Rust gfx triangle example using SDL2

triangle.rs

// Copyright 2014 The Gfx-rs Developers.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

extern crate sdl2; // 0.18.0
#[macro_use]
extern crate gfx; // 0.12.2
extern crate gfx_window_sdl; // 0.3.0

use sdl2::event::Event;
use gfx::traits::FactoryExt;
use gfx::Device;

gfx_defines!{
    vertex Vertex {
        pos: [f32; 2] = "a_Pos",
        color: [f32; 3] = "a_Color",
    }

    pipeline pipe {
        vbuf: gfx::VertexBuffer<Vertex> = (),
        out: gfx::RenderTarget<gfx::format::Srgba8> = "Target0",
    }
}

const VERTEX_SHADER: &'static [u8] = br##"#version 150 core

in vec2 a_Pos;
in vec3 a_Color;
out vec4 v_Color;

void main() {
    v_Color = vec4(a_Color, 1.0);
    gl_Position = vec4(a_Pos, 0.0, 1.0);
}
"##;

const FRAGMENT_SHADER: &'static [u8] = br##"#version 150 core

in vec4 v_Color;
out vec4 Target0;

void main() {
    Target0 = v_Color;
}
"##;

const TRIANGLE: [Vertex; 3] = [
    Vertex { pos: [ -0.5, -0.5 ], color: [1.0, 0.0, 0.0] },
    Vertex { pos: [  0.5, -0.5 ], color: [0.0, 1.0, 0.0] },
    Vertex { pos: [  0.0,  0.5 ], color: [0.0, 0.0, 1.0] }
];

const CLEAR_COLOR: [f32; 4] = [0.1, 0.2, 0.3, 1.0];

pub fn main() {
    let sdl = sdl2::init().unwrap();

    let mut builder = sdl.video().unwrap().window("Triangle", 800, 600);
    let (window, _gl, mut device, mut factory, color_view, _depth_view) =
        gfx_window_sdl::init(&mut builder);

    let command_buffer = factory.create_command_buffer();
    let mut encoder: gfx::Encoder<_, _> = command_buffer.into();
    let pso = factory.create_pipeline_simple(
        VERTEX_SHADER,
        FRAGMENT_SHADER,
        pipe::new()
    ).unwrap();
    let (vertex_buffer, slice) = factory.create_vertex_buffer_with_slice(&TRIANGLE, ());
    let data = pipe::Data {
        vbuf: vertex_buffer,
        out: color_view
    };

    let mut events = sdl.event_pump().unwrap();
    'main: loop {
        for event in events.poll_iter() {
            match event {
                Event::Quit { .. } => {
                    break 'main;
                },
                _ => { }
            }
        }

        encoder.clear(&data.out, CLEAR_COLOR);
        encoder.draw(&slice, &pso, &data);
        encoder.flush(&mut device);
        window.gl_swap_window();
        device.cleanup();
    }
}