Non-uniform scaling

[ned flanders]

Hi, noob question, wondering if there's an easy way to do non-uniform scaling, ie, where x,y,z, scaling factors are different.

My immediate need is simply to create a Primitive.Plane, which is of unit size, then scale as needed in the x,y directions.  For example, maybe I'd like a plane twice as wide as high.

Wait...just occurred to me...should I use the rotation matrix, and pass in values on the diagonal?

[ned flanders]

Well, I got it to work with the following code, in which I need not only non-uniform x-y scaling, but rotation baked in as well:

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plane = Primitives.getPlane(1,1);

Matrix scalingMat = new Matrix();
scalingMat.set(0, 0, width);
scalingMat.set(1, 1, height);

Matrix rotMat = plane.getRotationMatrix();
rotMat.rotateX((float)(Math.PI/2f));

scalingMat.matMul(rotMat);

plane.setRotationMatrix(scalingMat);


Let me know if there's an easier/better way for this.

[EgonOlsen]

That's ok, but it might screw up your normals so that lighting can become strange. You might want to add

Code Select Expand


plane.rotateMesh();
plane.clearRotation();


at the end to make the change permanent to the mesh.

[ned flanders]

Thanks, makes perfect sense, I forgot about the normals.