gl_helpers 0.1.1

extern crate gl;
extern crate glutin;
extern crate time;
extern crate rand;
extern crate mat4;
extern crate gl_helpers;


use std::f32::consts::PI;

use glutin::GlContext;
use gl::types::*;

use rand::{weak_rng, Rng};
use gl_helpers::*;


static TO_RADS: f32 = PI / 180f32;

const TEX_WIDTH: usize = 512;
const TEX_HEIGHT: usize = TEX_WIDTH;
const TEX_SIZE: usize = TEX_WIDTH * TEX_HEIGHT;

static SIMPLE_VERTEX_DATA: [GLfloat; 16] = [
    //   position     uv
     1f32,  1f32,   1f32, 1f32,
    -1f32,  1f32,   0f32, 1f32,
     1f32, -1f32,   1f32, 0f32,
    -1f32, -1f32,   0f32, 0f32
];

static SIMPLE_VERTEX: &'static str = "
    #version 120

    uniform mat4 projection;
    uniform mat4 model_view;

    uniform vec2 uv_offset;

    attribute vec2 position;
    attribute vec2 uv;

    varying vec2 v_uv;

    void main() {
        gl_Position = projection * model_view * vec4(position, 0.0, 1.0);
        v_uv = uv_offset + uv;
    }
";

static SIMPLE_FRAGMENT: &'static str = "
    #version 120

    uniform sampler2D diffuse;

    varying vec2 v_uv;

    void main() {
        gl_FragColor = texture2D(diffuse, v_uv);
    }
";

fn main() {
    let mut screen_width = 1024_usize;
    let mut screen_height = 768_usize;

    let mut events_loop = glutin::EventsLoop::new();
    let window = glutin::WindowBuilder::new()
        .with_title("Simple")
        .with_dimensions(screen_width as u32, screen_height as u32);
    let gl_window = glutin::GlWindow::new(
        window,
        glutin::ContextBuilder::new()
            .with_vsync(true),
        &events_loop
    ).unwrap();

    unsafe {
        gl_window.make_current().unwrap();
    }

    gl::load_with(|symbol| gl_window.get_proc_address(symbol) as *const _);

    let gl_info = GLInfo::new();
    println!("{}", gl_info.version());
    println!(
        "OpenGL version: {:?}.{:?}, GLSL version {:?}.{:?}0",
        gl_info.major(), gl_info.minor(), gl_info.glsl_major(), gl_info.glsl_minor()
    );

    gl_set_defaults();

    let mut random = weak_rng();
    let mut data = [0xffffffffu32; TEX_SIZE];

    for i in 0..TEX_SIZE {
        let r = (random.next_f32() * 256f32) as u32;
        let c = (0xff000000) | (r << 16) | (r << 8) | r;
        data[i] = c;
    }

    let texture = GLTexture::new_2d(
        TEX_WIDTH,
        TEX_HEIGHT,
        DataFormat::RGBA,
        DataKind::UnsignedByte,
        FilterMode::Linear,
        Wrap::Repeat,
        true,
        &data
    );


    let program = GLProgram::new(SIMPLE_VERTEX, SIMPLE_FRAGMENT);

    let buffer = GLBuffer::new(BufferTarget::Array, 4, Usage::StaticDraw, &SIMPLE_VERTEX_DATA);

    let mut vertex_array = GLVertexArray::new();

    vertex_array.bind();
    vertex_array.add_attribute(&buffer, program.get_attribute("position"), 0);
    vertex_array.add_attribute(&buffer, program.get_attribute("uv"), 2);

    vertex_array.enable_attributes();

    let mut playing = true;

    let start_time = time::now();
    let mut last_time = start_time;
    let mut current_time;
    let mut ms = 0f32;
    let mut dt;

    let mut projection = mat4::new_identity::<f32>();
    let mut model_view = mat4::new_identity::<f32>();
    let mut camera = [0f32, 0f32, -5f32];
    let mut uv_offset = [0f32, 0f32];
    let mut color = [0f32, 0f32, 0f32, 1f32];

    while playing {
        current_time = time::now();
        dt = (current_time - last_time).num_nanoseconds().unwrap() as f32 * 0.000001f32;
        ms += dt;
        last_time = current_time;

        events_loop.poll_events(|event| {
            match event {
                glutin::Event::WindowEvent { event: glutin::WindowEvent::Closed, .. } => {
                    playing = false;
                },
                glutin::Event::WindowEvent { event: glutin::WindowEvent::Resized(w, h), .. } => {
                    screen_width = w as usize;
                    screen_height = h as usize;

                    gl_window.resize(w, h);
                    gl_set_viewport(0, 0, screen_width, screen_height);
                    mat4::perspective(&mut projection, 45f32 * TO_RADS, w as f32 / h as f32, 0.01f32, 1024f32);
                },
                glutin::Event::WindowEvent { event: glutin::WindowEvent::MouseMoved{ position, .. }, .. } => {
                    let (x, y) = position;
                    let x = x as f32;
                    let y = y as f32;
                    let w = screen_width as f32;
                    let h = screen_height as f32;
                    camera[0] = ((x - (w / 2f32)) / w) * 2f32;
                    camera[1] = (((h / 2f32) - y) / w) * 2f32;
                },
                _ => (),
            }
        });

        color[0] = (ms * 0.000001f32).cos();
        color[1] = (ms * 0.0001f32).sin();
        color[2] = (ms * 0.001f32).cos();

        uv_offset[0] = (ms * 0.0001f32).sin() * 0.5f32;
        uv_offset[1] = (ms * 0.0001f32).cos() * 0.5f32;

        mat4::set_position(&mut model_view, &camera);

        gl_set_clear_color(&color);
        gl_clear(true, true, true);

        program.bind();
        vertex_array.bind();
        vertex_array.enable_attributes();

        program.get_uniform("diffuse").set_sampler_2d(&texture, 0);
        program.get_uniform("uv_offset").set_2f(&uv_offset);
        program.get_uniform("projection").set_mat4f(&projection);
        program.get_uniform("model_view").set_mat4f(&model_view);

        gl_draw_arrays(DrawMode::TriangleStrip, 0, 4);

        gl_window.swap_buffers().unwrap();
    }
}