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
|
use crate::vk;
use std::iter::Iterator;
use std::marker::PhantomData;
use std::mem::size_of;
use std::os::raw::c_void;
use std::{io, slice};
/// [`Align`] handles dynamic alignment. The is useful for dynamic uniform buffers where
/// the alignment might be different. For example a 4x4 f32 matrix has a size of 64 bytes
/// but the min alignment for a dynamic uniform buffer might be 256 bytes. A slice of `&[Mat4x4<f32>]`
/// has a memory layout of `[[64 bytes], [64 bytes], [64 bytes]]`, but it might need to have a memory
/// layout of `[[256 bytes], [256 bytes], [256 bytes]]`.
/// [`Align::copy_from_slice`] will copy a slice of `&[T]` directly into the host memory without
/// an additional allocation and with the correct alignment.
#[derive(Debug, Clone)]
pub struct Align<T> {
ptr: *mut c_void,
elem_size: vk::DeviceSize,
size: vk::DeviceSize,
_m: PhantomData<T>,
}
#[derive(Debug)]
pub struct AlignIter<'a, T: 'a> {
align: &'a mut Align<T>,
current: vk::DeviceSize,
}
impl<T: Copy> Align<T> {
pub fn copy_from_slice(&mut self, slice: &[T]) {
use std::slice::from_raw_parts_mut;
if self.elem_size == size_of::<T>() as u64 {
unsafe {
let mapped_slice = from_raw_parts_mut(self.ptr.cast(), slice.len());
mapped_slice.copy_from_slice(slice);
}
} else {
for (i, val) in self.iter_mut().enumerate().take(slice.len()) {
*val = slice[i];
}
}
}
}
fn calc_padding(adr: vk::DeviceSize, align: vk::DeviceSize) -> vk::DeviceSize {
(align - adr % align) % align
}
impl<T> Align<T> {
pub unsafe fn new(ptr: *mut c_void, alignment: vk::DeviceSize, size: vk::DeviceSize) -> Self {
let padding = calc_padding(size_of::<T>() as vk::DeviceSize, alignment);
let elem_size = size_of::<T>() as vk::DeviceSize + padding;
assert!(calc_padding(size, alignment) == 0, "size must be aligned");
Self {
ptr,
elem_size,
size,
_m: PhantomData,
}
}
pub fn iter_mut(&mut self) -> AlignIter<T> {
AlignIter {
current: 0,
align: self,
}
}
}
impl<'a, T: Copy + 'a> Iterator for AlignIter<'a, T> {
type Item = &'a mut T;
fn next(&mut self) -> Option<Self::Item> {
if self.current == self.align.size {
return None;
}
unsafe {
// Need to cast to *mut u8 because () has size 0
let ptr = (self.align.ptr.cast::<u8>())
.offset(self.current as isize)
.cast();
self.current += self.align.elem_size;
Some(&mut *ptr)
}
}
}
/// Decode SPIR-V from bytes.
///
/// This function handles SPIR-V of arbitrary endianness gracefully, and returns correctly aligned
/// storage.
///
/// # Examples
/// ```no_run
/// // Decode SPIR-V from a file
/// let mut file = std::fs::File::open("/path/to/shader.spv").unwrap();
/// let words = ash::util::read_spv(&mut file).unwrap();
/// ```
/// ```
/// // Decode SPIR-V from memory
/// const SPIRV: &[u8] = &[
/// // ...
/// # 0x03, 0x02, 0x23, 0x07,
/// ];
/// let words = ash::util::read_spv(&mut std::io::Cursor::new(&SPIRV[..])).unwrap();
/// ```
pub fn read_spv<R: io::Read + io::Seek>(x: &mut R) -> io::Result<Vec<u32>> {
// TODO use stream_len() once it is stabilized and remove the subsequent rewind() call
let size = x.seek(io::SeekFrom::End(0))?;
x.rewind()?;
if size % 4 != 0 {
return Err(io::Error::new(
io::ErrorKind::InvalidData,
"input length not divisible by 4",
));
}
if size > usize::max_value() as u64 {
return Err(io::Error::new(io::ErrorKind::InvalidData, "input too long"));
}
let words = (size / 4) as usize;
// https://github.com/MaikKlein/ash/issues/354:
// Zero-initialize the result to prevent read_exact from possibly
// reading uninitialized memory.
let mut result = vec![0u32; words];
x.read_exact(unsafe {
slice::from_raw_parts_mut(result.as_mut_ptr().cast::<u8>(), words * 4)
})?;
const MAGIC_NUMBER: u32 = 0x0723_0203;
if !result.is_empty() && result[0] == MAGIC_NUMBER.swap_bytes() {
for word in &mut result {
*word = word.swap_bytes();
}
}
if result.is_empty() || result[0] != MAGIC_NUMBER {
return Err(io::Error::new(
io::ErrorKind::InvalidData,
"input missing SPIR-V magic number",
));
}
Ok(result)
}
|
