1
\$\begingroup\$

The page at https://webglfundamentals.org/webgl/lessons/webgl-2d-matrices.html provides an example for rotating around the center of the image:

// make a matrix that will move the origin of the 'F' to its center. var moveOriginMatrix = m3.translation(-50, -75);

Similarly, the library I'm using (gl-matrix), provides an ability to rotate around an origin vector:

fromRotationTranslationScaleOrigin [...] Creates a matrix from a quaternion rotation, vector translation and vector scale, rotating and scaling around the given origin

However, I'd like to generically set a rotation vector based on the relative local transform - e.g. something like giving [0.5,0.5, 0] as the origin parameter to fromRotationTranslationScaleOrigin() and have it always rotate around the center.

Would this require handling it somewhere else in the pipeline? (e.g. after composing with the perspective matrix) - or are there some best-practices ways of handling this?

I'd also like a matrix to allow centering within another's world matrix but that's a different question I guess :)

\$\endgroup\$

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.