Division is more expensive than multiplication, and this doesn't seem to be optimize away, so iterating over `(0..height)` and `(0..width)` provides better performance. It's good to have the example show the best way to write code using softbuffer, and this helps when using examples as a benchmark. This will also be needed if Softbuffer supports formats where `stride` isn't just `width * pixel_size`, and needs alignment.
102 lines
3.2 KiB
Rust
102 lines
3.2 KiB
Rust
use std::num::NonZeroU32;
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use winit::event::{ElementState, Event, KeyboardInput, VirtualKeyCode, WindowEvent};
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use winit::event_loop::{ControlFlow, EventLoop};
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use winit::window::WindowBuilder;
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fn redraw(buffer: &mut [u32], width: usize, height: usize, flag: bool) {
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for y in 0..height {
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for x in 0..width {
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let value = if flag && x >= 100 && x < width - 100 && y >= 100 && y < height - 100 {
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0x00ffffff
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} else {
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let red = (x & 0xff) ^ (y & 0xff);
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let green = (x & 0x7f) ^ (y & 0x7f);
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let blue = (x & 0x3f) ^ (y & 0x3f);
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(blue | (green << 8) | (red << 16)) as u32
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};
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buffer[y * width + x] = value;
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}
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}
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}
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fn main() {
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let event_loop = EventLoop::new();
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let window = WindowBuilder::new()
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.with_title("Press space to show/hide a rectangle")
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.build(&event_loop)
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.unwrap();
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#[cfg(target_arch = "wasm32")]
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{
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use winit::platform::web::WindowExtWebSys;
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web_sys::window()
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.unwrap()
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.document()
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.unwrap()
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.body()
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.unwrap()
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.append_child(&window.canvas())
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.unwrap();
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}
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let context = unsafe { softbuffer::Context::new(&window) }.unwrap();
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let mut surface = unsafe { softbuffer::Surface::new(&context, &window) }.unwrap();
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let mut flag = false;
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event_loop.run(move |event, _, control_flow| {
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*control_flow = ControlFlow::Wait;
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match event {
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Event::RedrawRequested(window_id) if window_id == window.id() => {
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// Grab the window's client area dimensions
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let (width, height) = {
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let size = window.inner_size();
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(size.width, size.height)
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};
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// Resize surface if needed
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surface
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.resize(
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NonZeroU32::new(width).unwrap(),
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NonZeroU32::new(height).unwrap(),
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)
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.unwrap();
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// Draw something in the window
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let mut buffer = surface.buffer_mut().unwrap();
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redraw(&mut buffer, width as usize, height as usize, flag);
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buffer.present().unwrap();
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}
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Event::WindowEvent {
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event: WindowEvent::CloseRequested,
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window_id,
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} if window_id == window.id() => {
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*control_flow = ControlFlow::Exit;
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}
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Event::WindowEvent {
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event:
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WindowEvent::KeyboardInput {
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input:
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KeyboardInput {
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state: ElementState::Pressed,
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virtual_keycode: Some(VirtualKeyCode::Space),
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..
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},
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..
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},
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window_id,
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} if window_id == window.id() => {
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// Flip the rectangle flag and request a redraw to show the changed image
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flag = !flag;
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window.request_redraw();
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}
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_ => {}
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}
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});
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}
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