Crate vulkano_shaders

The procedural macro for vulkano’s shader system. Manages the compile-time compilation of GLSL into SPIR-V and generation of associated Rust code.

Basic usage

mod vs {
    vulkano_shaders::shader! {
        ty: "vertex",
        src: r"
            #version 450

            layout(location = 0) in vec3 position;

            void main() {
                gl_Position = vec4(position, 1.0);
            }
        ",
    }
}

Details

If you want to take a look at what the macro generates, your best option is to use cargo-expand to view the expansion of the macro in your own code. On the other hand, if you are looking for a high-level overview, you can see the below section.

Generated code overview

The macro generates the following items of interest:

• The load constructor. This function takes an Arc<Device>, constructs a ShaderModule with the passed-in device and the shader data provided via the macro, and returns Result<Arc<ShaderModule>, Validated<VulkanError>>. Before doing so, it checks every capability instruction in the shader data, verifying that the passed-in Device has the appropriate features enabled.
• If the shaders option is used, then instead of one load constructor, there is one for each shader. They are named based on the provided names, load_first, load_second etc.
• A Rust struct translated from each struct contained in the shader data. By default, each structure has a Clone and a Copy implementation. This behavior could be customized through the custom_derives macro option (see below for details). Each struct also has an implementation of BufferContents, so that it can be read from/written to a buffer.

All of these generated items will be accessed through the module where the macro was invoked. If you wanted to store the ShaderModule in a struct of your own, you could do something like this:

// ...various use statements...
// ...`vs` module containing a `shader!` call...

pub struct Shaders {
    pub vs: Arc<ShaderModule>,
}

impl Shaders {
    pub fn load(device: Arc<Device>) -> Result<Self, Validated<VulkanError>> {
        Ok(Self {
            vs: vs::load(device)?,
        })
    }
}

Options

The options available are in the form of the following fields:

ty: "..."

This defines what shader type the given GLSL source will be compiled into. The type can be any of the following:

• vertex
• tess_ctrl
• tess_eval
• geometry
• task
• mesh
• fragment
• compute
• raygen
• anyhit
• closesthit
• miss
• intersection
• callable

For details on what these shader types mean, see Vulkano’s documentation.

src: "..."

Provides the raw GLSL source to be compiled in the form of a string. Cannot be used in conjunction with the path or bytes field.

path: "..."

Provides the path to the GLSL source to be compiled, relative to your Cargo.toml. Cannot be used in conjunction with the src or bytes field.

bytes: "..."

Provides the path to precompiled SPIR-V bytecode, relative to your Cargo.toml. Cannot be used in conjunction with the src or path field, and may also not specify a shader ty type. This allows using shaders compiled through a separate build system.

root_path_env: "..."

Instead of searching relative to your Cargo.toml, search relative to some other folder specified by this env variable. The intended use case is using OUT_DIR to be able to load shaders generated by your build script. Defaults to CARGO_MANIFEST_DIR corresponding to the folder of your Cargo.toml.

See cargo-env-vars for a full set of env variables set by cargo. It is also possible to specify env variables from within the build script using the following:

println!("cargo:rustc-env=SHADER_OUT_DIR={shader_out_dir}");

shaders: { first: { src: "...", ty: "..." }, ... }

With these options the user can compile several shaders in a single macro invocation. Each entry key will be the suffix of the generated load function (load_first in this case). However, all other Rust structs translated from the shader source will be shared between shaders. The macro checks that the source structs with the same names between different shaders have the same declaration signature, and throws a compile-time error if they don’t.

Each entry expects a src, path, bytes, and ty pairs same as above.

include: ["...", "...", ...]

Specifies the standard include directories to be searched through when using the #include <...> directive within a shader source. Include directories can be absolute or relative to your Cargo.toml. If path was specified, relative paths can also be used (#include "..."), without the need to specify one or more standard include directories. Relative paths are relative to the directory which contains the source file the #include "..." directive is declared in.

define: [("NAME", "VALUE"), ...]

Adds the given macro definitions to the pre-processor. This is equivalent to passing the -DNAME=VALUE argument on the command line.

vulkan_version: "major.minor" and spirv_version: "major.minor"

Sets the Vulkan and SPIR-V versions to compile into, respectively. These map directly to the set_target_env and set_target_spirv compile options. If neither option is specified, then SPIR-V 1.0 code targeting Vulkan 1.0 will be generated.

The generated code must be supported by the device at runtime. If not, then an error will be returned when calling load.

generate_structs: true

Generate rust structs that represent the structs contained in the shader. They all implement BufferContents, which allows then to be passed to the shader, without having to worry about the layout of the struct manually. However, some use-cases, such as Rust-GPU, may not have any use for such structs, and may choose to disable them.

custom_derives: [Clone, Default, PartialEq, ...]

Extends the list of derive macros that are added to the derive attribute of Rust structs that represent shader structs.

By default, each generated struct derives Clone and Copy. If the struct has unsized members none of the derives are applied on the struct, except BufferContents, which is always derived.

linalg_type: "..."

Specifies the way that linear algebra types should be generated. It can be any of the following:

• std
• cgmath
• nalgebra

The default is std, which uses arrays to represent vectors and matrices. Note that if the chosen crate doesn’t have a type that represents a certain linear algebra type (e.g. mat3, or a rectangular matrix) then the macro will default back to arrays for that type.

If you use linear algebra types from a third-party crate, then you have to have the crate in your dependencies with the appropriate feature enabled that adds bytemuck support.

dump: true

The crate fails to compile but prints the generated Rust code to stdout.

Cargo features

Feature	Description
shaderc-build-from-source	Build the shaderc library from source when compiling.
shaderc-debug	Compile shaders with debug information included.

Macros

shader