Dependency between render and wgpu?

[entropylost]

For some reason, if I enable the render plugin, I also must have the wgpu plugin enabled.

For example,

[package]
name = "bevy-test"
version = "0.1.0"
edition = "2018"
[dependencies]
[dependencies.bevy]
version = "^0.2.1"
# git = "https://github.com/bevyengine/bevy"
default-features = false
features = [
    "bevy_audio",
    "bevy_gilrs",
    "bevy_gltf",
    "bevy_winit",
    "render",
    "png",
    "hdr",
    "mp3",
    "x11",
]

If I put this in Cargo.toml and run a simple main method (App::build().add_default_plugins().run()), it throws this error:

thread 'thread 'Compute Task Pool (2)Compute Task Pool (1)' panicked at '' panicked at 'Resource does not exist alloc::boxed::Box<dyn bevy_render::renderer::render_resource_context::RenderResourceContext>Resource does not exist alloc::boxed::Box<dyn bevy_render::renderer::render_resource_context::RenderResourceContext>', ', C:\Users\____\.cargo\registry\src\github.202132.xyz-1ecc6299db9ec823\bevy_ecs-0.2.1\src\resource\resources.rsC:\Users\____\.cargo\registry\src\github.202132.xyz-1ecc6299db9ec823\bevy_ecs-0.2.1\src\resource\resources.rs::175175::3232

I don't see any reason to have render depend on wgpu as if I understand the code correctly render uses gfx-hal. If it is an intentional feature, it would be helpful to have a better error message or auto-enable wgpu when render is enabled.

[chemicstry]

Renderer actually uses wgpu, which is based on gfx-hal. I'm not sure about the error though

[entropylost]

Hmm... when I'm compiling with neon I found that enabling bevy_wgpu causes a linking error so I disabled it. It would be very useful if I could use the renderer without bevy_wgpu. (wgpu compiles fine but not bevy_wgpu.)

[cart]

bevy_render cannot render anything by itself. It is a renderer-agnostic interface that different backends can implement. It doesnt have any dependencies on render apis (such as wgpu/gfx-hal/opengl/vulkan/etc). bevy_wgpu is currently the only "real" backend implemented, so if you want to actually render something with Bevy, you will need bevy_wgpu.

bevy_render assumes that there is a backend-specific render resource context registered (for bevy_wgpu this is WgpuRenderResourceContext).

If you want to have the render plugin registered, but not actually render anything, you should be able to add a HeadlessRenderResourceContext, which should suppress the error you're seeing;

    resources.insert::<Box<dyn RenderResourceContext>>(Box::new(HeadlessRenderResourceContext::default()));

[entropylost]

Ah, ok. Could you provide a better error message?

[smokku]

Hmm... when I'm compiling with neon I found that enabling bevy_wgpu causes a linking error so I disabled it. It would be very useful if I could use the renderer without bevy_wgpu. (wgpu compiles fine but not bevy_wgpu.)

Could you create an issue for that?

[cart]

@iMplode-nZ

Ah, ok. Could you provide a better error message?

We can. Feel free to open a PR or issue for it.