Add egui_glow backend as alternative to egui_glium

ARCHITECTURE.md

@@ -36,6 +36,10 @@ Puts an egui app inside the web browser by compiling to WASM and binding to the
 ### `egui_glium`
 Puts an egui app inside a native window on your laptop. Paints the triangles that egui outputs using [glium](https://github.com/glium/glium).
 
+### `egui_glow`
+Puts an egui app inside a native window on your laptop. Paints the triangles that egui outputs using [glow](https://github.com/grovesNL/glow).
+An alternative to `egui_glium`, not used by `eframe` at this time.
+
 ### `eframe`
 A wrapper around `egui_web` + `egui_glium`, so you can compile the same app for either web or native.
 

README.md

@@ -163,11 +163,12 @@ The integration needs to do two things:
 
 ### Official
 
-I maintain two official egui integrations made for apps:
+There are three official egui integrations made for apps:
 
 * [`egui_web`](https://github.com/emilk/egui/tree/master/egui_web) for making a web app. Compiles to WASM, renders with WebGL. [Click to run the egui demo](https://emilk.github.io/egui/index.html).
 * [`egui_glium`](https://github.com/emilk/egui/tree/master/egui_glium) for compiling native apps with [Glium](https://github.com/glium/glium).
-* [`egui-winit`](https://github.com/emilk/egui/tree/master/egui-winit) for integrating with [`winit`](https://github.com/rust-windowing/winit). `egui-winit` is used by `egui_glium`.
+* [`egui_glow`](https://github.com/emilk/egui/tree/master/egui_glow) for compiling native apps with [Glow](https://github.com/grovesNL/glow).
+* [`egui-winit`](https://github.com/emilk/egui/tree/master/egui-winit) for integrating with [`winit`](https://github.com/rust-windowing/winit). `egui-winit` is used by `egui_glium` and `egui_glow`.
 
 If you making an app, consider using [`eframe`](https://github.com/emilk/egui/tree/master/eframe), a framework which allows you to write code that works on both the web (`egui_web`) and native (using `egui_glium`).
 
@@ -211,7 +212,7 @@ loop {
 }
 ```
 
-For a reference OpenGL backend, see [the `egui_glium` painter](https://github.com/emilk/egui/blob/master/egui_glium/src/painter.rs) or [the `egui_web` `WebGL` painter](https://github.com/emilk/egui/blob/master/egui_web/src/webgl1.rs).
+For a reference OpenGL backend, see [the `egui_glium` painter](https://github.com/emilk/egui/blob/master/egui_glium/src/painter.rs), [the `egui_glow` painter](https://github.com/emilk/egui/blob/master/egui_glow/src/painter.rs), or [the `egui_web` `WebGL` painter](https://github.com/emilk/egui/blob/master/egui_web/src/webgl1.rs).
 
 ### Debugging your integration
 

eframe/CHANGELOG.md

@@ -9,6 +9,7 @@ NOTE: [`egui_web`](egui_web/CHANGELOG.md), [`egui-winit`](egui-winit/CHANGELOG.m
 * Remove "http" feature (use https://github.com/emilk/ehttp instead!).
 * Increase native scroll speed.
 * Add `App::persist_native_window` and `App::persist_egui_memory` to control what gets persisted.
+* Add new backend `egui_glow` as an alternative to `egui_glium` (not yet exposed as a feature flag)
 
 
 ## 0.14.0 - 2021-08-24

egui_glow/CHANGELOG.md

@@ -0,0 +1,8 @@
+# Changelog for egui_glow
+All notable changes to the `egui_glow` integration will be noted in this file.
+
+
+## Unreleased
+`egui_glow` has been newly created, with feature parity to `egui_glium`.
+As `glow` is a set of lower-level bindings to OpenGL, this crate is potentially less stable than `egui_glium`,
+but there are no known issues, and the crate will only become more stable over time, if any issues manifest.

egui_glow/Cargo.toml

@@ -0,0 +1,70 @@
+[package]
+name = "egui_glow"
+version = "0.14.0"
+authors = ["Emil Ernerfeldt <[email protected]>"]
+description = "Bindings for using egui natively using the glow library"
+edition = "2018"
+homepage = "https://github.com/emilk/egui/tree/master/egui_glow"
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+repository = "https://github.com/emilk/egui/tree/master/egui_glow"
+categories = ["gui", "game-development"]
+keywords = ["glow", "egui", "gui", "gamedev"]
+include = [
+  "../LICENSE-APACHE",
+  "../LICENSE-MIT",
+  "**/*.rs",
+  "Cargo.toml",
+  "src/shader/*.glsl",
+]
+
+[package.metadata.docs.rs]
+all-features = true
+
+[dependencies]
+egui = { version = "0.14.0", path = "../egui", default-features = false, features = ["single_threaded"] }
+egui-winit = { version = "0.14.0", path = "../egui-winit", default-features = false }
+epi = { version = "0.14.0", path = "../epi" }
+glutin = "0.27"
+glow = "0.11"
+memoffset = "0.6"
+
+# feature "persistence":
+directories-next = { version = "2", optional = true }
+ron = { version = "0.6", optional = true }
+serde = { version = "1", optional = true }
+
+# feature "time"
+chrono = { version = "0.4", optional = true }
+
+[dev-dependencies]
+image = { version = "0.23", default-features = false, features = ["png"] }
+
+[features]
+default = ["clipboard", "default_fonts", "links"]
+
+# enable cut/copy/paste to OS clipboard.
+# if disabled a clipboard will be simulated so you can still copy/paste within the egui app.
+clipboard = ["egui-winit/clipboard"]
+
+# If set, egui will use `include_bytes!` to bundle some fonts.
+# If you plan on specifying your own fonts you may disable this feature.
+default_fonts = ["egui/default_fonts"]
+
+# enable opening links in a browser when an egui hyperlink is clicked.
+links = ["egui-winit/links"]
+
+persistence = [
+    "directories-next",
+    "egui-winit/serialize",
+    "egui/persistence",
+    "epi/persistence",
+    "ron",
+    "serde",
+]
+
+# experimental support for a screen reader
+screen_reader = ["egui-winit/screen_reader"]
+
+# for seconds_since_midnight (used in egui_demo_lib)
+time = ["chrono"]

egui_glow/README.md

@@ -0,0 +1,16 @@
+# egui_glow
+
+[![Latest version](https://img.shields.io/crates/v/egui_glow.svg)](https://crates.io/crates/egui_glow)
+[![Documentation](https://docs.rs/egui_glow/badge.svg)](https://docs.rs/egui_glow)
+![MIT](https://img.shields.io/badge/license-MIT-blue.svg)
+![Apache](https://img.shields.io/badge/license-Apache-blue.svg)
+
+This crates provides bindings between [`egui`](https://github.com/emilk/egui) and [glow](https://crates.io/crates/glow) which allows you to write GUI code using egui and compile it and run it natively, cross platform.
+
+To use on Linux, first run:
+
+```
+sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev libspeechd-dev libxkbcommon-dev libssl-dev
+```
+
+This crate depends on [`egui-winit`](https://github.com/emilk/egui/tree/master/egui-winit).

egui_glow/examples/pure.rs

@@ -0,0 +1,130 @@
+//! Example how to use pure `egui_glow` without [`epi`].
+
+fn create_display(
+    event_loop: &glutin::event_loop::EventLoop<()>,
+) -> (
+    glutin::WindowedContext<glutin::PossiblyCurrent>,
+    glow::Context,
+) {
+    let window_builder = glutin::window::WindowBuilder::new()
+        .with_resizable(true)
+        .with_inner_size(glutin::dpi::LogicalSize {
+            width: 800.0,
+            height: 600.0,
+        })
+        .with_title("egui_glow example");
+
+    let gl_window = unsafe {
+        glutin::ContextBuilder::new()
+            .with_depth_buffer(0)
+            .with_srgb(true)
+            .with_stencil_buffer(0)
+            .with_vsync(true)
+            .build_windowed(window_builder, event_loop)
+            .unwrap()
+            .make_current()
+            .unwrap()
+    };
+
+    let gl = unsafe { glow::Context::from_loader_function(|s| gl_window.get_proc_address(s)) };
+
+    unsafe {
+        use glow::HasContext;
+        gl.enable(glow::FRAMEBUFFER_SRGB);
+    }
+
+    (gl_window, gl)
+}
+
+fn main() {
+    let event_loop = glutin::event_loop::EventLoop::with_user_event();
+    let (gl_window, gl) = create_display(&event_loop);
+
+    let mut egui = egui_glow::EguiGlow::new(&gl_window, &gl);
+
+    event_loop.run(move |event, _, control_flow| {
+        let mut redraw = || {
+            egui.begin_frame(gl_window.window());
+
+            let mut quit = false;
+
+            egui::SidePanel::left("my_side_panel").show(egui.ctx(), |ui| {
+                ui.heading("Hello World!");
+                if ui.button("Quit").clicked() {
+                    quit = true;
+                }
+
+                egui::ComboBox::from_label("Version")
+                    .width(150.0)
+                    .selected_text("foo")
+                    .show_ui(ui, |ui| {
+                        egui::CollapsingHeader::new("Dev")
+                            .default_open(true)
+                            .show(ui, |ui| {
+                                ui.label("contents");
+                            });
+                    });
+            });
+
+            let (needs_repaint, shapes) = egui.end_frame(gl_window.window());
+
+            *control_flow = if quit {
+                glutin::event_loop::ControlFlow::Exit
+            } else if needs_repaint {
+                gl_window.window().request_redraw();
+                glutin::event_loop::ControlFlow::Poll
+            } else {
+                glutin::event_loop::ControlFlow::Wait
+            };
+
+            {
+                let clear_color = egui::Rgba::from_rgb(0.1, 0.3, 0.2);
+                unsafe {
+                    use glow::HasContext;
+                    gl.clear_color(
+                        clear_color[0],
+                        clear_color[1],
+                        clear_color[2],
+                        clear_color[3],
+                    );
+                    gl.clear(glow::COLOR_BUFFER_BIT);
+                }
+
+                // draw things behind egui here
+
+                egui.paint(&gl_window, &gl, shapes);
+
+                // draw things on top of egui here
+
+                gl_window.swap_buffers().unwrap();
+            }
+        };
+
+        match event {
+            // Platform-dependent event handlers to workaround a winit bug
+            // See: https://github.com/rust-windowing/winit/issues/987
+            // See: https://github.com/rust-windowing/winit/issues/1619
+            glutin::event::Event::RedrawEventsCleared if cfg!(windows) => redraw(),
+            glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
+
+            glutin::event::Event::WindowEvent { event, .. } => {
+                if egui.is_quit_event(&event) {
+                    *control_flow = glutin::event_loop::ControlFlow::Exit;
+                }
+
+                if let glutin::event::WindowEvent::Resized(physical_size) = event {
+                    gl_window.resize(physical_size);
+                }
+
+                egui.on_event(&event);
+
+                gl_window.window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
+            }
+            glutin::event::Event::LoopDestroyed => {
+                egui.destroy(&gl);
+            }
+
+            _ => (),
+        }
+    });
+}