use std::{convert::TryInto, mem::size_of, num::NonZeroU32};
use crate::{instance::InstanceId, vertex::SQUARE, Instance, RenderWindowConfig, Vertex};
use pollster::FutureExt;
use thiserror::Error;
use wgpu::{include_wgsl, util::DeviceExt};
use winit::{
dpi::PhysicalSize,
error::OsError,
event::{Event, WindowEvent},
event_loop::{ControlFlow, EventLoop},
window::Window,
};
/// No device could be found which supports the given surface
#[derive(Clone, Copy, Debug, 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),
}
#[derive(Debug)]
pub struct Renderer {
surface: wgpu::Surface,
surface_config: wgpu::SurfaceConfiguration,
supported_present_modes: Box<[wgpu::PresentMode]>,
device: wgpu::Device,
queue: wgpu::Queue,
render_pipeline: wgpu::RenderPipeline,
square_vertex_buffer: wgpu::Buffer,
square_vertices: u32,
instance_buffer: wgpu::Buffer,
instance_buffer_size: usize,
instances: Vec<Instance>,
window: Window,
}
// TODO make this more complete
impl Renderer {
fn get_adapter(
instance: &wgpu::Instance,
surface: &wgpu::Surface,
power_preference: wgpu::PowerPreference,
) -> Result<wgpu::Adapter, NoGpuError> {
let adapter = instance
.request_adapter(&wgpu::RequestAdapterOptions {
power_preference,
compatible_surface: Some(surface),
force_fallback_adapter: false,
})
.block_on(); // TODO this takes too long
let adapter = adapter.or_else(|| {
instance
.enumerate_adapters(wgpu::Backends::all())
.find(|adapter| !surface.get_supported_formats(adapter).is_empty())
});
adapter.ok_or(NoGpuError::new())
}
fn sprite_render_pipeline(
device: &wgpu::Device,
texture_format: wgpu::TextureFormat,
) -> wgpu::RenderPipeline {
let shader = device.create_shader_module(include_wgsl!("../shaders/sprite.wgsl"));
let render_pipeline_layout =
device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
label: Some("Sprite Render Pipeline Layout"),
..Default::default()
});
device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
label: Some("Sprite Render Pipeline"),
layout: Some(&render_pipeline_layout),
// information about the vertex shader
vertex: wgpu::VertexState {
module: &shader,
entry_point: "vs_main",
buffers: &[Vertex::desc(), Instance::desc()],
},
// information about the fragment shader
fragment: Some(wgpu::FragmentState {
module: &shader,
entry_point: "fs_main",
targets: &[Some(wgpu::ColorTargetState {
format: texture_format,
blend: Some(wgpu::BlendState::REPLACE),
write_mask: wgpu::ColorWrites::ALL,
})],
}),
primitive: wgpu::PrimitiveState {
// don't render the back of a sprite
cull_mode: Some(wgpu::Face::Back),
..Default::default()
},
depth_stencil: None,
multisample: wgpu::MultisampleState::default(),
multiview: None,
})
}
fn new_instance_buffer(
device: &wgpu::Device,
instances: &Vec<Instance>,
) -> (wgpu::Buffer, usize) {
let instance_buffer_size = instances.capacity();
let instance_buffer = device.create_buffer(&wgpu::BufferDescriptor {
label: Some("Sprite Instance Buffer"),
size: (instance_buffer_size * size_of::<Instance>()) as wgpu::BufferAddress,
usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
mapped_at_creation: false,
});
(instance_buffer, instance_buffer_size)
}
/// Initializes the renderer
///
/// # Errors
///
/// Returns a [`NoGpu`] error if no device could be detected that can
/// display to the window
///
/// # Panics
///
/// This function **must** be called on the main thread, or else it may
/// panic on some platforms.
// 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
pub fn new(
config: &RenderWindowConfig,
event_loop: &EventLoop<()>,
) -> Result<Self, NewRendererError> {
// build the window
let window = config.to_window().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 = config.power_preference();
// the adapter is the handle to the GPU
let adapter = Self::get_adapter(&instance, &surface, power_preference)?;
// 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 {
features: wgpu::Features::empty(),
..Default::default()
},
None,
)
.block_on()
.expect("there was no device with the selected features");
// configuration for the surface
let supported_present_modes = surface.get_supported_modes(&adapter).into_boxed_slice();
let surface_config = config.to_surface_configuration(
&surface.get_supported_modes(&adapter),
surface.get_supported_formats(&adapter)[0],
);
surface.configure(&device, &surface_config);
// set up a pipeline for sprite rendering
let render_pipeline = Self::sprite_render_pipeline(&device, surface_config.format);
// the vertex buffer used for rendering squares
let square_vertices = SQUARE
.len()
.try_into()
.expect("expected fewer than 3 billion vertices in a square");
let square_vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some("Square Vertex Buffer"),
contents: bytemuck::cast_slice(&SQUARE),
usage: wgpu::BufferUsages::VERTEX,
});
// create the instance buffer
let instances = Vec::with_capacity(config.instance_capacity);
let (instance_buffer, instance_buffer_size) =
Self::new_instance_buffer(&device, &instances);
Ok(Self {
surface,
surface_config,
supported_present_modes,
device,
queue,
render_pipeline,
square_vertex_buffer,
square_vertices,
instance_buffer,
instance_buffer_size,
instances,
window,
})
}
fn reconfigure(&mut self) {
self.surface.configure(&self.device, &self.surface_config);
}
/// Resize just the renderer. The window will remain unchanged
fn resize_renderer(&mut self, size: PhysicalSize<u32>) {
if size.width == 0 || size.height == 0 {
log::error!("The window was somehow set to a size of zero");
return;
}
self.surface_config.height = size.height;
self.surface_config.width = size.width;
self.reconfigure();
}
/// Set the physical window and renderer size
pub fn resize(&mut self, width: NonZeroU32, height: NonZeroU32) {
let size = PhysicalSize::new(width.get(), height.get());
self.window.set_inner_size(size);
self.resize_renderer(size);
}
/// Set vsync on or off. See `[RenderWindowConfig::present_mode]` for more details.
pub fn set_vsync(&mut self, vsync: bool) {
self.surface_config.present_mode =
RenderWindowConfig::present_mode(vsync, &self.supported_present_modes);
self.reconfigure();
}
/// Set the window's title
pub fn set_title(&mut self, title: &str) {
self.window.set_title(title);
}
fn expand_instance_buffer(&mut self) {
(self.instance_buffer, self.instance_buffer_size) =
Self::new_instance_buffer(&self.device, &self.instances);
}
fn fill_instance_buffer(&mut self) {
if self.instances.len() > self.instance_buffer_size {
self.expand_instance_buffer();
}
self.queue.write_buffer(
&self.instance_buffer,
0 as wgpu::BufferAddress,
bytemuck::cast_slice(&self.instances),
);
}
/// Add an instance to the renderer, and returns an `InstanceId` to the
/// instance. This id becomes invalid if the instances are cleared.
pub fn push_instance(&mut self, instance: Instance) -> InstanceId {
let index = self.instances.len();
self.instances.push(instance);
InstanceId(index)
}
/// Get a mutable reference to an instance
pub fn instance_mut(&mut self, id: InstanceId) -> Option<&mut Instance> {
self.instances.get_mut(id.0)
}
/// Clears the list of instances, making all instance ID's invalid
pub fn clear_instances(&mut self) {
self.instances.clear();
}
/// 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"),
});
self.fill_instance_buffer();
let num_instances = self
.instances
.len()
.try_into()
.expect("expected less than 3 billion instances");
{
let mut 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,
});
render_pass.set_pipeline(&self.render_pipeline);
render_pass.set_vertex_buffer(0, self.square_vertex_buffer.slice(..));
render_pass.set_vertex_buffer(1, self.instance_buffer.slice(..));
render_pass.draw(0..self.square_vertices, 0..num_instances);
}
// 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<()>) -> ! {
self.window.set_visible(true);
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) => self.resize_renderer(size),
WindowEvent::CloseRequested => *control_flow = ControlFlow::ExitWithCode(0),
_ => (),
}
}
}
Event::MainEventsCleared => {
match self.render() {
Ok(_) => {}
// reconfigure the surface if it's been lost
Err(wgpu::SurfaceError::Lost) => {
self.reconfigure();
}
// if we ran out of memory, then we'll die
Err(wgpu::SurfaceError::OutOfMemory) => {
*control_flow = ControlFlow::ExitWithCode(1);
}
// otherwise, we'll just log the error
Err(e) => log::error!("{}", e),
}
}
_ => {}
})
}
}
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