bevy-vertex-pulling

Vertex pulling is a useful and efficient technique for drawing many quads or cubes by storing per-instance data in a buffer, indexing into it using an index calculated based on the vertex index, and calculating offsets from a world position for the instance based on which vertex of the quad/cube is being processed.

Running quads-instanced example in the browser

With Just and simple-http-server

Step 1

From the command line and in the directory with the justfile run just serve and all of the manual steps noted above will be run in order

Step 2

Navigate to http://localhost:3000/generated/quads-instanced.html in the browser

Manually from the command line and with simple-http-server

Step 1

cargo build --release --target wasm32-unknown-unknown --example quads-instanced

Step 2

wasm-bindgen --out-dir generated --web target/wasm32-unknown-unknown/release/examples/quads-instanced.wasm

Step 3

simple-http-server --port 3000 --nocache

Step 4

Navigate to http://localhost:3000/generated/quads-instanced.html in the browser

Approaches Implemented

• Instance data stored in:
  • Storage buffer
• Shapes
  • Quads
  • Cuboids/voxels

Things to do/try

• Instance data storage
  • Instance buffer
  • Texture buffer
  • Reusable abstraction
• Reduce overdraw
  • Depth prepass
  • Sorting from front to back
  • Tighter containing geometry
    • Triangle mesh to draw quads and discard like alpha mask
    • Bevy circular texture with a triangle mesh and discard like alpha mask
    • Bevy circular texture with a circular mesh
• Support more basic shapes
• Support complex meshes
• Billboarding (make the planar shape face the camera)
• Culling
  • Compute shader-based frustum culling
  • Compute shader-based occlusion culling
• Compute shader software rasterisation when the shape is small on-screen as raster shades fragments using 2x2 'pixel quads'
  • https://research.nvidia.com/publication/2011-08_high-performance-software-rasterization-gpus
  • https://raphlinus.github.io/
  • https://www.cg.tuwien.ac.at/research/publications/2021/SCHUETZ-2021-PCC/

License

bevy-vertex-pulling is free and open source! All code in this repository is dual-licensed under either:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option. This means you can select the license you prefer! This dual-licensing approach is the de-facto standard in the Rust ecosystem and there are very good reasons to include both.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.