I think there is a bug in jit.mxform2d when instantiated inside jit.expr, when "c" mxform parameter is negative. See attached patch. Tested in Max 6 & 7.
Thanks for letting me know if the error is in the patch.
It looks like this instant crash feature has to do not only with the mentioned params being negative, but also with the interp attribute: the following patch gives you an instant crash only with interp 1:
I mentioned a bug with mxform2d in jit.expr in 2007: https://cycling74.com/forums/bug-in-jit-expr-with-functor-jit-mxform2d/
The post text disappeared, but here is the patch I sent at the time. I don't have the original steps to reproduce, but you'll see the bug if you do the following:
- create a new empty patch (Max 4.6, 5, 6 or 7)
- paste the patch below
- double-click the [loadbang] object
- click the "chilis.jpg" message box
- click the [button] to output the matrix
- see, the image is the same on left & right
- now, set the "u" value to -0.1 (negative value)
- hit the [button] again
- see, image on the right is correct, nothing shows up on the left, when jit.mxform2d is instantiated by jit.expr.
- plus you may get a crash after all: not immediately, but when you close the patch (Max 6 or 7)