glium 0.32.1

Elegant and safe OpenGL wrapper. Glium is an intermediate layer between OpenGL and your application. You still need to manually handle the graphics pipeline, but without having to use OpenGL's old and error-prone API. Its objectives: - Be safe to use. Many aspects of OpenGL that can trigger a crash if misused are automatically handled by glium. - Provide an API that enforces good pratices such as RAII or stateless function calls. - Be compatible with all OpenGL versions that support shaders, providing unified API when things diverge. - Avoid all OpenGL errors beforehand. - Produce optimized OpenGL function calls, and allow the user to easily use modern OpenGL techniques.
Documentation 
/*!
Pixel buffers are buffers that contain two-dimensional texture data.

Contrary to textures, pixel buffers are stored in a client-defined format. They are used
to transfer data to or from the video memory, before or after being turned into a texture.
*/
use std::borrow::Cow;
use std::cell::Cell;
use std::ops::{Deref, DerefMut};

use crate::backend::Facade;

use crate::GlObject;
use crate::buffer::{ReadError, Buffer, BufferType, BufferMode};
use crate::gl;

use crate::texture::PixelValue;
use crate::texture::Texture2dDataSink;

/// Buffer that stores the content of a texture.
///
/// The generic type represents the type of pixels that the buffer contains.
pub struct PixelBuffer<T> where T: PixelValue {
    buffer: Buffer<[T]>,
    dimensions: Cell<Option<(u32, u32)>>,
}

impl<T> PixelBuffer<T> where T: PixelValue {
    /// Builds a new buffer with an uninitialized content.
    #[inline]
    pub fn new_empty<F: ?Sized>(facade: &F, capacity: usize) -> PixelBuffer<T> where F: Facade {
        PixelBuffer {
            buffer: Buffer::empty_array(facade, BufferType::PixelPackBuffer, capacity,
                                            BufferMode::Default).unwrap(),
            dimensions: Cell::new(None),
        }
    }

    /// Reads the content of the pixel buffer.
    #[inline]
    pub fn read_as_texture_2d<S>(&self) -> Result<S, ReadError> where S: Texture2dDataSink<T> {
        let dimensions = self.dimensions.get().expect("The pixel buffer is empty");
        let data = self.read()?;
        Ok(S::from_raw(Cow::Owned(data), dimensions.0, dimensions.1))
    }
}

impl<T> Deref for PixelBuffer<T> where T: PixelValue {
    type Target = Buffer<[T]>;

    #[inline]
    fn deref(&self) -> &Buffer<[T]> {
        &self.buffer
    }
}

impl<T> DerefMut for PixelBuffer<T> where T: PixelValue {
    #[inline]
    fn deref_mut(&mut self) -> &mut Buffer<[T]> {
        &mut self.buffer
    }
}

// TODO: rework this
impl<T> GlObject for PixelBuffer<T> where T: PixelValue {
    type Id = gl::types::GLuint;

    #[inline]
    fn get_id(&self) -> gl::types::GLuint {
        self.buffer.get_id()
    }
}

// TODO: remove this hack
#[doc(hidden)]
#[inline]
pub fn store_infos<T>(b: &PixelBuffer<T>, dimensions: (u32, u32)) where T: PixelValue {
    b.dimensions.set(Some(dimensions));
}