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Index › Programming Questions & Help › OpenGL and 3D Libraries › 3D Calculations without the 3D Renderer
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3D Calculations without the 3D Renderer (Read 958 times)
phrontist
3D Calculations without the 3D Renderer
Mar 26th, 2010, 9:28am  
The processing idiom for doing this eludes me: I want to create several 3d points (i.e. vectors), rotate them about arbitrary axes, scale them, and then get their X, Y, and Z coordinates (using an orthographic projection). I still want to use P2D as my renderer, I just need to do some 3D calculations.

PVectors seemed like the obvious way to go, but I couldn't find a way to rotate them about an arbitrary axes. screenX and the like seemed helpful, but again require P3D as renderer. I guess I could create a seperate PGraphics instance using P3D to get the points, but this seems like a hack. I could also write my own class to do this, but this must be built in to the language somehow...
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davbol
Re: 3D Calculations without the 3D Renderer
Reply #1 - Mar 26th, 2010, 2:58pm  
For purposes here, vectors don't "perform transforms", they just "get transformed".  So you need a matrix to define and perform the transform (and yes, there's an arbitrary axis rotate) f.e.:
PMatrix3D m = new PMatrix3D();
m.rotate(angle,x,y,z);
m.mult(yourSourceVector, yourTargetVector);
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