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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.

    //! Provides a way for shaders to access the content of buffers and images, or read arbitrary data.
    //!
    //! If you except vertex attributes, there are two ways in Vulkan to pass data to a shader:
    //!
    //! - You can pass a very small amount of data (only a guaranteed 128 bytes) through the *push
    //!   constants* mechanism. Push constants are the fastest and easiest way to pass data.
    //! - You can make your shader read from a buffer or an image by binding it to a *descriptor*.
    //!
    //! Here is an example fragment shader in GLSL that uses both:
    //!
    //! ```ignore
    //! #version 450
    //!
    //! // This is a descriptor that contains a texture.
    //! layout(set = 0, binding = 0) uniform sampler2D u_texture;
    //!
    //! // This is a descriptor that contains a buffer.
    //! layout(set = 0, binding = 1) uniform struct {
    //!     int data[128];
    //! } u_buffer;
    //!
    //! layout(push_constant) uniform PushConstants {
    //!     // This is a push constant.
    //!     float opacity;
    //! } push_constants;
    //!
    //! layout(location = 0) in vec2 v_tex_coords;
    //! layout(location = 0) out vec4 f_output;
    //!
    //! void main() {
    //!     f_output.rgb = texture(u_texture, v_tex_coords).rgb;
    //!     if (u_buffer.data[12] == 5) { f_output.rgb *= 2.0; }
    //!     f_output.a = push_constants.opacity;
    //! }
    //! ```
    //!
    //! # Descriptors
    //!
    //! In order to read the content of a buffer or an image from a shader, that buffer or image
    //! must be put in a *descriptor*. Each descriptor contains one buffer or one image alongside with
    //! the way that it can be accessed. A descriptor can also be an array, in which case it contains
    //! multiple buffers or images that all have the same layout.
    //!
    //! Descriptors are grouped in what is called *descriptor sets*. In Vulkan you don't bind
    //! individual descriptors one by one, but you create then bind descriptor sets one by one. As
    //! binding a descriptor set has (small but non-null) a cost, you are encouraged to put descriptors
    //! that are often used together in the same set so that you can keep the same set binding through
    //! multiple draws.
    //!
    //! # Example
    //!
    //! > **Note**: This section describes the simple way to bind resources. There are more optimized
    //! > ways.
    //!
    //! There are two steps to give access to a resource in a shader: creating the descriptor set, and
    //! passing the descriptor sets when drawing.
    //!
    //! ## Creating a descriptor set
    //!
    //! ```ignore
    //! // TODO: write example for: PersistentDescriptorSet::start(pipeline.clone(), 0).add_buffer(data_buffer.clone())
    //! ```
    //!
    //! ## Passing the descriptor set when drawing
    //!
    //! TODO: write
    //!
    //! # When drawing
    //!
    //! When you call a function that adds a draw command to a command buffer, one of the parameters
    //! corresponds to the list of descriptor sets to use, and another parameter contains the push
    //! constants. Vulkano will check that what you passed is compatible with the layout of the
    //! compute or graphics pipeline.
    //!
    //! TODO: talk about perfs of changing sets

    pub use self::descriptor_set::DescriptorSet;
    pub use self::pipeline_layout::PipelineLayoutAbstract;

    pub mod descriptor;
    pub mod descriptor_set;
    pub mod pipeline_layout;

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