vello_hybrid: Allow binding multiple external textures per draw call (#1858) This PR adds support for binding up to 4 external textures in a single draw call. This is achieved by simply making use of more shader slots (which WebGL2 guarantees to support at least 16, so we are still well below the limit) and changing the CPU batching algorithm to support multiple external images in a single pass. This reduces the number of draw calls emitted, but does make the shader more branchy. Once we move to specialized shaders, we should carefully re-evaluate whether the branching makes image rendering slower, but for our current uber shader it does not seem to make a difference. And our previous experiments have shown that the CPU-side overhead of draw calls can also be considerable, so in this regard this PR is an improvement. The main motivation for this PR however is to enable the follow-up PR that removes 2D texure arrays to keep the draw count minimal.
A GPU compute-centric 2D renderer
The Vello project is a set of high-performance vector renderers written in Rust:
Quickstart to run an example program:
cargo run -p with_winit
Significant changes are documented in the changelog.
Vello is meant to fill the same place in the graphics stack as other vector graphics renderers like Skia, Cairo, and its predecessor project Piet. On a basic level, that means it provides tools to render shapes, images, gradients, text, etc, using a PostScript-inspired API, the same that powers SVG files and the browser <canvas> element.
The selling point of Vello's implementations is that they get better performance than other renderers by better leveraging the SIMD, multithreading and the GPU.
This version of Vello has been verified to compile with Rust 1.89 and later.
Future versions of Vello might increase the Rust version requirement. It will not be treated as a breaking change and as such can even happen with small patch releases.
As time has passed, some of Vello‘s dependencies could have released versions with a higher Rust requirement. If you encounter a compilation issue due to a dependency and don’t want to upgrade your Rust toolchain, then you could downgrade the dependency.
# Use the problematic dependency's name and version cargo update -p package_name --precise 0.1.1
Discussion of Vello development happens in the Linebender Zulip, specifically the #vello channel. All public content can be read without logging in.
Contributions are welcome by pull request. The Rust code of conduct applies.
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 licensed as noted in the License section, without any additional terms or conditions.
Licensed under either of
at your option.
In addition, all files in the vello_shaders/shader and vello_shaders/src/cpu directories and subdirectories thereof are alternatively licensed under the Unlicense (vello_shaders/shader/UNLICENSE or http://unlicense.org/). For clarity, these files are also licensed under either of the above licenses. The intent is for this research to be used in as broad a context as possible.
The files in subdirectories of the examples/assets directory are licensed solely under their respective licenses, available in the LICENSE file in their directories.