edgefirst_gbm/
surface.rs

1use crate::{AsRaw, BufferObject, Gbm, Ptr};
2use std::{error, fmt, marker::PhantomData, sync::Arc};
3
4/// A GBM rendering surface
5pub struct Surface<T: 'static> {
6    // Declare `ffi` first so it is dropped before `_device`
7    ffi: Ptr<ffi::gbm_surface>,
8    _device: Ptr<ffi::gbm_device>,
9    _bo_userdata: PhantomData<T>,
10    gbm: Arc<Gbm>,
11}
12
13impl<T: 'static> fmt::Debug for Surface<T> {
14    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
15        f.debug_struct("Surface")
16            .field("ptr", &format_args!("{:p}", &self.ffi))
17            .field("device", &format_args!("{:p}", &self._device))
18            .finish()
19    }
20}
21
22/// Errors that may happen when locking the front buffer
23#[derive(Debug, Clone, Copy, PartialEq, Eq)]
24pub struct FrontBufferError;
25
26impl fmt::Display for FrontBufferError {
27    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
28        write!(f, "Unknown error")
29    }
30}
31
32impl error::Error for FrontBufferError {}
33
34impl<T: 'static> Surface<T> {
35    ///  Return whether or not a surface has free (non-locked) buffers
36    ///
37    /// Before starting a new frame, the surface must have a buffer
38    /// available for rendering.  Initially, a GBM surface will have a free
39    /// buffer, but after one or more buffers
40    /// [have been locked](Self::lock_front_buffer()),
41    /// the application must check for a free buffer before rendering.
42    pub fn has_free_buffers(&self) -> bool {
43        unsafe { self.gbm.gbm_surface_has_free_buffers(*self.ffi) != 0 }
44    }
45
46    /// Lock the surface's current front buffer
47    ///
48    /// Locks rendering to the surface's current front buffer and returns
49    /// a handle to the underlying [`BufferObject`].
50    ///
51    /// If an error occurs a [`FrontBufferError`] is returned.
52    ///
53    /// # Safety
54    /// This function must be called exactly once after calling
55    /// `eglSwapBuffers`.  Calling it before any `eglSwapBuffers` has happened
56    /// on the surface or two or more times after `eglSwapBuffers` is an
57    /// error and may cause undefined behavior.
58    pub unsafe fn lock_front_buffer(&self) -> Result<BufferObject<T>, FrontBufferError> {
59        let buffer_ptr = self.gbm.gbm_surface_lock_front_buffer(*self.ffi);
60        if !buffer_ptr.is_null() {
61            let surface_ptr = self.ffi.clone();
62            let gbm_ = self.gbm.clone();
63            let buffer = BufferObject {
64                ffi: Ptr::new(buffer_ptr, move |ptr| {
65                    gbm_.gbm_surface_release_buffer(*surface_ptr, ptr);
66                }),
67                _device: self._device.clone(),
68                _userdata: std::marker::PhantomData,
69                gbm: self.gbm.clone(),
70            };
71            Ok(buffer)
72        } else {
73            Err(FrontBufferError)
74        }
75    }
76
77    pub(crate) unsafe fn new(
78        ffi: *mut ffi::gbm_surface,
79        device: Ptr<ffi::gbm_device>,
80        gbm: Arc<Gbm>,
81    ) -> Surface<T> {
82        let gbm_ = gbm.clone();
83        Surface {
84            ffi: Ptr::new(ffi, move |ptr| gbm_.gbm_surface_destroy(ptr)),
85            _device: device,
86            _bo_userdata: PhantomData,
87            gbm,
88        }
89    }
90}
91
92impl<T: 'static> AsRaw<ffi::gbm_surface> for Surface<T> {
93    fn as_raw(&self) -> *const ffi::gbm_surface {
94        *self.ffi
95    }
96}
edgefirst_gbm/surface.rs

edgefirst_gbm/
surface.rs
