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use core::{error, fmt};
use crate::*;
/// Surface texture that can be rendered to.
/// Result of a successful call to [`Surface::get_current_texture`].
///
/// This type is unique to the Rust API of `wgpu`. In the WebGPU specification,
/// the [`GPUCanvasContext`](https://gpuweb.github.io/gpuweb/#canvas-context) provides
/// a texture without any additional information.
#[derive(Debug, Clone)]
pub struct SurfaceTexture {
/// Accessible view of the frame.
pub texture: Texture,
/// `true` if the acquired buffer can still be used for rendering,
/// but should be recreated for maximum performance.
pub suboptimal: bool,
pub(crate) presented: bool,
pub(crate) detail: dispatch::DispatchSurfaceOutputDetail,
}
#[cfg(send_sync)]
static_assertions::assert_impl_all!(SurfaceTexture: Send, Sync);
crate::cmp::impl_eq_ord_hash_proxy!(SurfaceTexture => .texture.inner);
impl SurfaceTexture {
/// Schedule this texture to be presented on the owning surface.
///
/// Needs to be called after any work on the texture is scheduled via [`Queue::submit`].
///
/// # Platform dependent behavior
///
/// On Wayland, `present` will attach a `wl_buffer` to the underlying `wl_surface` and commit the new surface
/// state. If it is desired to do things such as request a frame callback, scale the surface using the viewporter
/// or synchronize other double buffered state, then these operations should be done before the call to `present`.
pub fn present(mut self) {
self.presented = true;
self.detail.present();
}
#[cfg(custom)]
/// Returns custom implementation of SurfaceTexture (if custom backend and is internally T)
pub fn as_custom<T: crate::custom::SurfaceOutputDetailInterface>(&self) -> Option<&T> {
self.detail.as_custom()
}
}
impl Drop for SurfaceTexture {
fn drop(&mut self) {
if !self.presented && !thread_panicking() {
self.detail.texture_discard();
}
}
}
/// Result of an unsuccessful call to [`Surface::get_current_texture`].
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum SurfaceError {
/// A timeout was encountered while trying to acquire the next frame.
Timeout,
/// The underlying surface has changed, and therefore the swap chain must be updated.
Outdated,
/// The swap chain has been lost and needs to be recreated.
Lost,
/// There is no more memory left to allocate a new frame.
OutOfMemory,
/// Acquiring a texture failed with a generic error. Check error callbacks for more information.
Other,
}
static_assertions::assert_impl_all!(SurfaceError: Send, Sync);
impl fmt::Display for SurfaceError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", match self {
Self::Timeout => "A timeout was encountered while trying to acquire the next frame",
Self::Outdated => "The underlying surface has changed, and therefore the swap chain must be updated",
Self::Lost => "The swap chain has been lost and needs to be recreated",
Self::OutOfMemory => "There is no more memory left to allocate a new frame",
Self::Other => "Acquiring a texture failed with a generic error. Check error callbacks for more information",
})
}
}
impl error::Error for SurfaceError {}
fn thread_panicking() -> bool {
cfg_if::cfg_if! {
if #[cfg(std)] {
std::thread::panicking()
} else if #[cfg(panic = "abort")] {
// If `panic = "abort"` then a thread _cannot_ be observably panicking by definition.
false
} else {
// TODO: This is potentially overly pessimistic; it may be appropriate to instead allow a
// texture to not be discarded.
// Alternatively, this could _also_ be a `panic!`, since we only care if the thread is panicking
// when the surface has not been presented.
compile_error!(
"cannot determine if a thread is panicking without either `panic = \"abort\"` or `std`"
);
}
}
}