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use std::error::Error;
use wgpu::CompositeAlphaMode;
use wgpu_glyph::{GlyphBrushBuilder, Section, Text, ab_glyph};
const FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Bgra8UnormSrgb;
fn main() -> Result<(), Box<dyn Error>> {
env_logger::init();
// Open window and create a surface
let event_loop = winit::event_loop::EventLoop::new()?;
let window = winit::window::WindowBuilder::new()
.with_resizable(false)
.build(&event_loop)
.unwrap();
let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor::default());
let surface = instance.create_surface(&window)?;
// Initialize GPU
let (device, queue) = futures::executor::block_on(async {
let adapter = instance
.request_adapter(&wgpu::RequestAdapterOptions {
power_preference: wgpu::PowerPreference::HighPerformance,
compatible_surface: Some(&surface),
force_fallback_adapter: false,
})
.await
.expect("Request adapter");
adapter
.request_device(&wgpu::DeviceDescriptor::default())
.await
.expect("Request device")
});
// Create staging belt
let mut staging_belt = wgpu::util::StagingBelt::new(device.clone(), 1024);
// Prepare swap chain and depth buffer
let mut size = window.inner_size();
let mut new_size = None;
let mut depth_view = create_frame_views(&device, &surface, size);
// Prepare glyph_brush
let inconsolata = ab_glyph::FontArc::try_from_slice(include_bytes!(
"Inconsolata-Regular.ttf"
))?;
let mut glyph_brush = GlyphBrushBuilder::using_font(inconsolata)
.depth_stencil_state(wgpu::DepthStencilState {
format: wgpu::TextureFormat::Depth32Float,
depth_write_enabled: true,
depth_compare: wgpu::CompareFunction::Greater,
stencil: wgpu::StencilState::default(),
bias: wgpu::DepthBiasState::default(),
})
.build(&device, FORMAT);
// Render loop
window.request_redraw();
event_loop
.run(move |event, elwt| {
match event {
winit::event::Event::WindowEvent {
event: winit::event::WindowEvent::CloseRequested,
..
} => elwt.exit(),
winit::event::Event::WindowEvent {
event: winit::event::WindowEvent::Resized(size),
..
} => {
new_size = Some(size);
}
winit::event::Event::WindowEvent {
event: winit::event::WindowEvent::RedrawRequested,
..
} => {
if let Some(new_size) = new_size.take() {
depth_view =
create_frame_views(&device, &surface, new_size);
size = new_size;
}
// Get a command encoder for the current frame
let mut encoder = device.create_command_encoder(
&wgpu::CommandEncoderDescriptor {
label: Some("Redraw"),
},
);
// Get the next frame
let frame =
surface.get_current_texture().expect("Get next frame");
let view = &frame
.texture
.create_view(&wgpu::TextureViewDescriptor::default());
// Clear frame
{
let _ = encoder.begin_render_pass(
&wgpu::RenderPassDescriptor {
label: Some("Render pass"),
color_attachments: &[Some(
wgpu::RenderPassColorAttachment {
view,
resolve_target: None,
ops: wgpu::Operations {
load: wgpu::LoadOp::Clear(
wgpu::Color {
r: 0.4,
g: 0.4,
b: 0.4,
a: 1.0,
},
),
store: wgpu::StoreOp::Store,
},
depth_slice: None,
},
)],
depth_stencil_attachment: None,
timestamp_writes: None,
occlusion_query_set: None,
multiview_mask: None,
},
);
}
// Queue text on top, it will be drawn first.
// Depth buffer will make it appear on top.
glyph_brush.queue(Section {
screen_position: (30.0, 30.0),
text: vec![
Text::default()
.with_text("On top")
.with_scale(95.0)
.with_color([0.8, 0.8, 0.8, 1.0])
.with_z(0.9),
],
..Section::default()
});
// Queue background text next.
// Without a depth buffer, this text would be rendered on top of the
// previous queued text.
glyph_brush.queue(Section {
bounds: (size.width as f32, size.height as f32),
text: vec![
Text::default()
.with_text(
&include_str!("lipsum.txt")
.replace("\n\n", "")
.repeat(10),
)
.with_scale(30.0)
.with_color([0.05, 0.05, 0.1, 1.0])
.with_z(0.2),
],
..Section::default()
});
// Draw all the text!
glyph_brush
.draw_queued(
&device,
&mut staging_belt,
&mut encoder,
view,
wgpu::RenderPassDepthStencilAttachment {
view: &depth_view,
depth_ops: Some(wgpu::Operations {
load: wgpu::LoadOp::Clear(0.0),
store: wgpu::StoreOp::Store,
}),
stencil_ops: Some(wgpu::Operations {
load: wgpu::LoadOp::Clear(0),
store: wgpu::StoreOp::Store,
}),
},
size.width,
size.height,
)
.expect("Draw queued");
// Submit the work!
staging_belt.finish();
queue.submit(Some(encoder.finish()));
frame.present();
// Recall unused staging buffers
staging_belt.recall();
}
_ => {}
}
})
.map_err(Into::into)
}
fn create_frame_views(
device: &wgpu::Device,
surface: &wgpu::Surface,
size: winit::dpi::PhysicalSize<u32>,
) -> wgpu::TextureView {
let (width, height) = (size.width, size.height);
surface.configure(
device,
&wgpu::SurfaceConfiguration {
usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
format: FORMAT,
width,
height,
present_mode: wgpu::PresentMode::AutoVsync,
alpha_mode: CompositeAlphaMode::Auto,
view_formats: vec![],
desired_maximum_frame_latency: 2,
},
);
let depth_texture = device.create_texture(&wgpu::TextureDescriptor {
label: Some("Depth buffer"),
size: wgpu::Extent3d {
width,
height,
depth_or_array_layers: 1,
},
mip_level_count: 1,
sample_count: 1,
dimension: wgpu::TextureDimension::D2,
format: wgpu::TextureFormat::Depth32Float,
view_formats: &[],
usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
});
depth_texture.create_view(&wgpu::TextureViewDescriptor::default())
}