Hotline

Hotline is a live coding tool where you can editor code, shaders, render pipelines, render graphs and more without restarting the application. It provides a host application which remains running for the duration of a session. Code can be reloaded that is inside the dynamic lib and render pipelines and shaders can be edited and hot reloaded through pmfx files.

Prequisites

Currently Windows with Direct3D12 is the only suppported platform, there are plans for macOS, Metal, Linux Vulkan and more over time.

pmbuild and pmfx-shader are required for building data and shaders, they are bundled with the repository.

If you are using hotline from crates.io then the executables are not bundeled because this exceeds the 10mb package size limit. You can clone this repository to get the executables (stick them into hotline_rs/bin/win32) or download the pmbuild release manualy and then boostrap the rest of the process:

./build.cmd update

The config.jsn is used to configure pmbuild build jobs and tools, if you wanted to manually configure the setup.

Building

First build the live lib and then build the host executable and data (data will be built automatically when using cargo build). Then run the host:

text cargo build -p lib cargo build cargo run host

Once the host is running, any changes made to the source code in lib.rs or the pipelines will be automatically reloaded into the running application.

Examples

There are a few standalone examples of how to use the lower level components of hotline (gfx, app, av). You can build and run these as follows:

text cargo build --examples cargo run --example triangle

VScode

There are included tasks and launch files for vscode including configurations for the host and the examples.

Design Goals

• An easy to use cross platform graphics/compute/os api for rapid development.
• Hot reloadable, live coding environment (shaders, render graphs, code).
• Concise low level graphics api... think somewhere in-between Metal and Direct3D12.
• High level data driven graphics api for ease of use and speed.
• A focus on modern rendering examples (gpu-driven, multi-threaded, bindless, ray-tracing).
• Flexibility to easily create and use different rendering strategies (deferred vs forward, gpu-driven vs cpu driven, etc).
• Hardware accellerated video decoding.
• Fibre based, multi-threaded, easily scalable to utilise available cpu and gpu.
• Data-driven and configurable.
• Plugin based and extendible...

Roadmap

In Progress

• Debug / Primitve Rendering API
• High level graphics api (render graphs, data driven, Uber shaders)
• Multi-threading support (async command buffer generation and job dispatches)
• Samples and Demos
• ~~Hot reloading~~
• ~~API (gfx::, os::) / Backend (d3d12::, win32::)~~
• ~~API (av::) / Windows Media Foundation (HW Video / Audio Decoding)~~
• ~~Imgui support w/ Viewports~~

Future Plans

• Linux
• Vulkan
• macOS
• Metal
• AV Foundation
• WASM
• WebGPU

Contributing

Contributions of all kinds are welcome, you can make a fork and send a PR if you want to submit small fixes or improvements. Anyone interseted in being more involved in development I am happy to take on people to help with project of all experience levels, especially people with more experience in Rust. You can contact me if interested via Twitter or Discord.