Ability to draw meshes in 2d with the new renderer

[Ixentus]

What problem does this solve or what need does it fill?

Using the old renderer it was possible to draw shapes using meshes with SpriteBundles. However with the new renderer SpriteBundles no longer have Meshes and Materials. I've tried to convert them to PbrBundles instead, but nothing gets drawn. This might be because there is no lighting. François said on Discord that custom meshes in 2d are not supported by default anymore.

What solution would you like?

I'm not sure what the best solution to fix this would be since I'm very new to rendering, but one of the following might do:

• Automatic lighting for 2d
• A new bundle for 2d meshes
• A modified pipeline for 2d

Additional context

Alternative ways to draw custom shapes also exist. However both bevy_lyon and bevy_svg also use meshes in their implementations and haven't been updated yet.

[Nilirad]

It may be possible that you don't see nothing because of backface culling. In PBR pipeline, the vertex order for a front face is counterclockwise. If you draw shapes clockwise (e.g. using Lyon) you won't see nothing despite the data being present in the GPU.

[Ixentus]

It may be possible that you don't see nothing because of backface culling. In PBR pipeline, the vertex order for a front face is counterclockwise. If you draw shapes clockwise (e.g. using Lyon) you won't see nothing despite the data being present in the GPU.

I tried flipping a mesh a 180 degrees around X, no effect.

[Weasy666]

PbrBundles only work with a 3D camera, because a Mesh only registers a draw function to DrawFunctions<Transparent3d>. At least that is what i have seen so far.

[cart]

I think a new Mesh2dBundle is probably the move here. The biggest challenge will be ensuring that it interacts with sprite batches properly (which in practice just means that we need to split sprite batches at the z-index of every non-batched 2d entity ... shouldn't be too hard).

[cart]

Fixed by #3460