glium 0.19.0

Elegant and safe OpenGL wrapper. Glium is an intermediate layer between OpenGL and your application. You still need to manually handle the graphics pipeline, but without having to use OpenGL's old and error-prone API. Its objectives: - Be safe to use. Many aspects of OpenGL that can trigger a crash if misused are automatically handled by glium. - Provide an API that enforces good pratices such as RAII or stateless function calls. - Be compatible with all OpenGL versions that support shaders, providing unified API when things diverge. - Avoid all OpenGL errors beforehand. - Produce optimized OpenGL function calls, and allow the user to easily use modern OpenGL techniques.
Documentation 
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#[macro_use]
extern crate glium;

extern crate image;

use std::io::Cursor;

use glium::Surface;
use glium::index::PrimitiveType;
use glium::glutin::{self, ElementState, VirtualKeyCode, Event, WindowEvent};

mod support;

fn main() {
    // building the display, ie. the main object
    let mut events_loop = glutin::EventsLoop::new();
    let window = glutin::WindowBuilder::new();
    let context = glutin::ContextBuilder::new();
    let display = glium::Display::new(window, context, &events_loop).unwrap();

    // building a texture with "OpenGL" drawn on it
    let image = image::load(Cursor::new(&include_bytes!("../tests/fixture/opengl.png")[..]),
                            image::PNG).unwrap().to_rgba();
    let image_dimensions = image.dimensions();
    let image = glium::texture::RawImage2d::from_raw_rgba_reversed(&image.into_raw(), image_dimensions);
    let opengl_texture = glium::texture::CompressedTexture2d::new(&display, image).unwrap();

    // building the vertex buffer, which contains all the vertices that we will draw
    let vertex_buffer = {
        #[derive(Copy, Clone)]
        struct Vertex {
            position: [f32; 2],
            tex_coords: [f32; 2],
        }

        implement_vertex!(Vertex, position, tex_coords);

        glium::VertexBuffer::new(&display, 
            &[
                Vertex { position: [-1.0, -1.0], tex_coords: [0.0, 0.0] },
                Vertex { position: [-1.0,  1.0], tex_coords: [0.0, 1.0] },
                Vertex { position: [ 1.0,  1.0], tex_coords: [1.0, 1.0] },
                Vertex { position: [ 1.0, -1.0], tex_coords: [1.0, 0.0] }
            ]
        ).unwrap()
    };

    // building the index buffer
    let index_buffer = glium::IndexBuffer::new(&display, PrimitiveType::TriangleStrip,
                                               &[1 as u16, 2, 0, 3]).unwrap();

    // compiling shaders and linking them together
    let program = glium::Program::from_source(&display, r"
        #version 140

        uniform mat4 matrix;

        in vec2 position;
        in vec2 tex_coords;

        out vec2 v_tex_coords;

        void main() {
            gl_Position = matrix * vec4(position, 0.0, 1.0);
            v_tex_coords = tex_coords;
        }
    ", r"
        #version 140
        uniform sampler2D tex;
        in vec2 v_tex_coords;
        out vec4 color;

        void main() {
            color = texture(tex, v_tex_coords);
        }
    ", None).unwrap();


    let mut fullscreen = false;

    println!("Press Enter to switch fullscreen mode");

    support::start_loop(|| {
        // drawing a frame
        let mut target = display.draw();
        target.clear_color(0.0, 1.0, 0.0, 1.0);
        target.draw(&vertex_buffer, &index_buffer, &program, &uniform! { 
                matrix: [
                    [0.5, 0.0, 0.0, 0.0],
                    [0.0, 0.5, 0.0, 0.0],
                    [0.0, 0.0, 0.5, 0.0],
                    [0.0, 0.0, 0.0, 1.0f32]
                ],
                tex: &opengl_texture
            }, &Default::default()).unwrap();
        target.finish().unwrap();

        let mut action = support::Action::Continue;

        // polling and handling the events received by the window
        let mut enter_pressed = false;
        events_loop.poll_events(|event| match event {
            Event::WindowEvent { event, window_id } =>
                if window_id == display.gl_window().id() {
                    match event {
                        WindowEvent::Closed => action = support::Action::Stop,
                        WindowEvent::KeyboardInput { input, .. } => {
                            if let ElementState::Pressed = input.state {
                                if let Some(VirtualKeyCode::Return) = input.virtual_keycode {
                                    enter_pressed = true;
                                }
                            }
                        },
                        _ => ()
                    }
                },
            _ => (),
        });

        // If enter was pressed toggle fullscreen.
        if enter_pressed {
            if fullscreen {
                let window = glutin::WindowBuilder::new();
                let context = glutin::ContextBuilder::new();
                display.rebuild(window, context, &events_loop).unwrap();
                fullscreen = false;
            } else {
                let window = glutin::WindowBuilder::new()
                    .with_fullscreen(Some(events_loop.get_primary_monitor()));
                let context = glutin::ContextBuilder::new();
                display.rebuild(window, context, &events_loop).unwrap();
                fullscreen = true;
            }
        }

        action
    });
}