Shape

https://github.com/glium/glium/blob/master/book/tuto-07-shape.md

더 복잡한 Shape

삼각형을 그리는 대신 더 복잡한 모양인 찻주전자를 표현
Utah teapot은 종종 그래픽 프로그래밍의 "hello world" 중 하나로 간주되는 유명한 3D 모델

teapot model data in rust
이 파일에는 3개의 배열이 존재

• vertex 배열
• normal 배열
• index 배열

그래픽스에서 3D model 표현은 삼각형의 집합으로 표현하는데, vertex의 중복을 막기위해 index 배열을 사용하여 3D model을 표현
index 배열의 각 요소는 실제로 vertex 및 normal 배열의 인덱스
세개의 index가 하나의 삼각형을 표현

Shape 로딩

teapot을 사용하기위해 위 링크의 파일을 프로젝트에 추가하고 코드에 아래 코드를 사용

mod teapot;

데이터 로딩

let positions = glium::VertexBuffer::new(&display, &teapot::VERTICES).unwrap();
let normals = glium::VertexBuffer::new(&display, &teapot::NORMALS).unwrap();
let indices = glium::IndexBuffer::new(&display, glium::index::PrimitiveType::TrianglesList,
                                      &teapot::INDICES).unwrap();

The program

vertex shader 수정

#version 140

in vec3 position;
in vec3 normal;

uniform mat4 matrix;

void main() {
    gl_Position = matrix * vec4(position, 1.0);
}

fragment shader 수정

#version 140

out vec4 color;

void main() {
    color = vec4(1.0, 0.0, 0.0, 1.0);
}

Drawing

drawing code 수정

let matrix = [
    [0.01, 0.0, 0.0, 0.0],
    [0.0, 0.01, 0.0, 0.0],
    [0.0, 0.0, 0.01, 0.0],
    [0.0, 0.0, 0.0, 1.0f32]
];

target.draw((&positions, &normals), &indices, &program, &uniform! { matrix: matrix },
            &Default::default()).unwrap();

전체코드

#[macro_use]
extern crate glium;

mod teapot;

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

    let mut event_loop = glutin::event_loop::EventLoop::new();
    let wb = glutin::window::WindowBuilder::new();
    let cb = glutin::ContextBuilder::new();
    let display = glium::Display::new(wb, cb, &event_loop).unwrap();

    let positions = glium::VertexBuffer::new(&display, &teapot::VERTICES).unwrap();
    let normals = glium::VertexBuffer::new(&display, &teapot::NORMALS).unwrap();
    let indices = glium::IndexBuffer::new(
        &display,
        glium::index::PrimitiveType::TrianglesList,
        &teapot::INDICES,
    )
    .unwrap();

    let vertex_shader_src = r#"
    #version 140

    in vec3 position;
    in vec3 normal;

    uniform mat4 matrix;

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

    let fragment_shader_src = r#"
    #version 140

    out vec4 color;

    void main() {
        color = vec4(1.0, 0.0, 0.0, 1.0);
    }
"#;

    let program =
        glium::Program::from_source(&display, vertex_shader_src, fragment_shader_src, None)
            .unwrap();

    let mut t: f32 = -0.5;
    event_loop.run(move |event, _, control_flow| {
        match event {
            glutin::event::Event::WindowEvent { event, .. } => match event {
                glutin::event::WindowEvent::CloseRequested => {
                    *control_flow = glutin::event_loop::ControlFlow::Exit;
                    return;
                }
                _ => return,
            },
            glutin::event::Event::NewEvents(cause) => match cause {
                glutin::event::StartCause::ResumeTimeReached { .. } => (),
                glutin::event::StartCause::Init => (),
                _ => return,
            },
            _ => return,
        }

        let next_frame_time =
            std::time::Instant::now() + std::time::Duration::from_nanos(16_666_667);
        *control_flow = glutin::event_loop::ControlFlow::WaitUntil(next_frame_time);

        t += 0.002;
        if t > 0.5 {
            t = -0.5;
        }

        let uniforms = uniform! {
            // matrix: [
            //     [ t.cos(), t.sin(), 0.0, 0.0],
            //     [-t.sin(), t.cos(), 0.0, 0.0],
            //     [0.0, 0.0, 1.0, 0.0],
            //     [0.0, 0.0, 0.0, 1.0f32],
            // ]
            matrix: [
                [0.01, 0.0, 0.0, 0.0],
                [0.0, 0.01, 0.0, 0.0],
                [0.0, 0.0, 0.01, 0.0],
                [0.0, 0.0, 0.0, 1.0f32]
            ]
        };

        let mut target = display.draw();
        target.clear_color(0.3, 0.5, 0.7, 1.0);
        target
            .draw(
                (&positions, &normals),
                &indices,
                &program,
                &uniforms,
                &Default::default(),
            )
            .unwrap();
        target.finish().unwrap();
    });
}