116 lines
3.9 KiB
Rust
116 lines
3.9 KiB
Rust
//! A basic self-contained example to get you from zero-to-demo-window as fast
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//! as possible.
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use std::time::Instant;
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use glow::HasContext;
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use glutin::{event_loop::EventLoop, WindowedContext};
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use imgui_winit_support::WinitPlatform;
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const TITLE: &str = "Hello, imgui-rs!";
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type Window = WindowedContext<glutin::PossiblyCurrent>;
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fn main() {
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// Common setup for creating a winit window and imgui context, not specifc
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// to this renderer at all except that glutin is used to create the window
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// since it will give us access to a GL context
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let (event_loop, window) = create_window();
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let (mut winit_platform, mut imgui_context) = imgui_init(&window);
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// OpenGL context from glow
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let gl = glow_context(&window);
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// OpenGL renderer from this crate
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let mut ig_renderer = imgui_glow_renderer::AutoRenderer::initialize(gl, &mut imgui_context)
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.expect("failed to create renderer");
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let mut last_frame = Instant::now();
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// Standard winit event loop
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event_loop.run(move |event, _, control_flow| {
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match event {
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glutin::event::Event::NewEvents(_) => {
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let now = Instant::now();
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imgui_context
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.io_mut()
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.update_delta_time(now.duration_since(last_frame));
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last_frame = now;
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}
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glutin::event::Event::MainEventsCleared => {
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winit_platform
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.prepare_frame(imgui_context.io_mut(), window.window())
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.unwrap();
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window.window().request_redraw();
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}
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glutin::event::Event::RedrawRequested(_) => {
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// The renderer assumes you'll be clearing the buffer yourself
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unsafe { ig_renderer.gl_context().clear(glow::COLOR_BUFFER_BIT) };
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let ui = imgui_context.frame();
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ui.show_demo_window(&mut true);
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winit_platform.prepare_render(ui, window.window());
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let draw_data = imgui_context.render();
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// This is the only extra render step to add
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ig_renderer
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.render(draw_data)
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.expect("error rendering imgui");
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window.swap_buffers().unwrap();
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}
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glutin::event::Event::WindowEvent {
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event: glutin::event::WindowEvent::CloseRequested,
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..
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} => {
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*control_flow = glutin::event_loop::ControlFlow::Exit;
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}
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event => {
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winit_platform.handle_event(imgui_context.io_mut(), window.window(), &event);
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}
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}
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});
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}
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fn create_window() -> (EventLoop<()>, Window) {
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let event_loop = glutin::event_loop::EventLoop::new();
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let window = glutin::window::WindowBuilder::new()
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.with_title(TITLE)
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.with_inner_size(glutin::dpi::LogicalSize::new(1024, 768));
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let window = glutin::ContextBuilder::new()
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.with_vsync(true)
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.build_windowed(window, &event_loop)
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.expect("could not create window");
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let window = unsafe {
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window
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.make_current()
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.expect("could not make window context current")
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};
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(event_loop, window)
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}
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fn glow_context(window: &Window) -> glow::Context {
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unsafe { glow::Context::from_loader_function(|s| window.get_proc_address(s).cast()) }
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}
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fn imgui_init(window: &Window) -> (WinitPlatform, imgui::Context) {
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let mut imgui_context = imgui::Context::create();
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imgui_context.set_ini_filename(None);
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let mut winit_platform = WinitPlatform::init(&mut imgui_context);
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winit_platform.attach_window(
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imgui_context.io_mut(),
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window.window(),
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imgui_winit_support::HiDpiMode::Rounded,
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);
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imgui_context
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.fonts()
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.add_font(&[imgui::FontSource::DefaultFontData { config: None }]);
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imgui_context.io_mut().font_global_scale = (1.0 / winit_platform.hidpi_factor()) as f32;
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(winit_platform, imgui_context)
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}
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