1 files changed, 286 insertions, 0 deletions
diff --git a/third_party/rust/gfx-backend-metal/src/window.rs b/third_party/rust/gfx-backend-metal/src/window.rs
new file mode 100644
index 0000000000..a7040ff8c1
--- /dev/null
+++ b/third_party/rust/gfx-backend-metal/src/window.rs
@@ -0,0 +1,286 @@
+use crate::{
+    device::{Device, PhysicalDevice},
+    internal::Channel,
+    native, Backend, QueueFamily, Shared,
+};
+
+use hal::{format, image, window as w};
+
+use crate::CGRect;
+use metal::{CGFloat, CGSize, CoreAnimationDrawable};
+use objc::rc::autoreleasepool;
+use objc::runtime::Object;
+use parking_lot::Mutex;
+
+use std::borrow::Borrow;
+use std::ptr::NonNull;
+use std::thread;
+
+#[derive(Debug)]
+pub struct Surface {
+    view: Option<NonNull<Object>>,
+    render_layer: Mutex<metal::CoreAnimationLayer>,
+    swapchain_format: metal::MTLPixelFormat,
+    swapchain_format_desc: format::FormatDesc,
+    main_thread_id: thread::ThreadId,
+}
+
+unsafe impl Send for Surface {}
+unsafe impl Sync for Surface {}
+
+impl Surface {
+    pub fn new(view: Option<NonNull<Object>>, layer: metal::CoreAnimationLayer) -> Self {
+        Surface {
+            view,
+            render_layer: Mutex::new(layer),
+            swapchain_format: metal::MTLPixelFormat::Invalid,
+            swapchain_format_desc: format::FormatDesc {
+                bits: 0,
+                dim: (0, 0),
+                packed: false,
+                aspects: format::Aspects::empty(),
+            },
+            main_thread_id: thread::current().id(),
+        }
+    }
+
+    pub(crate) fn dispose(self) {
+        if let Some(view) = self.view {
+            let () = unsafe { msg_send![view.as_ptr(), release] };
+        }
+    }
+
+    fn configure(&self, shared: &Shared, config: &w::SwapchainConfig) -> metal::MTLPixelFormat {
+        info!("build swapchain {:?}", config);
+
+        let caps = &shared.private_caps;
+        let mtl_format = caps
+            .map_format(config.format)
+            .expect("unsupported backbuffer format");
+
+        let render_layer = self.render_layer.lock();
+        let framebuffer_only = config.image_usage == image::Usage::COLOR_ATTACHMENT;
+        let display_sync = config.present_mode != w::PresentMode::IMMEDIATE;
+        let is_mac = caps.os_is_mac;
+        let can_set_next_drawable_timeout = if is_mac {
+            caps.has_version_at_least(10, 13)
+        } else {
+            caps.has_version_at_least(11, 0)
+        };
+        let can_set_display_sync = is_mac && caps.has_version_at_least(10, 13);
+        let drawable_size = CGSize::new(config.extent.width as f64, config.extent.height as f64);
+
+        let device_raw = shared.device.lock();
+        unsafe {
+            // On iOS, unless the user supplies a view with a CAMetalLayer, we
+            // create one as a sublayer. However, when the view changes size,
+            // its sublayers are not automatically resized, and we must resize
+            // it here. The drawable size and the layer size don't correlate
+            #[cfg(target_os = "ios")]
+            {
+                if let Some(view) = self.view {
+                    let main_layer: *mut Object = msg_send![view.as_ptr(), layer];
+                    let bounds: CGRect = msg_send![main_layer, bounds];
+                    let () = msg_send![*render_layer, setFrame: bounds];
+                }
+            }
+            render_layer.set_device(&*device_raw);
+            render_layer.set_pixel_format(mtl_format);
+            render_layer.set_framebuffer_only(framebuffer_only as _);
+
+            // this gets ignored on iOS for certain OS/device combinations (iphone5s iOS 10.3)
+            let () = msg_send![*render_layer, setMaximumDrawableCount: config.image_count as u64];
+
+            render_layer.set_drawable_size(drawable_size);
+            if can_set_next_drawable_timeout {
+                let () = msg_send![*render_layer, setAllowsNextDrawableTimeout:false];
+            }
+            if can_set_display_sync {
+                let () = msg_send![*render_layer, setDisplaySyncEnabled: display_sync];
+            }
+        };
+
+        mtl_format
+    }
+
+    fn dimensions(&self) -> w::Extent2D {
+        let (size, scale): (CGSize, CGFloat) = match self.view {
+            Some(view) if !cfg!(target_os = "macos") => unsafe {
+                let bounds: CGRect = msg_send![view.as_ptr(), bounds];
+                let window: Option<NonNull<Object>> = msg_send![view.as_ptr(), window];
+                let screen = window.and_then(|window| -> Option<NonNull<Object>> {
+                    msg_send![window.as_ptr(), screen]
+                });
+                match screen {
+                    Some(screen) => {
+                        let screen_space: *mut Object = msg_send![screen.as_ptr(), coordinateSpace];
+                        let rect: CGRect = msg_send![view.as_ptr(), convertRect:bounds toCoordinateSpace:screen_space];
+                        let scale_factor: CGFloat = msg_send![screen.as_ptr(), nativeScale];
+                        (rect.size, scale_factor)
+                    }
+                    None => (bounds.size, 1.0),
+                }
+            },
+            _ => unsafe {
+                let render_layer_borrow = self.render_layer.lock();
+                let render_layer = render_layer_borrow.as_ref();
+                let bounds: CGRect = msg_send![render_layer, bounds];
+                let contents_scale: CGFloat = msg_send![render_layer, contentsScale];
+                (bounds.size, contents_scale)
+            },
+        };
+        w::Extent2D {
+            width: (size.width * scale) as u32,
+            height: (size.height * scale) as u32,
+        }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum AcquireMode {
+    Wait,
+    Oldest,
+}
+
+impl Default for AcquireMode {
+    fn default() -> Self {
+        AcquireMode::Oldest
+    }
+}
+
+#[derive(Debug)]
+pub struct SwapchainImage {
+    image: native::Image,
+    view: native::ImageView,
+    drawable: metal::CoreAnimationDrawable,
+}
+
+unsafe impl Send for SwapchainImage {}
+unsafe impl Sync for SwapchainImage {}
+
+impl SwapchainImage {
+    pub(crate) fn into_drawable(self) -> CoreAnimationDrawable {
+        self.drawable
+    }
+}
+
+impl Borrow<native::Image> for SwapchainImage {
+    fn borrow(&self) -> &native::Image {
+        &self.image
+    }
+}
+
+impl Borrow<native::ImageView> for SwapchainImage {
+    fn borrow(&self) -> &native::ImageView {
+        &self.view
+    }
+}
+
+impl w::Surface<Backend> for Surface {
+    fn supports_queue_family(&self, _queue_family: &QueueFamily) -> bool {
+        // we only expose one family atm, so it's compatible
+        true
+    }
+
+    fn capabilities(&self, physical_device: &PhysicalDevice) -> w::SurfaceCapabilities {
+        let current_extent = if self.main_thread_id == thread::current().id() {
+            Some(self.dimensions())
+        } else {
+            warn!("Unable to get the current view dimensions on a non-main thread");
+            None
+        };
+
+        let device_caps = &physical_device.shared.private_caps;
+
+        let can_set_maximum_drawables_count =
+            device_caps.os_is_mac || device_caps.has_version_at_least(11, 2);
+        let can_set_display_sync =
+            device_caps.os_is_mac && device_caps.has_version_at_least(10, 13);
+
+        w::SurfaceCapabilities {
+            present_modes: if can_set_display_sync {
+                w::PresentMode::FIFO | w::PresentMode::IMMEDIATE
+            } else {
+                w::PresentMode::FIFO
+            },
+            composite_alpha_modes: w::CompositeAlphaMode::OPAQUE, //TODO
+            //Note: this is hardcoded in `CAMetalLayer` documentation
+            image_count: if can_set_maximum_drawables_count {
+                2..=3
+            } else {
+                // 3 is the default in `CAMetalLayer` documentation
+                // iOS 10.3 was tested to use 3 on iphone5s
+                3..=3
+            },
+            current_extent,
+            extents: w::Extent2D {
+                width: 4,
+                height: 4,
+            }..=w::Extent2D {
+                width: 4096,
+                height: 4096,
+            },
+            max_image_layers: 1,
+            usage: image::Usage::COLOR_ATTACHMENT
+                | image::Usage::SAMPLED
+                | image::Usage::TRANSFER_SRC
+                | image::Usage::TRANSFER_DST,
+        }
+    }
+
+    fn supported_formats(&self, _physical_device: &PhysicalDevice) -> Option<Vec<format::Format>> {
+        Some(vec![
+            format::Format::Bgra8Unorm,
+            format::Format::Bgra8Srgb,
+            format::Format::Rgba16Sfloat,
+        ])
+    }
+}
+
+impl w::PresentationSurface<Backend> for Surface {
+    type SwapchainImage = SwapchainImage;
+
+    unsafe fn configure_swapchain(
+        &mut self,
+        device: &Device,
+        config: w::SwapchainConfig,
+    ) -> Result<(), w::CreationError> {
+        assert!(image::Usage::COLOR_ATTACHMENT.contains(config.image_usage));
+        self.swapchain_format = self.configure(&device.shared, &config);
+        Ok(())
+    }
+
+    unsafe fn unconfigure_swapchain(&mut self, _device: &Device) {
+        self.swapchain_format = metal::MTLPixelFormat::Invalid;
+    }
+
+    unsafe fn acquire_image(
+        &mut self,
+        _timeout_ns: u64, //TODO: use the timeout
+    ) -> Result<(Self::SwapchainImage, Option<w::Suboptimal>), w::AcquireError> {
+        let render_layer = self.render_layer.lock();
+        let (drawable, texture) = autoreleasepool(|| {
+            let drawable = render_layer.next_drawable().unwrap();
+            (drawable.to_owned(), drawable.texture().to_owned())
+        });
+        let size = render_layer.drawable_size();
+
+        let sc_image = SwapchainImage {
+            image: native::Image {
+                like: native::ImageLike::Texture(texture.clone()),
+                kind: image::Kind::D2(size.width as u32, size.height as u32, 1, 1),
+                mip_levels: 1,
+                format_desc: self.swapchain_format_desc,
+                shader_channel: Channel::Float,
+                mtl_format: self.swapchain_format,
+                mtl_type: metal::MTLTextureType::D2,
+            },
+            view: native::ImageView {
+                texture,
+                mtl_format: self.swapchain_format,
+            },
+            drawable,
+        };
+        Ok((sc_image, None))
+    }
+}