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OpenFrameworks audio visualization

December 26th, 2008


Passion Pit – Sleepyhead from eduardo omine on Vimeo.

After making some tests with Java OpenGL (JOGL) in Eclipse, I decided I should try OpenFrameworks again to delve deeper into OpenGL. The main problem with JOGL is that it’s a “layer” on top of the original OpenGL API; some things are different and often more complex in JOGL (for example the need to pass ByteBuffers instead of arrays).

This audio visualization is a simple exercise with FBOs, VBOs and shaders. An audio-reactive particle system (512 quads) is rendered to a FBO and applied as texture to a cube. This cube is then rendered to a second FBO, which is applied as texture to a second cube. There is a slight blur effect made with GLSL shaders. The stripes result from the way the cube was UV-mapped, an unexpected effect that turned out interesting.

At a 640×480 pixels resolution, framerate varies from 30 to 60 FPS in my computer, equipped with a GeForce 6200 (I need to upgrade my PC).

Happy 2009 to all! :-)

Tantalus Quest at FILE 2008

August 4th, 2008

Tantalus Quest is a game / installation that I developed at colmeia for FILE 2008, Brazil’s main electronic arts festival.

Game designer Fabiano Onça conceived the game, in which people must fill geometric shapes with their own silhouettes (as captured by webcams hanging from the ceiling):


Tantalus Quest at FILE 2008 from eduardo omine on Vimeo.

Software was built with OpenFrameworks, which is to C++ what Processing is to Java. A prototype was built with Flash (AS3), but it was slow — reading pixel values (BitmapData.getPixel) can be processor-heavy. Thanks to OpenFrameworks, porting the AS3 code to C++ was quite easy.

The application is very simple: the images captured by the cameras are brightened, blurred and thresholded, resulting in black blobs. The amount of blob pixels inside the geometric shape count as positive points and the pixels outside the geometric shape count as negative points.

This was my first project with computer art in a physical space — it’s something that I should explore further in my personal projects.

More pictures at Flickr.

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