1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

use std::error::Error as StdError;
use std::fmt;
use std::sync::Arc;
use vulkano::buffer::{BufferAccess, CpuAccessibleBuffer};
use vulkano::buffer::cpu_access::{
    ReadLock,
    WriteLock,
    ReadLockError,
    WriteLockError
};
use framing::Image;

/// Wraps a buffer, providing functions that allow the user to interpret it as
/// a frame instead of as a bunch of pixels.
#[derive(Clone, Debug)]
pub struct Buffer<T> {
    inner: Arc<CpuAccessibleBuffer<[T]>>,
    width: usize,
    height: usize
}

impl<T> Buffer<T> where T: Send + Sync + 'static {
    /// Creates the wrapper.
    ///
    /// Expects a width and height in pixels, and a buffer of length
    /// `width * height`. A buffer of incorrect length will cause a `BadLength`
    /// error to be returned.
    pub fn new(
        inner: Arc<CpuAccessibleBuffer<[T]>>,
        width: usize,
        height: usize
    ) -> Result<Self, BadLength> {
        let expected_len = width * height;
        let actual_len = inner.len();

        if expected_len == actual_len {
            Ok(Self {
                inner,
                width,
                height
            })
        } else {
            Err(BadLength {
                expected_len,
                actual_len
            })
        }
    }
}

impl<T: 'static> Buffer<T> {
    /// Try to get a read-only frame from the buffer.
    pub fn read(&self) -> Result<Reader<T>, ReadLockError> {
        let inner = self.inner.read()?;
        let (width, height) = (self.width, self.height);
        Ok(Reader { inner, width, height })
    }

    /// Try to get a mutable frame from the buffer.
    pub fn write(&self) -> Result<Writer<T>, WriteLockError> {
        let inner = self.inner.write()?;
        let (width, height) = (self.width, self.height);
        Ok(Writer { inner, width, height })
    }
}

impl<T> Buffer<T> {
    /// Get back the underlying buffer.
    pub fn buffer(&self) -> &Arc<CpuAccessibleBuffer<[T]>> {
        &self.inner
    }

    /// The width of the image, in pixels.
    pub fn width(&self) -> usize { self.width }

    /// The height of the image, in pixels.
    pub fn height(&self) -> usize { self.height }
}

/// A read-only frame.
pub struct Reader<'a, T: 'a> {
    inner: ReadLock<'a, [T]>,
    width: usize,
    height: usize
}

impl<'a, T: 'a> Image for Reader<'a, T> where T: Clone {
    type Pixel = T;

    fn width(&self) -> usize { self.width }
    fn height(&self) -> usize { self.height }

    unsafe fn pixel(&self, x: usize, y: usize) -> Self::Pixel {
        self.inner.get_unchecked(y * self.width + x).clone()
    }
}

impl<'a, T: 'a> AsRef<[T]> for Reader<'a, T> {
    fn as_ref(&self) -> &[T] {
        &self.inner
    }
}

/// A mutable frame.
pub struct Writer<'a, T: 'a> {
    inner: WriteLock<'a, [T]>,
    width: usize,
    height: usize
}

impl<'a, T: 'a> Image for Writer<'a, T> where T: Clone {
    type Pixel = T;

    fn width(&self) -> usize { self.width }
    fn height(&self) -> usize { self.height }

    unsafe fn pixel(&self, x: usize, y: usize) -> Self::Pixel {
        self.inner.get_unchecked(y * self.width + x).clone()
    }
}

impl<'a, T: 'a> AsRef<[T]> for Writer<'a, T> {
    fn as_ref(&self) -> &[T] {
        &self.inner
    }
}

impl<'a, T: 'a> AsMut<[T]> for Writer<'a, T> {
    fn as_mut(&mut self) -> &mut [T] {
        &mut self.inner
    }
}

/// A struct representing a buffer length mismatch.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct BadLength {
    expected_len: usize,
    actual_len: usize
}

impl fmt::Display for BadLength {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "the buffer had to have {} pixels, but had {} pixels",
            self.expected_len,
            self.actual_len
        )
    }
}

impl StdError for BadLength {
    fn description(&self) -> &str {
        "incorrect buffer length"
    }
}