Model Matrix: Rotations

As a follow-up to my article on Model Matrices, which describes the connection to change-of-coordinates matrices, I’ve found the time to revisit the topic. I’ve written a new article about matrix composition in the context of the Model and Rotation matrices to highlight the algebraic foundations.

In the article, I explore the difference between rotating an object around its own center (local space) and rotating it around an external point in the game world (world space). I show why the order of matrix multiplication is so important and how you can significantly improve performance by pre-calculating the transformation matrix. And since I use glm as a reference for my own implementation, I also cover how rotations are handled in that library (and in Unity).

You can read the article here.