Added gfx-rs support

Cargo.toml

@@ -27,6 +27,10 @@ git = "https://github.com/PistonDevelopers/piston"
 
 git = "https://github.com/bjz/gl-rs"
 
+[dependencies.gfx]
+
+git = "https://github.com/gfx-rs/gfx-rs"
+
 [[lib]]
 
 name = "sdl2_game_window"

src/concurrent_window_sdl2.rs

@@ -1,6 +1,9 @@
 //! RenderWindow and ConcurrentWindow implemented by SDL2 back-end.
 
 // External crates.
+use gfx;
+use gfx::DeviceHelper;
+use device;
 use std;
 use sdl2;
 use piston::{
@@ -145,4 +148,14 @@ impl ConcurrentWindowSDL2 {
         );
 
     }
+
+    /// Creates a gfx device and front end.
+    pub fn gfx(&self) -> (device::GlDevice, gfx::FrontEnd) {
+        let mut device = device::GlDevice::new(|s| unsafe {
+            std::mem::transmute(sdl2::video::gl_get_proc_address(s))
+        });
+        let (w, h) = self.get_size();
+        let frontend = device.create_frontend(w as u16, h as u16).unwrap();
+        (device, frontend)
+    }
 }

src/game_window_sdl2.rs

@@ -1,6 +1,8 @@
 //! A window implemented by SDL2 back-end.
 
 // External crates.
+use gfx;
+use device;
 use sdl2;
 use piston::{
     GameWindow,
@@ -35,6 +37,11 @@ impl GameWindowSDL2 {
             render_window: render_window,
         }
     }
+
+    /// Creates a gfx devince and front end.
+    pub fn gfx(&self) -> (device::GlDevice, gfx::FrontEnd) {
+        self.concurrent_window.gfx()
+    }
 }
 
 impl GameWindow for GameWindowSDL2 {

src/lib.rs

@@ -6,6 +6,8 @@
 extern crate sdl2;
 extern crate piston;
 extern crate gl;
+extern crate gfx;
+extern crate device;
 
 pub use GameWindowSDL2 = game_window_sdl2::GameWindowSDL2;
 pub use ConcurrentWindowSDL2 = concurrent_window_sdl2::ConcurrentWindowSDL2;