build: separate out targets

README.md

@@ -66,13 +66,37 @@ Safe and sound Rust bindings to [SPIRV-Cross](https://github.com/KhronosGroup/SP
  }
  ```
 
+## Features
+By default, the `glsl`, `hlsl`, and `msl` features are enabled by default. The `cpp` and `json` targets can be enabled
+in Cargo.toml
+
+```toml
+ [dependencies]
+ spirv-cross2 = { features = ["cpp", "json"] }
+```
+
+SPIRV-Cross will only be built with support for enabled targets. If you want to only perform reflection and shrink the binary size,
+you can disable all but the `None` target.
+
+```toml
+ [dependencies]
+ spirv-cross2 = { default-features = false }
+```
+
+To enable all features, including `f16` and vector constant support, use the `full` feature.
+
+```toml
+ [dependencies]
+ spirv-cross2 = { features = ["full"] }
+```
+
 ### `f16` and vector specialization constants support
 When querying specialization constants, spirv-cross2 includes optional support for `f16` via [half](https://crates.io/crates/half) and `Vec2`, `Vec3`, `Vec4`, and `Mat4` types
-via [gfx-maths](https://crates.io/crates/gfx-maths). This is included by default, but can be disabled by disabling default features.
+via [gfx-maths](https://crates.io/crates/gfx-maths).
 
 ```toml
-[dependencies]
-spirv-cross2 = { default-features = false } 
+ [dependencies]
+ spirv-cross2 = { features = ["f16", "half"] }
 ```
 
 ## License

spirv-cross-sys/Cargo.toml

@@ -17,6 +17,14 @@ bytemuck = "1.17.1"
 num-traits = "0.2"
 num-derive = "0.4.2"
 
+[features]
+glsl = []
+msl = ["glsl"]
+hlsl = ["glsl"]
+json = ["glsl"]
+cpp = ["glsl"]
+
+
 [build-dependencies]
 cc = "1.0"
 glob = "0.3"

spirv-cross-sys/build.rs

@@ -11,11 +11,6 @@ pub fn main() {
         .cpp(true)
         .std("c++14")
         .define("SPIRV_CROSS_CLI", "OFF")
-        .define("SPIRV_CROSS_C_API_GLSL", "1")
-        .define("SPIRV_CROSS_C_API_HLSL", "1")
-        .define("SPIRV_CROSS_C_API_MSL", "1")
-        .define("SPIRV_CROSS_C_API_CPP", "1")
-        .define("SPIRV_CROSS_C_API_REFLECT", "1")
         .includes(&["native/SPIRV-Cross", "native/SPIRV-CROSS/include"])
         .file("native/SPIRV-Cross/spirv_cfg.cpp")
         .file("native/SPIRV-Cross/spirv_cpp.cpp")
@@ -29,6 +24,26 @@ pub fn main() {
         .file("native/SPIRV-Cross/spirv_reflect.cpp")
         .file("native/spirv_cross_c_ext_rs.cpp");
 
+    if cfg!(feature = "glsl") {
+        spvc_build.define("SPIRV_CROSS_C_API_GLSL", "1");
+    }
+
+    if cfg!(feature = "hlsl") {
+        spvc_build.define("SPIRV_CROSS_C_API_HLSL", "1");
+    }
+
+    if cfg!(feature = "msl") {
+        spvc_build.define("SPIRV_CROSS_C_API_MSL", "1");
+    }
+
+    if cfg!(feature = "cpp") {
+        spvc_build.define("SPIRV_CROSS_C_API_CPP", "1");
+    }
+
+    if cfg!(feature = "json") {
+        spvc_build.define("SPIRV_CROSS_C_API_JSON", "1");
+    }
+
     spvc_build.compile("spirv-cross");
     println!("cargo:rustc-link-lib=static=spirv-cross");
 }

spirv-cross2/Cargo.toml

@@ -28,13 +28,21 @@ memchr = "2.7.4"
 spirv = "0.3.0"
 
 [features]
-default = ["gfx-math-types", "f16"]
+default = ["glsl", "hlsl", "msl"]
+full = ["gfx-math-types", "f16", "glsl", "hlsl", "msl", "json", "cpp"]
+
 f16 = ["dep:half"]
 gfx-math-types = ["dep:gfx-maths"]
 
+glsl = ["spirv-cross-sys/glsl"]
+hlsl = ["spirv-cross-sys/hlsl"]
+msl = ["spirv-cross-sys/msl"]
+json = ["spirv-cross-sys/json"]
+cpp = ["spirv-cross-sys/cpp"]
+
 [dev-dependencies]
 glslang = "0.4.0"
 
 [package.metadata.docs.rs]
-features = ["default"]
+features = ["full"]
 rustdoc-args = ["--cfg", "docsrs"]

spirv-cross2/src/compile/mod.rs

@@ -7,12 +7,18 @@ use std::fmt::{Display, Formatter};
 use std::ops::Deref;
 
 /// GLSL compile options.
+#[cfg(feature = "glsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "glsl")))]
 pub mod glsl;
 
 /// HLSL compile options.
+#[cfg(feature = "hlsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "hlsl")))]
 pub mod hlsl;
 
 /// MSL compile options.
+#[cfg(feature = "msl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "msl")))]
 pub mod msl;
 
 impl Sealed for CommonOptions {}

spirv-cross2/src/lib.rs

@@ -61,6 +61,39 @@
 //! Some allocations are made directly in the SPIRV-Cross compiler object. Such allocations
 //! can only live for as long as the borrow to [`Compiler`].
 //!
+//! ## Features
+//! By default, the `glsl`, `hlsl`, and `msl` features are enabled by default. The `cpp` and `json` targets can be enabled
+//! in Cargo.toml
+//!
+//! ```toml
+//! [dependencies]
+//! spirv-cross2 = { features = ["cpp", "json"] }
+//! ```
+//!
+//! SPIRV-Cross will only be built with support for enabled targets. If you want to only perform reflection and shrink the binary size,
+//! you can disable all but the `None` target.
+//!
+//! ```toml
+//! [dependencies]
+//! spirv-cross2 = { default-features = false }
+//! ```
+//!
+//! To enable all features, including `f16` and vector constant support, use the `full` feature.
+//!
+//! ```toml
+//! [dependencies]
+//! spirv-cross2 = { features = ["full"] }
+//! ```
+//!
+//! ### `f16` and vector specialization constants support
+//! When querying specialization constants, spirv-cross2 includes optional support for `f16` via [half](https://crates.io/crates/half) and `Vec2`, `Vec3`, `Vec4`, and `Mat4` types
+//! via [gfx-maths](https://crates.io/crates/gfx-maths).
+//!
+//! ```toml
+//! [dependencies]
+//! spirv-cross2 = { features = ["f16", "half"] }
+//! ```
+//!
 //! ## Usage
 //! Here is an example of using the API to do some reflection and compile to GLSL.
 //!
@@ -106,6 +139,7 @@
 //!     compiler.compile(&options)
 //! }
 //! ```
+//!
 use spirv_cross_sys::{spvc_compiler_s, SpvId};
 
 use crate::cell::{AllocationDropGuard, CrossAllocationCell};

spirv-cross2/src/targets.rs

@@ -6,70 +6,110 @@ use spirv_cross_sys::CompilerBackend;
 /// Reflection only backend, no compilation features
 /// enabled.
 pub struct None;
+
 /// Compile SPIR-V to GLSL.
+#[cfg(feature = "glsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "glsl")))]
 pub struct Glsl;
+
 /// Compile SPIR-V to Metal Shading Language (MSL).
+#[cfg(feature = "msl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "msl")))]
 pub struct Msl;
+
 /// Compile SPIR-V to HLSL.
+#[cfg(feature = "hlsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "hlsl")))]
 pub struct Hlsl;
+
 /// Compile SPIR-V to debuggable C++.
 ///
 /// This backend is deprecated but is included here for completion.
 /// See the [SPIRV-Cross docs](https://github.com/KhronosGroup/SPIRV-Cross?tab=readme-ov-file#using-shaders-generated-from-c-backend)
 /// for how to debug shaders generated from the C++ backend
 #[deprecated = "This backend is deprecated in SPIRV-Cross."]
+#[cfg(feature = "cpp")]
+#[cfg_attr(docsrs, doc(cfg(feature = "cpp")))]
 pub struct Cpp;
+
 /// Compile SPIR-V to a JSON reflection format
+#[cfg(feature = "json")]
+#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
 pub struct Json;
 
 impl Sealed for None {}
 impl Target for None {
     const BACKEND: CompilerBackend = CompilerBackend::None;
 }
 
-impl CompilableTarget for Glsl {
-    type Options = compile::glsl::CompilerOptions;
-}
-impl Sealed for Glsl {}
-impl Target for Glsl {
-    const BACKEND: CompilerBackend = CompilerBackend::Glsl;
+#[cfg(feature = "glsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "glsl")))]
+mod glsl {
+    use super::*;
+    impl CompilableTarget for Glsl {
+        type Options = compile::glsl::CompilerOptions;
+    }
+    impl Sealed for Glsl {}
+    impl Target for Glsl {
+        const BACKEND: CompilerBackend = CompilerBackend::Glsl;
+    }
 }
 
-impl CompilableTarget for Hlsl {
-    type Options = compile::hlsl::CompilerOptions;
-}
-impl Sealed for Hlsl {}
-impl Target for Hlsl {
-    const BACKEND: CompilerBackend = CompilerBackend::Hlsl;
+#[cfg(feature = "hlsl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "hlsl")))]
+mod hlsl {
+    use super::*;
+    impl CompilableTarget for Hlsl {
+        type Options = compile::hlsl::CompilerOptions;
+    }
+    impl Sealed for Hlsl {}
+    impl Target for Hlsl {
+        const BACKEND: CompilerBackend = CompilerBackend::Hlsl;
+    }
 }
 
-impl CompilableTarget for Msl {
-    type Options = compile::msl::CompilerOptions;
-}
-impl Sealed for Msl {}
-impl Target for Msl {
-    const BACKEND: CompilerBackend = CompilerBackend::Msl;
+#[cfg(feature = "msl")]
+#[cfg_attr(docsrs, doc(cfg(feature = "msl")))]
+mod msl {
+    use super::*;
+    impl CompilableTarget for Msl {
+        type Options = compile::msl::CompilerOptions;
+    }
+    impl Sealed for Msl {}
+    impl Target for Msl {
+        const BACKEND: CompilerBackend = CompilerBackend::Msl;
+    }
 }
 
-impl CompilableTarget for Json {
-    type Options = NoOptions;
-}
-impl Sealed for Json {}
-impl Target for Json {
-    const BACKEND: CompilerBackend = CompilerBackend::Json;
+#[cfg(feature = "json")]
+#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
+mod json {
+    use super::*;
+    impl CompilableTarget for Json {
+        type Options = NoOptions;
+    }
+    impl Sealed for Json {}
+    impl Target for Json {
+        const BACKEND: CompilerBackend = CompilerBackend::Json;
+    }
 }
 
-#[allow(deprecated)]
-impl CompilableTarget for Cpp {
-    type Options = NoOptions;
-}
+#[cfg(feature = "cpp")]
+#[cfg_attr(docsrs, doc(cfg(feature = "cpp")))]
+mod cpp {
+    use super::*;
+    #[allow(deprecated)]
+    impl CompilableTarget for Cpp {
+        type Options = NoOptions;
+    }
 
-#[allow(deprecated)]
-impl Sealed for Cpp {}
+    #[allow(deprecated)]
+    impl Sealed for Cpp {}
 
-#[allow(deprecated)]
-impl Target for Cpp {
-    const BACKEND: CompilerBackend = CompilerBackend::Cpp;
+    #[allow(deprecated)]
+    impl Target for Cpp {
+        const BACKEND: CompilerBackend = CompilerBackend::Cpp;
+    }
 }
 
 /// Marker trait for a compiler backend target.