renderling 🍖

Renderling is an innovative, GPU-driven renderer designed for efficient scene rendering with a focus on leveraging GPU capabilities for nearly all rendering operations. Utilizing Rust for shader development, it ensures memory safety and cross-platform compatibility, including web platforms. The project, currently in the alpha stage, aims for rapid loading of GLTF files, handling large scenes, and supporting numerous lights. Development emphasizes performance, ergonomics, observability and the use of modern rendering techniques like forward+ rendering and physically based shading.

This project is funded through NGI Zero Core, a fund established by NLnet with financial support from the European Commission's Next Generation Internet program. Learn more at the NLnet project page.

What

renderling holds entire scenes of geometry, textures, materials, lighting, even the scene graph itself - in GPU buffers. All but a few of the rendering operations happen on the GPU. The CPU is used to interact with the filesystem to marshall data to the GPU and to update transforms.

Shaders are written in Rust, via rust-gpu.

Why should I use renderling

• Data is easily staged on the GPU using an automatically reference counted slab allocator that provides access from the CPU.

  Your scene geometry, materials, animations - all of it - live on the GPU, while the CPU has easy access to read and modify that data, without borrowing - allowing you to send your data through threads to anything that needs it.

• Having everything on the GPU makes renderling very effective at rendering certain types of scenes.

  Specifically renderling aims to be good at rendering scenes with a moderate level of unique geometry, (possibly a large amount of repeated geometry), with a small number of large textures (or large number of small textures), and lots of lighting effects.

• Tight integration with GLTF:

  • Loading scenes, nodes, animations etc
  • Includes tools for controlling animations
  • Supported extensions:
    • KHR_lights_punctual
    • KHR_materials_unlit
    • KHR_materials_emissive_strength

• Image based lighting + analytical lighting

• Good documentation

API Features

• builder pattern for scenes, entities (scene nodes), materials and lights
• headless rendering support
  • rendering to texture and saving via image crate
• text rendering support (cargo feature text - on by default)
• nested nodes with local transforms
• tight support for loading scenes through gltf (cargo feature gltf - on by default)

Shaders are written in Rust via rust-gpu where possible, falling back to wgsl where needed.

Rendering Features / Roadmap

Renderling takes a forward+ approach to rendering.

By default it uses a single uber-shader for rendering.

• texture atlas
  • automatic resource management (Arc/drop based)
• GPU slab allocator
  • automatic resource management (Arc/drop based)
• frustum culling
• occlusion culling
• light tiling
• shadow mapping
• 3d
  • Built-in support for common lighting/material workflows
    • physically based shading
    • unlit
  • high dynamic range
  • skybox
  • image based lighting
    • diffuse
    • specular
  • msaa (easy because of forward+)
  • bloom "physically based" up+downsampling blur
  • ssao
  • depth of field
  • gltf support
    • scenes
    • nodes
    • cameras
    • meshes
    • materials
      • pbr metallic roughness (factors + textures)
      • normal mapping
      • occlusion textures
      • pbr specular glosiness
      • parallax mapping
    • textures, images, samplers
    • animation
      • interpolation
      • skinning (still working on one issue)
      • morph targets (requires rebuild)
• 2d (renderling-ui)
  • text
  • stroked and filled paths
    • circles
    • rectangles
    • cubic beziers
    • quadratic beziers
    • arbitrary polygons
    • fill w/ image

Definition

renderling noun

A small beast that looks cute up close, ready to do your graphics bidding.

Haiku

Ghost in the machine, lighting your scene with magic. Cute technology.

Project Organization

• crates/renderling-shader

  Contains Rust shader code that can be shared on CPU and GPU (using rust-gpu to compile to SPIR-V). Most of the shader code is here! Certain tasks require atomics which doesn't work from rust-gpu to wgpu yet. See NOTES.md. This crate is a member of the workspace so you get nice editor tooling while writing shaders in Rust. You can also write sanity tests that run with cargo test. Things just work like BAU.

• shaders

  Contains a thin crate wrapper around renderling-shader. Provides the spirv annotations for shaders. Contains a program that compiles Rust into SPIR-V and copies .spv files into the main renderling crate.

• crates/renderling

  The main crate. Contains CPU Rust code for creating pipelines and managing resources, making render passes, etc. Contains tests, some using image comparison of actual frame renders for consistency and backwards compatibility.

• img

  Image assets for tests (textures, etc.)

• test_img

  Reference images to use for testing.

• crates/example

  Contains an example of using the renderling crate to make an application.

Tests

Tests use renderling in headless mode and generate images that are compared to expected output.

Running tests

cargo test

Building the shaders

The shaders/ folder is a crate that is excluded from the cargo workspace. It compiles into a program that can be run to generate the shaders:

cd shaders/ && cargo run --release

Building on WASM

RUSTFLAGS=--cfg=web_sys_unstable_apis trunk build crates/example-wasm/index.html && basic-http-server -a 127.0.0.1:8080 crates/example-wasm/dist

🫶 Sponsor this!

This work will always be free and open source. If you use it (outright or for inspiration), please consider donating.

💰 Sponsor 💝

Special thanks

• James Harton (@jimsynz) for donating multiple linux CI runners with physical GPUs!

Related work & spin-off projects

Many projects were born from first solving a need within renderling. Some of these solutions were then spun off into their own projects.

• crabslab A slab allocator for working across CPU/GPU boundaries.
• loading-bytes A cross-platform (including the web) and comedically tiny way of loading files to bytes.
• moongraph A DAG and resource graph runner.
• Contributions to naga
  • Adding atomics support to the SPIR-V frontend (in progress)
• Contributions to gltf

Sponsoring this project contributes to the ecosystem.

License

Renderling 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.

Notes & Devlog

I keep a list of (un)organized notes about this project here. I keep a devlog here.