[−][src]Crate std140
This module contains types that may be used to define Rust struct types that match the GLSL std140 memory layout.
Std140 is a standardized memory layout for GLSL shader interface blocks (e.g. uniform blocks). An interface block is a group op typed GLSL variables. For details on the layout rules for std140, please refer to the section 2.12.6.4 "Standard Uniform Block Layout" of the OpenGL ES 3.0 Specification.
This module aims to make it easy to construct and manipulate a block of std140 compatible memory
as a Rust struct, such that the struct's memory layout will match a GLSL interface block if
every block member is pairwise type-compatible with the struct field in the corresponding
position. Position here relates to the order in which block members and struct fields are
declared, e.g.: the 1st block member must be compatible with the 1st struct field, the 2nd block
member must be compatible with the 2nd struct field, etc. The struct itself has to be marked
with the #[repr_std140]
attribute: this ensures the rust compiler will
correctly order and align the fields.
For GLSL primitive types, compatibility is defined by the following mapping from GLSL types to
std140
types:
float
: floatvec2
: vec2vec3
: vec3vec4
: vec4mat2
: mat2x2mat3
: mat3x3mat4
: mat4x4mat2x2
: mat2x2mat2x3
: mat2x3mat2x4
: mat2x4mat3x2
: mat3x2mat3x3
: mat3x3mat3x4
: mat3x4mat4x2
: mat4x2mat4x3
: mat4x3mat4x4
: mat4x4int
: intivec2
: ivec2ivec3
: ivec3ivec4
: ivec4uint
: uintuvec2
: uvec2uvec3
: uvec3uvec4
: uvec4bool
: booleanbvec2
: bvec2bvec3
: bvec3bvec4
: bvec4
A GLSL struct type is compatible with a field if this field's type is a Rust struct marked with
#[repr_std140]
and this struct's fields are pair-wise compatible with the GLSL
struct field in the corresponding position.
A GLSL array of GLSL type T
with compatible type T_c
(as defined above) and length N
is
compatible with a field of type std140::array<T_c, N>
.
Example
Given the following GLSL declaration of an (uniform) interface block:
struct PointLight {
vec3 position;
float intensity;
}
layout(std140) uniform Uniforms {
mat4 transform;
vec3 ambient_light_color;
PointLight lights[2];
}
The following will produce a Rust struct instance with a compatible memory layout:
// This library relies on the `const_generics` feature to represent std140 arrays. If your // types have array fields, then this feature needs to be enabled. #![feature(const_generics)] #[std140::repr_std140] struct PointLight { position: std140::vec3, intensity: std140::float, } #[std140::repr_std140] struct Uniforms { transform: std140::mat4x4, ambient_light_color: std140::vec3, lights: std140::array<PointLight, 2> } let instance = Uniforms { transform: std140::mat4x4( std140::vec4(1.0, 0.0, 0.0, 0.0), std140::vec4(0.0, 1.0, 0.0, 0.0), std140::vec4(0.0, 0.0, 1.0, 0.0), std140::vec4(0.0, 0.0, 0.0, 1.0), ), ambient_light_color: std140::vec3(0.2, 0.2, 0.2), lights: std140::array![ PointLight { position: std140::vec3(10.0, 0.0, 10.0), intensity: std140::float(0.5) }, PointLight { position: std140::vec3(0.0, 10.0, 10.0), intensity: std140::float(0.8) }, ] };
Note that although the field names match the block member names in this example, this is not strictly necessary: only pairwise field-type compatibility is required.
Macros
array | Initializes a |
Structs
array | Represents an std140 compatible array. |
bvec2 | A column vector of 2 boolean values. |
bvec3 | A column vector of 3 boolean values. |
bvec4 | A column vector of 4 boolean values. |
float | A 32-bit floating point value. |
int | A 32-bit signed integer value. |
ivec2 | A column vector of 2 int values. |
ivec3 | A column vector of 3 int values. |
ivec4 | A column vector of 4 int values. |
mat2x2 | A matrix with 2 columns and 2 rows, represented by 2 vec2 vectors. |
mat2x3 | A matrix with 2 columns and 3 rows, represented by 2 vec3 vectors. |
mat2x4 | A matrix with 2 columns and 4 rows, represented by 2 vec4 vectors. |
mat3x2 | A matrix with 3 columns and 2 rows, represented by 3 vec2 vectors. |
mat3x3 | A matrix with 3 columns and 3 rows, represented by 3 vec3 vectors. |
mat3x4 | A matrix with 3 columns and 4 rows, represented by 3 vec4 vectors. |
mat4x2 | A matrix with 4 columns and 2 rows, represented by 4 vec2 vectors. |
mat4x3 | A matrix with 4 columns and 3 rows, represented by 4 vec3 vectors. |
mat4x4 | A matrix with 4 columns and 4 rows, represented by 4 vec4 vectors. |
uint | A 32-bit unsigned integer value. |
uvec2 | A column vector of 2 uint values. |
uvec3 | A column vector of 3 uint values. |
uvec4 | A column vector of 4 uint values. |
vec2 | A column vector of 2 float values. |
vec3 | A column vector of 3 float values. |
vec4 | A column vector of 4 float values. |
Enums
boolean | A 32-bit boolean value. |
Traits
ReprStd140 | Marker trait for types that can be used as fields in structs marked with
|
Std140ArrayElement | Marker trait for types that can be used as the element type for std140 arrays. |
Std140Struct | Marker trait for struct types that were marked with |
Functions
mat2x2 | Initializes a mat2x2 |
mat2x3 | Initializes a mat2x3 |
mat2x4 | Initializes a mat2x4 |
mat3x2 | Initializes a mat3x2 |
mat3x3 | Initializes a mat3x3 |
mat3x4 | Initializes a mat3x4 |
mat4x2 | Initializes a mat4x2 |
mat4x3 | Initializes a mat4x3 |
mat4x4 | Initializes a mat4x4 |
Attribute Macros
repr_std140 | Attribute macro that can be applied to a struct to ensure its representation is compatible with the std140 memory layout convention. |