use std::num::NonZeroU32;
use pollster::FutureExt;
use thiserror::Error;
use winit::{
dpi::{LogicalPosition, LogicalSize, PhysicalSize},
error::OsError,
event::{Event, WindowEvent},
event_loop::{ControlFlow, EventLoop},
window::{Fullscreen, Window, WindowBuilder},
};
/// No device could be found which supports the given surface
#[derive(Clone, Copy, Debug, PartialEq, Eq, Error)]
#[error("No GPU could be found on this machine")]
pub struct NoGpuError {
/// Prevents this type from being constructed
_priv: (),
}
impl NoGpuError {
/// Create a new error
const fn new() -> Self {
Self { _priv: () }
}
}
#[derive(Debug, Error)]
pub enum NewRendererError {
#[error(transparent)]
NoGpu(#[from] NoGpuError),
#[error(transparent)]
WindowInitError(#[from] OsError),
}
/// Describes how a window may be resized
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub struct Resizable {
/// The minimum width of the window, or None if unconstrained
pub min_width: Option<NonZeroU32>,
/// The minimum height of the window, or None if unconstrained
pub min_height: Option<NonZeroU32>,
/// The maximum width of the window, or None if unconstrained
pub max_width: Option<NonZeroU32>,
/// The maximum height of the window, or None if unconstrained
pub max_height: Option<NonZeroU32>,
}
/// Information about a window, that is not fullscreened
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct WindowInfo {
pub default_x: i32,
pub default_y: i32,
pub resizable: Option<Resizable>,
pub default_maximized: bool,
}
impl Default for WindowInfo {
fn default() -> Self {
Self {
default_x: 100,
default_y: 100,
resizable: Some(Resizable::default()),
default_maximized: false,
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum WindowMode {
Windowed(WindowInfo),
// TODO support choosing a monitor
BorderlessFullscreen, // TODO exclusive fullscreen
}
impl Default for WindowMode {
fn default() -> Self {
Self::Windowed(WindowInfo::default())
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
// TODO window icon
pub struct RenderWindowConfig {
/// The width of the window, once initialized
pub default_width: NonZeroU32,
/// The height of the window, once initialized
pub default_height: NonZeroU32,
/// The window may be fullscreen
pub mode: WindowMode,
/// The title for the window
pub title: Box<str>,
/// If true, a low-power device will be selected as the GPU, if possible
pub low_power: bool,
/// If true, Fifo mode is used to present frames. If false, then Mailbox or
/// Immediate will be used if available. Otherwise, Fifo will be used.
pub vsync: bool,
}
impl Default for RenderWindowConfig {
fn default() -> Self {
Self {
default_width: NonZeroU32::new(480).unwrap(),
default_height: NonZeroU32::new(640).unwrap(),
mode: WindowMode::default(),
title: "Alligator Game".into(),
low_power: true,
vsync: true,
}
}
}
pub struct Renderer {
surface: wgpu::Surface,
device: wgpu::Device,
queue: wgpu::Queue,
config: wgpu::SurfaceConfiguration,
window: Window,
}
// TODO make this more complete
impl Renderer {
/// Initializes the renderer
///
/// # Errors
///
/// Returns a [`NoGpu`] error if no device could be detected that can
/// display to the window
// TODO make it possible to use without a window (ie, use a bitmap in memory as a surface)
// TODO this function needs to be smaller
#[allow(clippy::missing_panics_doc)]
pub fn new(
config: RenderWindowConfig,
event_loop: &EventLoop<()>,
) -> Result<Self, NewRendererError> {
// start building the window
let mut builder = WindowBuilder::new()
.with_title(config.title)
.with_inner_size(LogicalSize::new(
config.default_width.get(),
config.default_height.get(),
));
match config.mode {
WindowMode::Windowed(window_info) => {
builder = builder.with_maximized(window_info.default_maximized);
if let Some(resizing_options) = window_info.resizable {
if resizing_options.max_height.is_some() || resizing_options.max_width.is_some()
{
builder = builder.with_max_inner_size(LogicalSize::new(
resizing_options.max_width.unwrap_or(NonZeroU32::MAX).get(),
resizing_options.max_height.unwrap_or(NonZeroU32::MAX).get(),
));
}
if resizing_options.min_height.is_some() || resizing_options.min_width.is_some()
{
builder = builder.with_min_inner_size(LogicalSize::new(
resizing_options.min_width.unwrap_or(NonZeroU32::MAX).get(),
resizing_options.min_height.unwrap_or(NonZeroU32::MAX).get(),
));
}
} else {
builder = builder.with_resizable(false);
}
// TODO clamp the position to the monitor's size
builder = builder.with_position(LogicalPosition::new(
window_info.default_x,
window_info.default_y,
));
}
WindowMode::BorderlessFullscreen => {
builder = builder.with_fullscreen(Some(Fullscreen::Borderless(None)));
}
}
let window = builder.build(event_loop)?;
// the instance's main purpose is to create an adapter and a surface
let instance = wgpu::Instance::new(wgpu::Backends::all());
// the surface is the part of the screen we'll draw to
let surface = unsafe { instance.create_surface(&window) };
let power_preference = if config.low_power {
wgpu::PowerPreference::LowPower
} else {
wgpu::PowerPreference::HighPerformance
};
// the adapter is the handle to the GPU
let adapter = instance
.request_adapter(&wgpu::RequestAdapterOptions {
power_preference,
compatible_surface: Some(&surface),
force_fallback_adapter: false,
})
.block_on();
let adapter = adapter.or_else(|| {
instance
.enumerate_adapters(wgpu::Backends::all())
.find(|adapter| !surface.get_supported_formats(adapter).is_empty())
});
let Some(adapter) = adapter else { return Err(NoGpuError::new().into()) };
// gets a connection to the device, as well as a handle to its command queue
// the options chosen here ensure that this is guaranteed to not panic
let (device, queue) = adapter
.request_device(
&wgpu::DeviceDescriptor {
label: None,
features: wgpu::Features::empty(),
limits: wgpu::Limits::default(),
},
None,
)
.block_on()
.unwrap();
let present_mode = if config.vsync {
wgpu::PresentMode::Fifo
} else {
let modes = surface.get_supported_modes(&adapter);
if modes.contains(&wgpu::PresentMode::Mailbox) {
wgpu::PresentMode::Mailbox
} else if modes.contains(&wgpu::PresentMode::Immediate) {
wgpu::PresentMode::Immediate
} else {
wgpu::PresentMode::Fifo
}
};
// configuration for the surface
let config = wgpu::SurfaceConfiguration {
usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
format: surface.get_supported_formats(&adapter)[0],
width: config.default_width.get(),
height: config.default_height.get(),
present_mode,
};
surface.configure(&device, &config);
Ok(Self {
surface,
device,
queue,
config,
window,
})
}
/// Resize just the renderer. The window will remain unchanged
fn resize_renderer(&mut self, size: PhysicalSize<u32>) -> Option<()> {
if size.width == 0 || size.height == 0 {
return None;
}
self.config.height = size.height;
self.config.width = size.width;
self.surface.configure(&self.device, &self.config);
Some(())
}
/// Renders a new frame to the window
///
/// # Errors
///
/// A number of problems could occur here. A timeout could occur while
/// trying to acquire the next frame. There may also be no more memory left
/// that can be used for the new frame.
fn render(&mut self) -> Result<(), wgpu::SurfaceError> {
// the new texture we can render to
let output = self.surface.get_current_texture()?;
let view = output
.texture
.create_view(&wgpu::TextureViewDescriptor::default());
// this will allow us to send commands to the gpu
let mut encoder = self
.device
.create_command_encoder(&wgpu::CommandEncoderDescriptor {
label: Some("Render Encoder"),
});
{
let _render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
label: Some("Render Pass"),
color_attachments: &[Some(wgpu::RenderPassColorAttachment {
view: &view,
resolve_target: None,
ops: wgpu::Operations {
load: wgpu::LoadOp::Clear(wgpu::Color::BLACK),
store: true,
},
})],
depth_stencil_attachment: None,
});
}
// the encoder can't finish building the command buffer until the
// render pass is dropped
// submit the command buffer to the GPU
self.queue.submit(std::iter::once(encoder.finish()));
output.present();
Ok(())
}
/// Run the renderer indefinitely
pub fn run(mut self, event_loop: EventLoop<()>) -> ! {
event_loop.run(move |event, _, control_flow| match event {
Event::WindowEvent { window_id, event } => {
if window_id == self.window.id() {
match event {
WindowEvent::Resized(size) => {
if self.resize_renderer(size).is_none() {
log::error!("Somehow the window was resized to zero?");
}
}
WindowEvent::CloseRequested => *control_flow = ControlFlow::ExitWithCode(0),
_ => (),
}
}
}
Event::RedrawRequested(window_id) => {
if window_id == self.window.id() {
if let Err(e) = self.render() {
log::error!("{}", e);
}
}
}
Event::MainEventsCleared => {
self.window.request_redraw();
}
_ => {}
})
}
}
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