Optimization: Better typing across the package

[VarLad]

Taking a look at the package code, it'd be nice if we can:

• Have proper types across multiple structs for better dispatch and compilation.
• Use StructArray for storing vector-of-structs (like scene.objects).

[arhik]

We already have a project tab here https://github.com/orgs/JuliaWGPU/projects/3

We can file an issue where type system needs work and complete it. Keeping this issue active anyways.

[arhik]

We can pick each example and fix typesystem for each example. This will help us understand the benefits of type stability. I have Tracy integration example which might help us document performance improvements or julia use new chainmarks.jl package.

For me Typesystem is a way towards static compiling purpose.

[VarLad]

@arhik Whats the purpose of this variable defined here?
https://github.com/JuliaWGPU/WGPUgfx.jl/blob/main/src/primitives/camera.jl#L15
I was wondering why didn't you use I instead of defining a coordinateTransform

I also can't find any instances of invCoordinateTransform being used 🤔

[arhik]

This is used to convert between conventions used in different frameworks like opengl, webgl, blender, etc ... We cannot use I since we exchange rows for different types of transformations. If any framework or data we load uses different convention then we can just exchange rows or flip sign using this matrix. Such matrices won't necessarily be identity matrices.

For example: if some framework uses (x, z, -y) as coordinate conventions instead of (x, y, z) we can simply exchange 2 and row of this matrix and also flip sign of y. Then when we multiply [a, b, c] data with this matrix it becomes [a, c, -b].

[arhik]

I think we can simply use inv function. They are unitary matrices so I remember calling inv should do inverse transformation. Will have to double check though.

[arhik]

Sorry I misread your comment. I didn't need inverse transform yet. But we will most likely. Its rather common in computer vision and graphics.

[arhik]

They are both like placeholders for now. I used it some of my own experiments like robotics simulator to load blender data.

[arhik]

Properly generalizing it will be good feature to add.