glium 0.5.3

High-level and safe OpenGL wrapper.
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#[macro_use]
extern crate glium;

#[cfg(feature = "image")]
extern crate image;

#[cfg(feature = "image")]
use std::io::Cursor;

#[cfg(feature = "image")]
use glium::{DisplayBuild, Surface};
use glium::glutin;
use glium::index::PrimitiveType;

mod support;

#[cfg(not(feature = "image"))]
fn main() {
    println!("This example requires the `image` feature to be enabled");
}

#[cfg(feature = "image")]
fn main() {
    // building the display, ie. the main object
    let display = glutin::WindowBuilder::new()
        .with_vsync()
        .build_glium()
        .unwrap();

    // building a texture with "OpenGL" drawn on it
    let image = image::load(Cursor::new(&include_bytes!("../tests/fixture/opengl.png")[..]),
        image::PNG).unwrap();
    let opengl_texture = glium::texture::CompressedSrgbTexture2d::new(&display, image);

    // 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, 
            vec![
                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] }
            ]
        )
    };

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

    // compiling shaders and linking them together
    let program = program!(&display,
        140 => {
            vertex: "
                #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;
                }
            ",

            fragment: "
                #version 140
                uniform sampler2D tex;
                in vec2 v_tex_coords;
                out vec4 f_color;

                void main() {
                    f_color = texture(tex, v_tex_coords);
                }
            "
        },

        110 => {  
            vertex: "
                #version 110

                uniform mat4 matrix;

                attribute vec2 position;
                attribute vec2 tex_coords;

                varying vec2 v_tex_coords;

                void main() {
                    gl_Position = matrix * vec4(position, 0.0, 1.0);
                    v_tex_coords = tex_coords;
                }
            ",

            fragment: "
                #version 110
                uniform sampler2D tex;
                varying vec2 v_tex_coords;

                void main() {
                    gl_FragColor = texture2D(tex, v_tex_coords);
                }
            ",
        },

        100 => {  
            vertex: "
                #version 100

                uniform lowp mat4 matrix;

                attribute lowp vec2 position;
                attribute lowp vec2 tex_coords;

                varying lowp vec2 v_tex_coords;

                void main() {
                    gl_Position = matrix * vec4(position, 0.0, 1.0);
                    v_tex_coords = tex_coords;
                }
            ",

            fragment: "
                #version 100
                uniform lowp sampler2D tex;
                varying lowp vec2 v_tex_coords;

                void main() {
                    gl_FragColor = texture2D(tex, v_tex_coords);
                }
            ",
        },
    ).unwrap();
    
    // the main loop
    support::start_loop(|| {
        // building the uniforms
        let uniforms = uniform! {
            matrix: [
                [1.0, 0.0, 0.0, 0.0],
                [0.0, 1.0, 0.0, 0.0],
                [0.0, 0.0, 1.0, 0.0],
                [0.0, 0.0, 0.0, 1.0f32]
            ],
            tex: &opengl_texture
        };

        // drawing a frame
        let mut target = display.draw();
        target.clear_color(0.0, 0.0, 0.0, 0.0);
        target.draw(&vertex_buffer, &index_buffer, &program, &uniforms, &Default::default()).unwrap();
        target.finish();

        // polling and handling the events received by the window
        for event in display.poll_events() {
            match event {
                glutin::Event::Closed => return support::Action::Stop,
                _ => ()
            }
        }

        support::Action::Continue
    });
}