Add Grass

[CuddlyBunion341]

Grass

The landscape was feeling very baren and the next logical step from trees is grass. The grass proposed in this PR consists of a cross mesh with two intersecting grass sprites.
(100% without the use of AI 🎉)

1. Create meshes for all blocks that should be represented by a cross instead of a cube
2. Find all positions of blocks in chunk that have cross representation
3. Add cross mesh instance at block position to the scene

Note

The initial idea with the mesh instancing was too slow and was thus replaced with a more performant approach, having two meshes per chunk, one transparent, the other popaque. All the cross meshes get combined into a single mesh. (b2dc458). Grouping the meshes did not in fact break transparency, which made the optimization possible.

Known Problems

• Performance is worse, as meshes are not grouped, this would break transparency (See note above)
• Self shadows make the grass too dark from certain angles (no idea how to fix that)

Notes

Todo

Server

• Add randomly spawning tallgrass on grassblocks
• Add params for configuring frequency
• Add slider for grass frequency

Client

• Add tallgrass texture to atlas
• Update texture atlas record
• Update client side representation of blocks
• Update mesher to accept grass (use instancing?)
• Update colliders to ignore grass
• Update culler to ignore grass
• Update raycaster hit location vector when hitting grass -> lets make grass non selectable
• Check that transparency doesn't look like dog water
• Mesh cleanup

[CuddlyBunion341]

Almost ready

[CuddlyBunion341]

lgtm

[SemiShogun]

so... you can finally touch grass now?