Crate cotis_wgpu 

wgpu-backed desktop renderer for the Cotis UI ecosystem.

cotis-wgpu implements Cotis’s cotis::renders::CotisRenderer and cotis::renders::CotisRendererAsync traits on top of wgpu 24, winit 0.30, and glyphon 0.8. It is a drop-in alternative to other Cotis render backends such as cotis-raylib.

Quick start

For interactive applications, create a CotisWgpuRenderer and wire it into CotisApp (from cotis::cotis_app) with a layout manager and pipe:

use cotis::cotis_app::{CotisApp, RenderApp};
use cotis_layout::preamble::CotisLayoutManager;
use cotis_pipes::cotis_layout_pipes::CotisLayoutToRenderListPipeForGenerics;
use cotis_utils::math::Dimensions;
use cotis_wgpu::prelude::*;

let renderer = CotisWgpuRenderer::auto_start();
let manager = CotisLayoutManager::new(Dimensions::new(1000.0, 800.0));
let mut app = CotisApp::new(renderer, manager, CotisLayoutToRenderListPipeForGenerics);

while !app.render().window_should_close() {
    RenderApp::compute_frame(&mut app, |root| {
        // build UI on root
    });
}

For the full wiring pattern including a StandardRenderCmds type alias, see examples/basic_example/support.rs in this crate’s source tree.

Run the shipped example from the workspace root:

cargo run --example basic_example -p cotis-wgpu

Recommended imports

Use prelude for the common entry-point types:

use cotis_wgpu::prelude::*;

Rendering model

CotisWgpuRenderer draws three kinds of command streams:

• cotis_defaults::render_commands::render_t_list::RenderTList with a nested list type — typed heterogeneous command lists produced by layout pipes (primary path with cotis-pipes).
• cotis_defaults::render_commands::render_t_list::RenderTList with () as the list tail — single-command lists.
• Box<dyn drawable::WgpuDrawable> — type-erased custom commands; implement drawable::WgpuDrawable for types not covered by cotis-defaults commands.

Each cotis::renders::CotisRenderer::draw_frame call pumps the winit event loop before presenting. CotisWgpuRenderer::window_should_close also pumps events, so the typical app loop calls app.render() (which invokes draw_frame) and then checks window_should_close().

Built-in drawing for standard cotis-defaults commands lives in default_drawables. Custom commands can use the advanced pipeline, surface, and text modules directly.

Cotis trait implementations

CotisWgpuRenderer also implements Cotis context and interactivity traits. See cotis_traits for the full list, including:

• cotis_utils::traits::CotisWindowContext — physical window dimensions in pixels.
• cotis_utils::traits::CotisFrameContext — frame delta time.
• cotis_utils::traits::CotisRenderContext — render marker trait.
• cotis_utils::text::RendererTextMeasuringProvider — glyphon text measurement.
• cotis_utils::interactivity::mouse::MouseProvider and keyboard providers via input.

Features

Feature	Effect
complex-color	Enables cotis-defaults/complex_color and complex_colored_text. Accepts ColorLayer types but does not render gradients — see default_drawables.

Known limitations

• Fonts: All text uses glyphon Family::SansSerif. TextConfig::font_id is ignored; there is no font-loading API.
• Images: cotis_defaults::render_commands::Image commands render as colored rectangles; texture loading is not implemented.
• Geometry alpha: The UI shader outputs opaque fragments; cotis color alpha is ignored for rectangles and borders (text alpha is preserved via glyphon).
• Async renderer: cotis::renders::CotisRendererAsync delegates synchronously to cotis::renders::CotisRenderer; there is no async GPU work.
• Frame errors: Present failures log a warning and skip the frame; the application continues.

Public modules

Module	Role
prelude	Application entry-point re-exports
renderer	CotisWgpuRenderer, WindowConfig, event loop
error	WgpuBackendError
drawable	drawable::WgpuDrawable extension trait
default_drawables	Built-in WgpuDrawable impls for cotis-defaults commands
cotis_traits	Cotis context/interactivity trait impls
color	Cotis Color → wgpu conversions
input	winit input snapshot
pipeline	Advanced: UI geometry batch and WGSL pipeline
surface	Advanced: swapchain and depth buffer
text	Advanced: glyphon text batching

Re-exports

pub use error::WgpuBackendError;

pub use renderer::CotisWgpuRenderer;

pub use renderer::WindowConfig;

Modules

color

Color conversion between cotis and wgpu representations.

cotis_traits

Cotis context and interactivity trait implementations for crate::renderer::CotisWgpuRenderer.

default_drawables

crate::drawable::WgpuDrawable implementations for standard cotis-defaults render commands.

drawable

Custom render command extension point for the wgpu backend.

error

Initialization and presentation errors for the wgpu backend.

input

Input state collected from winit and exposed through Cotis interactivity traits.

pipeline

Advanced extension API: UI geometry batch and WGSL render pipeline.

prelude

Convenient re-exports for application code.

renderer

CotisWgpuRenderer and window configuration for the wgpu backend.

surface

Advanced extension API: swapchain surface and depth buffer.

text

Advanced extension API: glyphon text batching for a single frame.