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Comment by simonsquiff | Hacker News Reader

If you have an iPad I highly recommend getting LiquidSketch. It's a great puzzler about getting pools of liquid into the right place, and the liquid effect is stunning. It moves exactly as expected, has surface tension, splits and recombines etc - but the really stunning element is colour mixing. When two groups of different colours combine the mixing of them is just utter convincing, and beautiful. Amazing how this was all done on a lowly iPad.

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http://www.liquidsketch.com/

There's a demo here:

http://www.youtube.com/watch?v=dpNjEEtodtg

When you say "on a lowly iPad", bear in mind that the latest (4th-gen) iPad has a dual core 1.4 GHz chip plus a GPU capable of 14.4 GFLOPs. It's actually a pretty powerful machine.

You still cannot compare it with the GPU from the OP rendering, that does 3000 GFLOPS (GTX 680).

I can however compare it to the famous Cray 2 supercomputer, capable of 1.9GFLOPS.

Remember when we were promised we'd someday have supercomputers in our pockets? We do.

Well, ok, fairly big pockets in the case of the iPad, but still, you get my point.

We also were promised real-time raytracing if we ever got to that point. What's the hold-up?

The number of rays needed to realistically model raytraced objects turned to be much higher than we ever expected, as far as I know.

The expected display resolution probably changed too.

Real-time raytracing is easy, if you can live with one or maybe two bounces.

Alternately, do lots of bounces with fewer rays, decrease the total dynamic range, and add a consistent noise/grain filter. Realistic raytraced night-vision :)

Real time raytracing is vary doable and high quality, it's just we got really good at rasterisation. Consider a 2012 demo http://www.youtube.com/watch?v=h5mRRElXy-w it's cool and all but what seperates it from rasterisation is fairly subtle and the computing costs are rather high.

Thanks for sharing this. I'm actually really excited; raytraced scenes have a "solid" feel to them that rasterized ones simply can't get.

You can totally do real-time raytracing. I wrote my first raytracer a couple of weeks ago — http://canonical.org/~kragen/sw/aspmisc/my-very-first-raytra... — and it gets about 4fps on simple scenes on my netbook, despite being the product of only a few hours of work. If you use a GPU and/or SSE and/or a faster CPU, you should easily hit full-motion video.

My netbook is probably half the speed of an iPad.

It would be fun to put together a custom OS-less AMI to raytrace partial frames in realtime on EC2. 20 instances spun up in a few hundred milliseconds could do pretty substantial real-time raytracing.

The CPU pulls tens of GFLOPs in single precision, too (and > 5 GFLOPs double precision!) It’s at least as powerful as any desktop you are likely to have had a decade ago.

What a charming little game. Just watching the video was strangely relaxing.

Now I finally wish I had an iPad. Waiting on the mini retina...I guess

I had the same concern, but after having a mini for a while, I can tell you that I don't notice the lack of retina resolution at all. They hold their value really well too - I highly recommend just getting one now and selling it once retina comes out.

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