Question

i would like to aplly a reverse transformation matrix in a point.
What is it for?:
My app (game) apply transformation into several squares objects, each one has its own transformation matrix that are applyied when drawing it.

But i need to know if the mouse are over each object. so , for each object, I get the mouse position, and try to apply all transformations reversed. to revert the square and the mouseposition to its origin.

If im right, this way i can compare the transformed mouse position with the object bouds.

thw question is.. :how can i apply this reverse transformations ?
i tried the inverse matrix, but it dosent exists all the time…

Answer 1

If there is no inverse for a transformation matrix (highly unlikely for most common transformations), then there is no way to undo the transformation. That’s what having no inverse means: that the transformation is one-way.

Also, the way this is generally done is not by transforming mouse coordinates into world-space, but by transforming objects (or bounding-boxes thereof) into window space.