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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*!
# glam

`glam` is a simple and fast linear algebra library for games and graphics.

## Features

`glam` is built with SIMD in mind. Currently only SSE2 on x86/x86_64 is
supported as this is what stable Rust supports.

* Vector, quaternion and matrix types support for [`f32`](mod@f32) and [`f64`](mod@f64)
* Vector types supported for [`i32`](mod@i32), [`u32`](mod@u32) and [`bool`](mod@bool)
* SSE2 storage and optimization for many [`f32`](mod@f32) types, including [`Mat2`], [`Mat4`],
  [`Quat`], [`Vec3A`] and [`Vec4`]
* Scalar math fallback implementations exist when SSE2 is not available
* Most functionality includes unit tests and benchmarks

## Linear algebra conventions

`glam` interprets vectors as column matrices (also known as "column vectors")
meaning when transforming a vector with a matrix the matrix goes on the left.

```
use glam::{Mat3, Vec3};
let m = Mat3::IDENTITY;
let x = Vec3::X;
let v = m * x;
assert_eq!(v, x);
```

Matrices are stored in memory in column-major order.

## Direct element access

Because some types may internally be implemeted using SIMD types, direct access to vector elements
is supported by implementing the [`Deref`] and [`DerefMut`] traits.

```
use glam::Vec3A;
let mut v = Vec3A::new(1.0, 2.0, 3.0);
assert_eq!(3.0, v.z);
v.z += 1.0;
assert_eq!(4.0, v.z);
```

[`Deref`]: https://doc.rust-lang.org/std/ops/trait.Deref.html
[`DerefMut`]: https://doc.rust-lang.org/std/ops/trait.DerefMut.html

## Size and alignment of types

Some `glam` types use SIMD for storage meaning they are 16 byte aligned, these
types include [`Mat2`], [`Mat4`], [`Quat`], [`Vec3A`] and [`Vec4`].

When SSE2 is not available on the target architecture this type will still be 16
byte aligned so that object sizes and layouts will not change between
architectures.

SIMD support can be disabled entirely using the `scalar-math` feature. This
feature will also disable SIMD alignment meaning most types will use native
`f32` alignment of 4 bytes.

All the main `glam` types are `#[repr(C)]`, so they are possible to expose as
struct members to C interfaces if desired. Be mindful of Vec3A's extra padding
though.

## Vec3A

[`Vec3A`] is a SIMD optimized version of the [`Vec3`] type, which due to 16 byte
alignment results in [`Vec3A`] containing 4 bytes of padding making it 16 bytes
in size in total.

| Type    | `f32` bytes | Align bytes | Padding | Size bytes |
|:--------|------------:|------------:|--------:|-----------:|
|[`Vec3`] |           12|            4|        0|          12|
|[`Vec3A`]|           12|           16|        4|          16|

Despite this wasted space the SIMD version tends to outperform the `f32`
implementation in [**mathbench**](https://github.com/bitshifter/mathbench-rs)
benchmarks.

`glam` treats [`Vec3`] as the default vector 3 type and [`Vec3A`] a special case for
optimization. When methods need to return a vector 3 type they will generally
return [`Vec3`].

There are [`From`] trait implementations for converting from [`Vec4`] to a [`Vec3A`]
and between [`Vec3`] and [`Vec3A`] (and vice versa).
```
use glam::{Vec3, Vec3A, Vec4};

let v4 = Vec4::new(1.0, 2.0, 3.0, 4.0);

// Convert from `Vec4` to `Vec3A`, this is a no-op if SIMD is supported.
let v3a = Vec3A::from(v4);
assert_eq!(Vec3A::new(1.0, 2.0, 3.0), v3a);

// Convert from `Vec3A` to `Vec3`.
let v3 = Vec3::from(v3a);
assert_eq!(Vec3::new(1.0, 2.0, 3.0), v3);

// Convert from `Vec3` to `Vec3A`.
let v3a = Vec3A::from(v3);
assert_eq!(Vec3A::new(1.0, 2.0, 3.0), v3a);
```

## Vector swizzles

`glam` vector types have functions allowing elements of vectors to be reordered,
this includes creating a vector of a different size from the vectors elements.

The swizzle functions are implemented using traits to add them to each vector
type. This is primarily because there are a lot of swizzle functions which can
obfuscate the other vector functions in documentation and so on. The traits are
[`Vec2Swizzles`], [`Vec3Swizzles`] and [`Vec4Swizzles`].

Note that the [`Vec3Swizzles`] implementation for [`Vec3A`] will return a [`Vec3A`]
for 3 element swizzles, all other implementations will return [`Vec3`].

```
use glam::{swizzles::*, Vec2, Vec3, Vec3A, Vec4};

let v = Vec4::new(1.0, 2.0, 3.0, 4.0);

// Reverse elements of `v`, if SIMD is supported this will use a vector shuffle.
let wzyx = v.wzyx();
assert_eq!(Vec4::new(4.0, 3.0, 2.0, 1.0), wzyx);

// Swizzle the yzw elements of `v` into a `Vec3`
let yzw = v.yzw();
assert_eq!(Vec3::new(2.0, 3.0, 4.0), yzw);

// To swizzle a `Vec4` into a `Vec3A` swizzle the `Vec4` first then convert to
// `Vec3A`. If SIMD is supported this will use a vector shuffle. The last
// element of the shuffled `Vec4` is ignored by the `Vec3A`.
let yzw = Vec3A::from(v.yzwx());
assert_eq!(Vec3A::new(2.0, 3.0, 4.0), yzw);

// You can swizzle from a `Vec4` to a `Vec2`
let xy = v.xy();
assert_eq!(Vec2::new(1.0, 2.0), xy);

// And back again
let yyxx = xy.yyxx();
assert_eq!(Vec4::new(2.0, 2.0, 1.0, 1.0), yyxx);
```

## SIMD and scalar consistency

`glam` types implement `serde` `Serialize` and `Deserialize` traits to ensure
that they will serialize and deserialize exactly the same whether or not
SIMD support is being used.

The SIMD versions implement the `core::fmt::Debug` and `core::fmt::Display`
traits so they print the same as the scalar version.

```
use glam::Vec4;
let a = Vec4::new(1.0, 2.0, 3.0, 4.0);
assert_eq!(format!("{}", a), "[1, 2, 3, 4]");
```

## Feature gates

All `glam` dependencies are optional, however some are required for tests
and benchmarks.

* `std` - the default feature, has no dependencies.
* `rand` - used to generate random values. Used in benchmarks.
* `serde` - used for serialization and deserialization of types.
* `mint` - used for interoperating with other linear algebra libraries.
* `scalar-math` - disables SIMD support and uses native alignment for all
  types.
* `debug-glam-assert` - adds assertions in debug builds which check the validity
  of parameters passed to `glam` to help catch runtime errors.
* `glam-assert` - adds assertions to all builds which check the validity of
  parameters passed to `glam` to help catch runtime errors.

## Minimum Supported Version or Rust (MSVR)

The minimum supported version of Rust for `glam` is `1.36.0`.

*/
#![doc(html_root_url = "https://docs.rs/glam/0.13.0")]
#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(target_arch = "spirv", feature(register_attr, repr_simd))]

#[cfg(all(target_arch = "spirv", feature = "std"))]
compile_error!("`std` feature is not supported when building for SPIRV");

#[cfg(all(target_arch = "spirv", feature = "glam-assert"))]
compile_error!("`glam-assert` feature is not supported when building for SPIRV");

#[cfg(all(target_arch = "spirv", feature = "debug-glam-assert"))]
compile_error!("`debug-glam-assert` feature is not supported when building for SPIRV");

#[cfg(all(target_arch = "spirv", feature = "serde"))]
compile_error!("`serde` feature is not supported when building for SPIRV");

#[cfg(all(target_arch = "spirv", feature = "rand"))]
compile_error!("`rand` feature is not supported when building for SPIRV");

#[cfg(all(target_arch = "spirv", feature = "bytemuck"))]
compile_error!("`bytemuck` feature is not supported when building for SPIRV");

#[macro_use]
mod macros;
#[macro_use]
mod vec;

#[doc(hidden)]
pub mod cast;

mod core;
mod mat2;
mod mat3;
mod mat4;
mod quat;
mod vec2;
mod vec3;
mod vec4;
mod vec_mask;

mod features;

#[cfg(feature = "transform-types")]
mod transform;

#[doc(hidden)]
pub use self::core::storage::{XY, XYZ, XYZW};

/** `bool` vector mask types. */
pub mod bool {
    pub use super::vec_mask::{BVec2, BVec3, BVec3A, BVec4, BVec4A};
}
pub use self::bool::*;

/** `f32` vector, quaternion and matrix types. */
pub mod f32 {
    // pub use super::cast::{
    //     F32x16Cast, F32x9Cast, Mat2Cast, Mat3Cast, Mat4Cast, Vec2Cast, Vec3Cast, Vec4Cast,
    // };
    pub use super::mat2::{mat2, Mat2};
    pub use super::mat3::{mat3, Mat3};
    pub use super::mat4::{mat4, Mat4};
    pub use super::quat::{quat, Quat};
    pub use super::vec2::{vec2, Vec2};
    pub use super::vec3::{vec3, vec3a, Vec3, Vec3A};
    pub use super::vec4::{vec4, Vec4};

    #[cfg(feature = "transform-types")]
    pub use super::transform::{TransformRT, TransformSRT};
}
pub use self::f32::*;

/** `f64` vector, quaternion and matrix types. */
pub mod f64 {
    // pub use super::cast::{
    //     DMat2Cast, DMat3Cast, DMat4Cast, DVec2Cast, DVec3Cast, DVec4Cast, F64x16Cast, F64x9Cast,
    // };
    pub use super::mat2::{dmat2, DMat2};
    pub use super::mat3::{dmat3, DMat3};
    pub use super::mat4::{dmat4, DMat4};
    pub use super::quat::{dquat, DQuat};
    pub use super::vec2::{dvec2, DVec2};
    pub use super::vec3::{dvec3, DVec3};
    pub use super::vec4::{dvec4, DVec4};
}
pub use self::f64::*;

/** `i32` vector types. */
pub mod i32 {
    // pub use super::cast::{
    //     IVec2Cast, IVec3Cast, IVec4Cast,
    // };
    pub use super::vec2::{ivec2, IVec2};
    pub use super::vec3::{ivec3, IVec3};
    pub use super::vec4::{ivec4, IVec4};
}
pub use self::i32::*;

/** `u32` vector types. */
pub mod u32 {
    // pub use super::cast::{
    //     UVec2Cast, UVec3Cast, UVec4Cast,
    // };
    pub use super::vec2::{uvec2, UVec2};
    pub use super::vec3::{uvec3, UVec3};
    pub use super::vec4::{uvec4, UVec4};
}
pub use self::u32::*;

/** Traits adding swizzle methods to all vector types. */
pub mod swizzles;

pub use self::swizzles::{Vec2Swizzles, Vec3Swizzles, Vec4Swizzles};