Add `wgpu` graphics server

[mrDIMAS]

Fyrox now supports custom graphics servers, which essentially is a tiny abstraction layer from graphics API. Currently there's only one graphics server, based on OpenGL 3.3/OpenGL ES 3.0. wgpu looks like a very good cross-platform replacement for OpenGL and it is definitely worth implementing a graphics server with it.

[Muktarsadiq]

Hi! I'd like to work on implementing the wgpu graphics server. This seems like a great fit since you've already built the abstraction layer for this purpose.

Before I start, could you help me with a few things?

1. Where can I find the GraphicsServer trait/interface? I want to study the OpenGL implementation as a reference.

2. What's the minimum feature set for an initial PR? I'm thinking: basic rendering → textures/lighting → advanced features. Does an incremental approach work, or would you prefer one comprehensive PR?

3. Any known gotchas with the abstraction that might be tricky when mapping to wgpu's API?

4. Shader handling: Will I need to port shaders from GLSL to WGSL, or is there an abstraction?

[b-guild]

Where can I find the GraphicsServer trait/interface?

Fyrox/fyrox-graphics/src/server.rs

Line 103 in 6021ae8

pub trait GraphicsServer: GraphicsServerAsAny {

[nice0hack]

Since no one has yet submitted a PR for wgpu integration, I'll continue the issue. The integration itself is very complex due to fundamental differences between OpenGL and wgpu concepts.

There's already a PR where you can run the engine on a raw wgpu implementation: #927

The implementation is raw, but the wgpu engine is ready for a first look.

This issue definitely needs to be addressed by the entire Fyrox Engine community, and the engine should gradually be fully migrated to wgpu. My tests show that wgpu is indeed a good replacement for OpenGL.