Add egui_glow backend as alternative to egui_glium (#685)

egui_glow/Cargo.toml

@@ -0,0 +1,70 @@
+[package]
+name = "egui_glow"
+version = "0.14.0"
+authors = ["Emil Ernerfeldt <emil.ernerfeldt@gmail.com>"]
+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"]