Radial Vertex Displacement Mapping

Thanks to some great work (and a fortuitous accident) from the good people at Kineme.net, it’s now possible to use moving images as Displacement Maps in a GLSL Vertex Shader in QC. So I thought I’d give it a go.

Radial VDM 01Radial VDM 02Radial VDM 04Radial VDM 03

The input is the iSight camera, with luminosity modulating the Radius parameter of a function to bend a GLSL grid into a sphere, so what we have is essentially a radial distortion of a sphere, based on the luminosity of the input texture.

This is very cool, and something I’ve been wanting to do for ages. It opens the doors to all sorts of mesh-related fun, as you can potentially use custom CIFilter or GLSL Fragment shader code to create different displacement images to feed into the patch.

The only problem is, it runs quite slowly on my machine. It’s undoubtedly much faster to do this kind of thing with Vertex Buffer objects, but that means custom OpenGL code in a QC plugin, which is way beyond my capabilities currently. Sadly.


3 Responses to “Radial Vertex Displacement Mapping”

  1. March 26, 2008 at 6:45 pm

    Have you tried it with the blur filters yet? It creates such nice smooth shapes… too bad it’s so slow (as you’ve mentioned).

    As always, your pictures are inspiring to those of us that paint in zeros in ones 😉

  2. 2 toneburst
    March 26, 2008 at 6:55 pm


    thanks for the great feedback! It’s binary painting that inspires (and enables) it all though 😉

    I can get a similar effect to applying a blur just be reducing the dimensions of the Displacement Map texture. I’ve setup a Multiplexer with an Index splitter so I can set the DM to 16, 32, 64, 128, 256 or 512 pixels, via a Resize patch. Using lower values seems to smooth things out quite nicely, and with the added bonus of marginally increasing the framerate. The bottom two screenshots used a DM of (I think) 32×32 pixels. Using an actual blur would probably make for smooother results, but I try to avoid blurs if at all possible, because they zap the framerate like nothing else…


  3. 3 iureart_visuals
    September 23, 2008 at 8:07 pm

    can we make this stuff with qtz from macos 10.4…

    can you release some more informations about this creations for people who are just trying to understand qtz composer!? or send me some links with tutorials about this…i’m working with qtz about more and less one year, but it’s dificult because you speak in things that i never have listen before and it mess with my brain…thanks

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