Wednesday, January 11, 2017

OpenCL path tracing tutorial 3: OpenGL viewport, interactive camera and defocus blur

Just a link to the source code on Github for now, I'll update this post with a more detailed description when I find a bit more time:



 Part 1 Setting up an OpenGL window

https://github.com/straaljager/OpenCL-path-tracing-tutorial-3-Part-1




Part 2 Adding an interactive camera, depth of field and progressive rendering

https://github.com/straaljager/OpenCL-path-tracing-tutorial-3-Part-2



Thanks to Erich Loftis and Brandon Miles for useful tips on improving the generation of random numbers in OpenCL to avoid the distracting artefacts (showing up as a sawtooth pattern) when using defocus blur (still not perfect but much better than before).

The next tutorial will cover rendering of triangles and triangle meshes.
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4 comments:

  1. UnknownJanuary 11, 2017 at 10:16 PM

    Thanks Sam! Can't wait to try this out on my machine! Thanks for the mention in your post. I am glad to contribute in some small way. Looking forward to the accompanying write-up for this post. Thanks again for all your hard work!
    -Erich

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  2. Jan VlietinckFebruary 5, 2017 at 10:45 PM

    Interesting but I'm more interested in volume rendering path tracing.

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  3. DaveApril 5, 2017 at 6:52 AM

    When I run this on nVidia GTX 660 I get some noticeably lighter pixels, they form a grid pattern within the resultant image. Any idea how to get past that?

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  4. Sam LapereApril 5, 2017 at 1:48 PM

    @ Jan Vlietinck: long time no see! How are things? Path tracing for medical volume rendering is something I want to look into quite soon-ish, Siemens "cinematic rendering" (https://www.youtube.com/watch?v=703Zzl8YYJk) produces stunning images

    Dave: The pattern is caused by a poor random number generator. Some people have contributed code improvements to make the RNG more "random" and less prone to artefacts, but it's still not as good as CUDA's quasi-random Sobol RNG.

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