glium 0.31.0

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
#[macro_use]
extern crate glium;

#[allow(unused_imports)]
use glium::{glutin, Surface};

mod support;

fn main() {
    // building the display, ie. the main object
    let event_loop = glutin::event_loop::EventLoop::new();
    let wb = glutin::window::WindowBuilder::new();
    let cb = glutin::ContextBuilder::new().with_depth_buffer(24);
    let display = glium::Display::new(wb, cb, &event_loop).unwrap();

    // building the vertex and index buffers
    let vertex_buffer = support::load_wavefront(&display, include_bytes!("support/teapot.obj"));

    // the program
    let program = program!(&display,
        140 => {
            vertex: "
                #version 140

                uniform mat4 persp_matrix;
                uniform mat4 view_matrix;

                in vec3 position;
                in vec3 normal;
                out vec3 v_position;
                out vec3 v_normal;

                void main() {
                    v_position = position;
                    v_normal = normal;
                    gl_Position = persp_matrix * view_matrix * vec4(v_position * 0.005, 1.0);
                }
            ",

            fragment: "
                #version 140

                in vec3 v_normal;
                out vec4 f_color;

                const vec3 LIGHT = vec3(-0.2, 0.8, 0.1);

                void main() {
                    float lum = max(dot(normalize(v_normal), normalize(LIGHT)), 0.0);
                    vec3 color = (0.3 + 0.7 * lum) * vec3(1.0, 1.0, 1.0);
                    f_color = vec4(color, 1.0);
                }
            ",
        },

        110 => {
            vertex: "
                #version 110

                uniform mat4 persp_matrix;
                uniform mat4 view_matrix;

                attribute vec3 position;
                attribute vec3 normal;
                varying vec3 v_position;
                varying vec3 v_normal;

                void main() {
                    v_position = position;
                    v_normal = normal;
                    gl_Position = persp_matrix * view_matrix * vec4(v_position * 0.005, 1.0);
                }
            ",

            fragment: "
                #version 110

                varying vec3 v_normal;

                const vec3 LIGHT = vec3(-0.2, 0.8, 0.1);

                void main() {
                    float lum = max(dot(normalize(v_normal), normalize(LIGHT)), 0.0);
                    vec3 color = (0.3 + 0.7 * lum) * vec3(1.0, 1.0, 1.0);
                    gl_FragColor = vec4(color, 1.0);
                }
            ",
        },

        100 => {
            vertex: "
                #version 100

                uniform lowp mat4 persp_matrix;
                uniform lowp mat4 view_matrix;

                attribute lowp vec3 position;
                attribute lowp vec3 normal;
                varying lowp vec3 v_position;
                varying lowp vec3 v_normal;

                void main() {
                    v_position = position;
                    v_normal = normal;
                    gl_Position = persp_matrix * view_matrix * vec4(v_position * 0.005, 1.0);
                }
            ",

            fragment: "
                #version 100

                varying lowp vec3 v_normal;

                const lowp vec3 LIGHT = vec3(-0.2, 0.8, 0.1);

                void main() {
                    lowp float lum = max(dot(normalize(v_normal), normalize(LIGHT)), 0.0);
                    lowp vec3 color = (0.3 + 0.7 * lum) * vec3(1.0, 1.0, 1.0);
                    gl_FragColor = vec4(color, 1.0);
                }
            ",
        },
    ).unwrap();

    //
    let mut camera = support::camera::CameraState::new();

    // the main loop
    support::start_loop(event_loop, move |events| {
        camera.update();

        // building the uniforms
        let uniforms = uniform! {
            persp_matrix: camera.get_perspective(),
            view_matrix: camera.get_view(),
        };

        // draw parameters
        let params = glium::DrawParameters {
            depth: glium::Depth {
                test: glium::DepthTest::IfLess,
                write: true,
                .. Default::default()
            },
            .. Default::default()
        };

        // drawing a frame
        let mut target = display.draw();
        target.clear_color_and_depth((0.0, 0.0, 0.0, 0.0), 1.0);
        target.draw(&vertex_buffer,
                    &glium::index::NoIndices(glium::index::PrimitiveType::TrianglesList),
                    &program, &uniforms, &params).unwrap();
        target.finish().unwrap();

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

        // polling and handling the events received by the window
        for event in events {
            match event {
                glutin::event::Event::WindowEvent { event, .. } => match event {
                    glutin::event::WindowEvent::CloseRequested => action = support::Action::Stop,
                    ev => camera.process_input(&ev),
                },
                _ => (),
            }
        };

        action
    });
}