Better error message when render is used without wgpu.

[entropylost]

I think there should be a better error message when the render plugin is used without wgpu. The current error message is very unhelpful (see below), and could be improved.

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.com-1ecc6299db9ec823\bevy_ecs-0.2.1\src\resource\resources.rsC:\Users\____\.cargo\registry\src\github.com-1ecc6299db9ec823\bevy_ecs-0.2.1\src\resource\resources.rs::175175::3232

I would suggest panicking with an error message like "Render backend not found. Currently, the render plugin needs the wgpu plugin to be supported; maybe that should be enabled?"

[GabCampbell]

Seems like a good point. Developer experience should definitely be a top priority. Thanks for the suggestion. Do you have a suggested implementation for this feature?

[DJMcNab]

See also #622

[entropylost]

@GabLotus I don't actually know how bevy works at all, so no. Also, it seems that CorePlugin has a dependency on TypeRegistryPlugin, which should also be fixed. (also which plugin has the event loop...)

[memoryruins]

it seems that CorePlugin has a dependency on TypeRegistryPlugin, which should also be fixed.

It uses the RegisterType trait for the plugin
https://docs.rs/bevy_type_registry/0.2.1/bevy_type_registry/trait.RegisterType.html

bevy/crates/bevy_core/src/lib.rs

Lines 36 to 38 in 9a4167e

	.register_component::<Timer>()
	.register_property::<Vec2>()
	.register_property::<Vec3>()

also which plugin has the event loop

The high-level runner is in bevy_app, which either uses bevy_app::ScheduleRunner or bevy_winit::winit_runner if there is windowing.