youre right
you will most likely want to run at smaller resolution
perhaps u dont need the normal values for edge detection
use less examples


If your on PS3 you can do a SPU version and get it under 5ms.
Graphics Programmer - Ready At Dawn Studios

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