Don't resize when viewport 0x0

[Dispersia]

This is a hack to prevent wgpu from crashing bevy when size set to a width or height of 0. Wgpu currently crashes on its swapchain under this condition, winit sends a resize event (of 0x0) on minimize, and if the user click and drag resizes to 0 width or 0 height it crashes as well.

You will not get an event of a 0 width or 0 height resize, so if you want to check for minimized you would need to check window flags on the winit window (I don't think you should check 0x0 for minimized regardless)

This should be removed when gfx-rs/wgpu-rs#316 is fixed

Fixes #170

[DJMcNab]

I feel like we should fix this in the rendering pipeline side (i.e. in bevy_wgpu), by just not rendering anything to the surface at all.
I don't know how feasible this is however

[cart]

Its a tough call. I agree that doing it in bevy_wgpu is nice because it scopes the problem, but it also means that render state is then out of sync with window state. This hack seems fine because it makes "bevy's view of the world" consistent.

@Dispersia I'm down to merge this, but can we add a comment to the code that explains the hack and links to the wgpu issue?

[DJMcNab]

I feel like gfx-rs/wgpu-rs#531 or gfx-rs/wgpu-rs#316 are perhaps more relevant; that is I don't think gfx-rs/wgpu-rs#352 is actually persuant to this issue, as that is about any resizing on vulkan, not this issue which is resizing to a zero-dimensioned window.

[cart]

Hmm looks like Wgpu worked around this in their examples by ensuring swap chain textures are always > 0 (basically what @DJMcNab suggested). I guess we should probably use their approach and link to the issues @DJMcNab called out.

[Dispersia]

Sounds good, I will make that change instead. Seems strange since we can try to manipulate the view in a different state, but this is a weird issue in the first place

[alice-i-cecile]

I think this should be closed in favor of #1409.