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// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

//! Location in memory that contains data.
//!
//! A Vulkan buffer is very similar to a buffer that you would use in programming languages in
//! general, in the sense that it is a location in memory that contains data. The difference
//! between a Vulkan buffer and a regular buffer is that the content of a Vulkan buffer is
//! accessible from the GPU.
//!
//! # Various kinds of buffers
//!
//! The low level implementation of a buffer is [`UnsafeBuffer`](sys/struct.UnsafeBuffer.html).
//! This type makes it possible to use all the features that Vulkan is capable of, but as its name
//! tells it is unsafe to use.
//!
//! Instead you are encouraged to use one of the high-level wrappers that vulkano provides. Which
//! wrapper to use depends on the way you are going to use the buffer:
//!
//! - A [`DeviceLocalBuffer`](device_local/struct.DeviceLocalBuffer.html) designates a buffer
//!   usually located in video memory and whose content can't be directly accessed by your
//!   application. Accessing this buffer from the GPU is generally faster compared to accessing a
//!   CPU-accessible buffer.
//! - An [`ImmutableBuffer`](immutable/struct.ImmutableBuffer.html) designates a buffer in video
//!   memory and whose content can only be written at creation. Compared to `DeviceLocalBuffer`,
//!   this buffer requires less CPU processing because we don't need to keep track of the reads
//!   and writes.
//! - A [`CpuBufferPool`](cpu_pool/struct.CpuBufferPool.html) is a ring buffer that can be used to
//!   transfer data between the CPU and the GPU at a high rate.
//! - A [`CpuAccessibleBuffer`](cpu_access/struct.CpuAccessibleBuffer.html) is a simple buffer that
//!   can be used to prototype. It may be removed from vulkano in the far future.
//!
//! Here is a quick way to choose which buffer to use. Do you often need to read or write
//! the content of the buffer? If so, use a `CpuBufferPool`. Otherwise, do you need to be able to
//! modify the content of the buffer after its initialization? If so, use a `DeviceLocalBuffer`.
//! If no to both questions, use an `ImmutableBuffer`.
//!
//! When deciding how your buffer is going to be used, don't forget that sometimes the best
//! solution is to manipulate multiple buffers instead. For example if you need to update a buffer's
//! content only from time to time, it may be a good idea to simply recreate a new `ImmutableBuffer`
//! every time.
//! Another example: if a buffer is under constant access by the GPU but you need to
//! read its content on the CPU from time to time, it may be a good idea to use a
//! `DeviceLocalBuffer` as the main buffer and a `CpuBufferPool` for when you need to read it.
//! Then whenever you need to read the main buffer, ask the GPU to copy from the device-local
//! buffer to the CPU buffer pool, and read the CPU buffer pool instead.
//!
//! # Buffers usage
//!
//! When you create a buffer object, you have to specify its *usage*. In other words, you have to
//! specify the way it is going to be used. Trying to use a buffer in a way that wasn't specified
//! when you created it will result in a runtime error.
//!
//! You can use buffers for the following purposes:
//!
//! - Can contain arbitrary data that can be transferred from/to other buffers and images.
//! - Can be read and modified from a shader.
//! - Can be used as a source of vertices and indices.
//! - Can be used as a source of list of models for draw indirect commands.
//!
//! Accessing a buffer from a shader can be done in the following ways:
//!
//! - As a uniform buffer. Uniform buffers are read-only.
//! - As a storage buffer. Storage buffers can be read and written.
//! - As a uniform texel buffer. Contrary to a uniform buffer, the data is interpreted by the
//!   GPU and can be for example normalized.
//! - As a storage texel buffer. Additionally, some data formats can be modified with atomic
//!   operations.
//!
//! Using uniform/storage texel buffers requires creating a *buffer view*. See the `view` module
//! for how to create a buffer view.
//!

pub use self::cpu_access::CpuAccessibleBuffer;
pub use self::cpu_pool::CpuBufferPool;
pub use self::device_local::DeviceLocalBuffer;
pub use self::immutable::ImmutableBuffer;
pub use self::slice::BufferSlice;
pub use self::sys::BufferCreationError;
pub use self::traits::BufferAccess;
pub use self::traits::BufferInner;
pub use self::traits::TypedBufferAccess;
pub use self::usage::BufferUsage;
pub use self::view::BufferView;
pub use self::view::BufferViewRef;

pub mod cpu_access;
pub mod cpu_pool;
pub mod device_local;
pub mod immutable;
pub mod sys;
pub mod view;

mod slice;
mod traits;
mod usage;