WebGL State Machine in Rust

An opinionated wrapper for low-level WebGL API with intention to provide a bit of explicit state management with reasonable defaults. Primary goals for this library is to support WebGL 1.0 so it is built on top of raw bindings from web-sys crate.

Key concepts

• Program - GL program description including vertex shader, fragment shader, attributes and uniforms. Program takes care of compiling shaders, getting attributes / uniforms locations and finally disposing resources once it goes out of scope.
• Mesh - structure that holds references to data uploaded to GPU, takes care of disposing array / element buffers once it goes out of scope.
• Framebuffer - render target, has depth and color slot, can also be initialized as empty then rendering would go to the screen.
• Pipeline - a primitive for drawing stuff to screen, sole purpose of which is to set GL context configuration and provide shade method for drawing.

Usage example

Get it from crates.io

```toml [dependencies]

...

glsmrs = "0.2.0" ```

Import crate

rust use glsmrs as gl;

Create context, Ctx is a wrapper that is using Rc internally so you can clone it and pass around without worrying too much about lifetimes.

rust let ctx = gl::util::get_ctx("canvas-name", "webgl")?;

Create some mesh, like an RGB triangle

```rust let vertices = vec![[0.5, -0.5], [0.0, 0.5], [-0.5, -0.5]]; let colors = vec![[1., 0., 0.], [0., 1., 0.], [0., 0., 1.]]; let indices = [0, 1, 2];

let triangle = gl::mesh::Mesh::new(&ctx, &indices)? .withattribute::("position", &vertices)? .withattrubute::("color", &colors)?; ```

Define render target

rust let viewport = gl::texture::Viewport::new(720, 480); let displayfb = gl::texture::EmptyFramebuffer::new(&ctx, viewport);

Create a program description

rust let program = gl::Program::new( &ctx, include_str!("../shaders/dummy.vert"), include_str!("../shaders/dummy.frag"), )?;

Run program on state supplying necessary inputs

```rust let uniforms: HashMap<_, _> = vec![ ("time", gl::UniformData::Scalar(time as f32)), ].into_iter().collect();

let pipeline = gl::Pipeline::new(&ctx);

pipeline.shade( &program, uniforms, vec![&mut triangle], &mut displayfb )?; ```

For example project using this library check out [ https://github.com/wg-romank/wasm-game-of-life ] a tweaked version of original WASM tutorial that runs entierly on GPU.