glium 0.29.1

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 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

#[macro_use]
extern crate glium;

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

mod support;

fn main() {
    println!("This example draws 10,000 instanced teapots. Each teapot gets a random position and \
              direction at initialization. Then the CPU updates and uploads the positions of each \
              teapot at each frame.");

    // 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"));
    let indices = glium::index::NoIndices(glium::index::PrimitiveType::TrianglesList);

    // list of teapots with position and direction
    let mut teapots = (0 .. 10000)
        .map(|_| {
            let pos: (f32, f32, f32) = (rand::random(), rand::random(), rand::random());
            let dir: (f32, f32, f32) = (rand::random(), rand::random(), rand::random());
            let pos = (pos.0 * 1.5 - 0.75, pos.1 * 1.5 - 0.75, pos.2 * 1.5 - 0.75);
            let dir = (dir.0 * 1.5 - 0.75, dir.1 * 1.5 - 0.75, dir.2 * 1.5 - 0.75);
            (pos, dir)
        })
        .collect::<Vec<_>>();

    // building the vertex buffer with the attributes per instance
    let mut per_instance = {
        #[derive(Copy, Clone)]
        struct Attr {
            world_position: (f32, f32, f32),
        }

        implement_vertex!(Attr, world_position);

        let data = teapots.iter().map(|_| {
            Attr {
                world_position: (0.0, 0.0, 0.0),
            }
        }).collect::<Vec<_>>();

        glium::vertex::VertexBuffer::dynamic(&display, &data).unwrap()
    };

    let program = glium::Program::from_source(&display,
        "
            #version 140

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

            void main() {
                v_position = position;
                v_normal = normal;
                v_color = vec3(float(gl_InstanceID) / 10000.0, 1.0, 1.0);
                gl_Position = vec4(position * 0.0005 + world_position, 1.0);
            }
        ",
        "
            #version 140

            in vec3 v_normal;
            in vec3 v_color;
            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) * v_color;
                f_color = vec4(color, 1.0);
            }
        ",
        None)
        .unwrap();

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

    // the main loop
    support::start_loop(event_loop, move |events| {
        // updating the teapots
        {
            let mut mapping = per_instance.map();
            for (src, dest) in teapots.iter_mut().zip(mapping.iter_mut()) {
                (src.0).0 += (src.1).0 * 0.001;
                (src.0).1 += (src.1).1 * 0.001;
                (src.0).2 += (src.1).2 * 0.001;

                dest.world_position = src.0;
            }
        }

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

        let mut target = display.draw();
        target.clear_color_and_depth((0.0, 0.0, 0.0, 0.0), 1.0);
        target.draw((&vertex_buffer, per_instance.per_instance().unwrap()),
                    &indices, &program, &uniform! { matrix: camera.get_perspective() },
                    &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,
                    _ => (),
                },
                _ => (),
            }
        };

        action
    });
}