Add common file with GLMAT_ARRAY_TYPE, GLMAT_EPSILON and GLMAT_RANDOM

[manuelcabral]

No description provided.

[mattdesl]

Thanks for the PR!

One of the difficulties with this is that it exposes these globals to the end-user, which could lead to some problems across many modules. For example, module A might rely on GLMAT_ARRAY_TYPE to be an Array (e.g. using [].map et al), whereas module B might rely on it being a typed array.

Not sure what the best approach is for this, maybe @hughsk and @mikolalysenko have some ideas.

[manuelcabral]

Thank you for the reply and the very useful module!

I'm not sure I understand the difficulty. Isn't this also an issue when using the original gl-matrix?

[mattdesl]

The problem becomes more pronounced in modular programming, where you have dozens of dependents on a module, and then dozens more transitive and unlisted dependents. These modules all need to work together; e.g.

• module A and B both rely on gl-mat4
• module C relies on A and B
• module D relies on module C

If either A or B changed the internal state of gl-mat4 it could have catastrophic effects across dozens of dependents.

This was never really a problem with the original vision of gl-matrix since most consumers of it are not working with a dependency depth greater than 1.

[manuelcabral]

I understand now. What if common.js exported functions which just return the values, not allowing them to be changed?