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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
// 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.

//! Device memory allocation and memory pools.
//!
//! By default, memory allocation is automatically handled by the vulkano library when you create
//! a buffer or an image. But if you want more control, you have the possibility to costumize the
//! memory allocation strategy.
//!
//! # Memory types and heaps
//!
//! A physical device is composed of one or more **memory heaps**. A memory heap is a pool of
//! memory that can be allocated.
//!
//! ```
//! // Enumerating memory heaps.
//! # let physical_device: vulkano::instance::PhysicalDevice = return;
//! for heap in physical_device.memory_heaps() {
//!     println!("Heap #{:?} has a capacity of {:?} bytes", heap.id(), heap.size());
//! }
//! ```
//!
//! However you can't allocate directly from a memory heap. A memory heap is shared amongst one or
//! multiple **memory types**, which you can allocate memory from. Each memory type has different
//! characteristics.
//!
//! A memory type may or may not be visible to the host. In other words, it may or may not be
//! directly writable by the CPU. A memory type may or may not be device-local. A device-local
//! memory type has a much quicker access time from the GPU than a non-device-local type. Note
//! that non-device-local memory types are still accessible by the device, they are just slower.
//!
//! ```
//! // Enumerating memory types.
//! # let physical_device: vulkano::instance::PhysicalDevice = return;
//! for ty in physical_device.memory_types() {
//!     println!("Memory type belongs to heap #{:?}", ty.heap().id());
//!     println!("Host-accessible: {:?}", ty.is_host_visible());
//!     println!("Device-local: {:?}", ty.is_device_local());
//! }
//! ```
//!
//! Memory types are order from "best" to "worse". In other words, the implementation prefers that
//! you use the memory types that are earlier in the list. This means that selecting a memory type
//! should always be done by enumerating them and taking the first one that matches our criterias.
//!
//! ## In practice
//!
//! In practice, desktop machines usually have two memory heaps: one that represents the RAM of
//! the CPU, and one that represents the RAM of the GPU. The CPU's RAM is host-accessible but not
//! device-local, while the GPU's RAM is not host-accessible but is device-local.
//!
//! Mobile machines usually have a single memory heap that is "equally local" to both the CPU and
//! the GPU. It is both host-accessible and device-local.
//!
//! # Allocating memory and memory pools
//!
//! Allocating memory can be done by calling `DeviceMemory::alloc()`.
//!
//! Here is an example:
//!
//! ```
//! use vulkano::memory::DeviceMemory;
//!
//! # let device: std::sync::Arc<vulkano::device::Device> = return;
//! // Taking the first memory type for the sake of this example.
//! let ty = device.physical_device().memory_types().next().unwrap();
//!
//! let alloc = DeviceMemory::alloc(device.clone(), ty, 1024).expect("Failed to allocate memory");
//!
//! // The memory is automatically free'd when `alloc` is destroyed.
//! ```
//!
//! However allocating and freeing memory is very slow (up to several hundred milliseconds
//! sometimes). Instead you are strongly encouraged to use a memory pool. A memory pool is not
//! a Vulkan concept but a vulkano concept.
//!
//! A memory pool is any object that implements the `MemoryPool` trait. You can implement that
//! trait on your own structure and then use it when you create buffers and images so that they
//! get memory from that pool. By default if you don't specify any pool when creating a buffer or
//! an image, an instance of `StdMemoryPool` that is shared by the `Device` object is used.

use std::mem;
use std::os::raw::c_void;
use std::slice;

use buffer::sys::UnsafeBuffer;
use image::sys::UnsafeImage;
use vk;

pub use self::device_memory::CpuAccess;
pub use self::device_memory::DeviceMemory;
pub use self::device_memory::MappedDeviceMemory;
pub use self::device_memory::DeviceMemoryAllocError;
pub use self::pool::MemoryPool;

mod device_memory;
pub mod pool;

/// Represents requirements expressed by the Vulkan implementation when it comes to binding memory
/// to a resource.
#[derive(Debug, Copy, Clone)]
pub struct MemoryRequirements {
    /// Number of bytes of memory required.
    pub size: usize,

    /// Alignment of the requirement buffer. The base memory address must be a multiple
    /// of this value.
    pub alignment: usize,

    /// Indicates which memory types can be used. Each bit that is set to 1 means that the memory
    /// type whose index is the same as the position of the bit can be used.
    pub memory_type_bits: u32,

    /// True if the implementation prefers to use dedicated allocations (in other words, allocate
    /// a whole block of memory dedicated to this resource alone). If the implementation doesn't
    /// support dedicated allocations, this will be false.
    ///
    /// > **Note**: As its name says, using a dedicated allocation is an optimization and not a
    /// > requirement.
    pub prefer_dedicated: bool,
}

#[doc(hidden)]
impl From<vk::MemoryRequirements> for MemoryRequirements {
    #[inline]
    fn from(reqs: vk::MemoryRequirements) -> MemoryRequirements {
        MemoryRequirements {
            size: reqs.size as usize,
            alignment: reqs.alignment as usize,
            memory_type_bits: reqs.memoryTypeBits,
            prefer_dedicated: false,
        }
    }
}

#[derive(Debug, Copy, Clone)]
pub enum DedicatedAlloc<'a> {
    None,
    Buffer(&'a UnsafeBuffer),
    Image(&'a UnsafeImage),
}

/// Trait for types of data that can be mapped.
// TODO: move to `buffer` module
pub unsafe trait Content {
    /// Builds a pointer to this type from a raw pointer.
    fn ref_from_ptr<'a>(ptr: *mut c_void, size: usize) -> Option<*mut Self>;

    /// Returns true if the size is suitable to store a type like this.
    fn is_size_suitable(usize) -> bool;

    /// Returns the size of an individual element.
    fn indiv_size() -> usize;
}

unsafe impl<T> Content for T {
    #[inline]
    fn ref_from_ptr<'a>(ptr: *mut c_void, size: usize) -> Option<*mut T> {
        if size < mem::size_of::<T>() {
            return None;
        }

        Some(ptr as *mut T)
    }

    #[inline]
    fn is_size_suitable(size: usize) -> bool {
        size == mem::size_of::<T>()
    }

    #[inline]
    fn indiv_size() -> usize {
        mem::size_of::<T>()
    }
}

unsafe impl<T> Content for [T] {
    #[inline]
    fn ref_from_ptr<'a>(ptr: *mut c_void, size: usize) -> Option<*mut [T]> {
        let ptr = ptr as *mut T;
        let size = size / mem::size_of::<T>();
        Some(unsafe { slice::from_raw_parts_mut(&mut *ptr, size) as *mut [T] })
    }

    #[inline]
    fn is_size_suitable(size: usize) -> bool {
        size % mem::size_of::<T>() == 0
    }

    #[inline]
    fn indiv_size() -> usize {
        mem::size_of::<T>()
    }
}

/*
TODO: do this when it's possible
unsafe impl Content for .. {}
impl<'a, T> !Content for &'a T {}
impl<'a, T> !Content for &'a mut T {}
impl<T> !Content for *const T {}
impl<T> !Content for *mut T {}
impl<T> !Content for Box<T> {}
impl<T> !Content for UnsafeCell<T> {}

*/