Make Vulkan optional on Apple

.travis.yml

@@ -59,6 +59,7 @@ script:
   - cargo test
   # TODO: enable GL backend
   #- (cd wgpu-native && cargo check --features local,glutin)
+  - if [[ $TRAVIS_OS_NAME == "osx" ]]; then (cd wgpu-native && cargo check --features gfx-backend-vulkan); fi
   - if [[ $TRAVIS_OS_NAME == "linux" ]]; then cargo check --release; fi
   - if [[ $TRAVIS_RUST_VERSION == "nightly" ]]; then cargo +nightly install cbindgen; fi
   - if [[ $TRAVIS_RUST_VERSION == "nightly" ]] && [[ $TRAVIS_OS_NAME == "windows" ]]; then

wgpu-native/Cargo.toml

@@ -30,7 +30,6 @@ lazy_static = "1.1.0"
 log = "0.4"
 hal = { package = "gfx-hal", git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }
 gfx-backend-empty = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }
-gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019", features = ["x11"] }
 parking_lot = "0.9"
 raw-window-handle = "0.1"
 rendy-memory = { git = "https://github.com/amethyst/rendy", rev = "a8ac0de977a28d09592d615f8857461622833443" }
@@ -40,7 +39,12 @@ vec_map = "0.8"
 
 [target.'cfg(any(target_os = "ios", target_os = "macos"))'.dependencies]
 gfx-backend-metal = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019", optional = true }
+
+[target.'cfg(all(unix, not(target_os = "ios"), not(target_os = "macos")))'.dependencies]
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019", features = ["x11"] }
 
 [target.'cfg(windows)'.dependencies]
 gfx-backend-dx12 = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }
 gfx-backend-dx11 = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "a084a1f2fec6c9ed928c53e2dc8c1761782b9019" }

wgpu-native/src/hub.rs

@@ -378,6 +378,7 @@ impl<B: GfxBackend> Default for Hub<B> {
 
 #[derive(Debug, Default)]
 pub struct Hubs {
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     vulkan: Hub<backend::Vulkan>,
     #[cfg(any(target_os = "ios", target_os = "macos"))]
     metal: Hub<backend::Metal>,
@@ -408,6 +409,7 @@ pub trait GfxBackend: hal::Backend {
     fn get_surface_mut(surface: &mut Surface) -> &mut Self::Surface;
 }
 
+#[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
 impl GfxBackend for backend::Vulkan {
     const VARIANT: Backend = Backend::Vulkan;
     fn hub() -> &'static Hub<Self> {

wgpu-native/src/instance.rs

@@ -32,6 +32,7 @@ use std::marker::PhantomData;
 
 #[derive(Debug)]
 pub struct Instance {
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     vulkan: Option<gfx_backend_vulkan::Instance>,
     #[cfg(any(target_os = "ios", target_os = "macos"))]
     metal: gfx_backend_metal::Instance,
@@ -44,7 +45,7 @@ pub struct Instance {
 impl Instance {
     pub(crate) fn new(name: &str, version: u32) -> Self {
         Instance {
-            //TODO: reconsider once `create` returns a `Result`
+            #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
             vulkan: gfx_backend_vulkan::Instance::create(name, version).ok(),
             #[cfg(any(target_os = "ios", target_os = "macos"))]
             metal: gfx_backend_metal::Instance::create(name, version).unwrap(),
@@ -62,6 +63,7 @@ type GfxSurface<B> = <B as hal::Backend>::Surface;
 pub struct Surface {
     pub(crate) swap_chain: Option<SwapChainId>,
     pub(crate) ref_count: RefCount,
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     pub(crate) vulkan: Option<GfxSurface<backend::Vulkan>>,
     #[cfg(any(target_os = "ios", target_os = "macos"))]
     pub(crate) metal: GfxSurface<backend::Metal>,
@@ -167,6 +169,7 @@ pub fn wgpu_create_surface(raw_handle: raw_window_handle::RawWindowHandle) -> Su
         Rwh::IOS(h) => Surface {
             swap_chain: None,
             ref_count,
+            #[cfg(feature = "gfx-backend-vulkan")]
             vulkan: None,
             metal: instance
                 .metal
@@ -176,6 +179,7 @@ pub fn wgpu_create_surface(raw_handle: raw_window_handle::RawWindowHandle) -> Su
         Rwh::MacOS(h) => Surface {
             swap_chain: None,
             ref_count,
+            #[cfg(feature = "gfx-backend-vulkan")]
             vulkan: instance
                 .vulkan
                 .as_ref()
@@ -245,6 +249,7 @@ pub extern "C" fn wgpu_create_surface_from_metal_layer(layer: *mut std::ffi::c_v
     let surface = Surface {
         swap_chain: None,
         ref_count: LifeGuard::new().ref_count,
+        #[cfg(feature = "gfx-backend-vulkan")]
         vulkan: None, //TODO: currently requires `NSView`
         metal: GLOBAL
             .instance
@@ -296,6 +301,7 @@ pub fn request_adapter(
     let id_dx12 = find_input(Backend::Dx12);
     let id_dx11 = find_input(Backend::Dx11);
 
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     let mut adapters_vk = match instance.vulkan {
         Some(ref inst) if id_vulkan.is_some() => {
             let adapters = inst.enumerate_adapters();
@@ -361,6 +367,7 @@ pub fn request_adapter(
     let mut token = Token::root();
 
     let mut selected = preferred_gpu.unwrap_or(0);
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     {
         if selected < adapters_vk.len() {
             let adapter = Adapter {
@@ -421,7 +428,7 @@ pub fn request_adapter(
         }
         selected -= adapters_dx11.len();
     }
-    let _ = (selected, id_metal, id_dx12, id_dx11);
+    let _ = (selected, id_vulkan, id_metal, id_dx12, id_dx11);
     None
 }
 

wgpu-native/src/lib.rs

@@ -6,6 +6,7 @@ pub mod backend {
     pub use gfx_backend_empty::Backend as Empty;
     #[cfg(any(target_os = "ios", target_os = "macos"))]
     pub use gfx_backend_metal::Backend as Metal;
+    #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
     pub use gfx_backend_vulkan::Backend as Vulkan;
 }
 
@@ -202,6 +203,7 @@ pub enum InputState {}
 macro_rules! gfx_select {
     ($id:expr => $function:ident( $($param:expr),+ )) => {
         match $id.backend() {
+            #[cfg(any(not(any(target_os = "ios", target_os = "macos")), feature = "gfx-backend-vulkan"))]
             $crate::Backend::Vulkan => $function::<$crate::backend::Vulkan>( $($param),+ ),
             #[cfg(any(target_os = "ios", target_os = "macos"))]
             $crate::Backend::Metal => $function::<$crate::backend::Metal>( $($param),+ ),