Add support for object and mesh shader (#264)

* Add support for object and mesh shader

* Remove unnecessary unsafe block

examples/mesh-shader/main.rs

@@ -0,0 +1,118 @@
+extern crate objc;
+
+use cocoa::{appkit::NSView, base::id as cocoa_id};
+use core_graphics_types::geometry::CGSize;
+
+use metal::*;
+use objc::{rc::autoreleasepool, runtime::YES};
+use std::mem;
+use winit::platform::macos::WindowExtMacOS;
+
+use winit::{
+    event::{Event, WindowEvent},
+    event_loop::ControlFlow,
+};
+
+fn prepare_render_pass_descriptor(descriptor: &RenderPassDescriptorRef, texture: &TextureRef) {
+    let color_attachment = descriptor.color_attachments().object_at(0).unwrap();
+
+    color_attachment.set_texture(Some(texture));
+    color_attachment.set_load_action(MTLLoadAction::Clear);
+    color_attachment.set_clear_color(MTLClearColor::new(0.2, 0.2, 0.25, 1.0));
+    color_attachment.set_store_action(MTLStoreAction::Store);
+}
+
+fn main() {
+    let events_loop = winit::event_loop::EventLoop::new();
+    let size = winit::dpi::LogicalSize::new(800, 600);
+
+    let window = winit::window::WindowBuilder::new()
+        .with_inner_size(size)
+        .with_title("Metal Mesh Shader Example".to_string())
+        .build(&events_loop)
+        .unwrap();
+
+    let device = Device::system_default().expect("no device found");
+
+    let layer = MetalLayer::new();
+    layer.set_device(&device);
+    layer.set_pixel_format(MTLPixelFormat::BGRA8Unorm);
+    layer.set_presents_with_transaction(false);
+
+    unsafe {
+        let view = window.ns_view() as cocoa_id;
+        view.setWantsLayer(YES);
+        view.setLayer(mem::transmute(layer.as_ref()));
+    }
+
+    let draw_size = window.inner_size();
+    layer.set_drawable_size(CGSize::new(draw_size.width as f64, draw_size.height as f64));
+
+    let library_path = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("examples/mesh-shader/shaders.metallib");
+    let library = device.new_library_with_file(library_path).unwrap();
+
+    let mesh = library.get_function("mesh_function", None).unwrap();
+    let frag = library.get_function("fragment_function", None).unwrap();
+
+    let pipeline_state_desc = MeshRenderPipelineDescriptor::new();
+    pipeline_state_desc
+        .color_attachments()
+        .object_at(0)
+        .unwrap()
+        .set_pixel_format(MTLPixelFormat::BGRA8Unorm);
+    pipeline_state_desc.set_mesh_function(Some(&mesh));
+    pipeline_state_desc.set_fragment_function(Some(&frag));
+
+    let pipeline_state = device
+        .new_mesh_render_pipeline_state(&pipeline_state_desc)
+        .unwrap();
+
+    let command_queue = device.new_command_queue();
+
+    events_loop.run(move |event, _, control_flow| {
+        autoreleasepool(|| {
+            *control_flow = ControlFlow::Poll;
+
+            match event {
+                Event::WindowEvent { event, .. } => match event {
+                    WindowEvent::CloseRequested => *control_flow = ControlFlow::Exit,
+                    WindowEvent::Resized(size) => {
+                        layer.set_drawable_size(CGSize::new(size.width as f64, size.height as f64));
+                    }
+                    _ => (),
+                },
+                Event::MainEventsCleared => {
+                    window.request_redraw();
+                }
+                Event::RedrawRequested(_) => {
+                    let drawable = match layer.next_drawable() {
+                        Some(drawable) => drawable,
+                        None => return,
+                    };
+
+                    let render_pass_descriptor = RenderPassDescriptor::new();
+
+                    prepare_render_pass_descriptor(&render_pass_descriptor, drawable.texture());
+
+                    let command_buffer = command_queue.new_command_buffer();
+                    let encoder =
+                        command_buffer.new_render_command_encoder(&render_pass_descriptor);
+
+                    encoder.set_render_pipeline_state(&pipeline_state);
+                    encoder.draw_mesh_threads(
+                        MTLSize::new(1, 1, 1),
+                        MTLSize::new(1, 1, 1),
+                        MTLSize::new(1, 1, 1),
+                    );
+
+                    encoder.end_encoding();
+
+                    command_buffer.present_drawable(&drawable);
+                    command_buffer.commit();
+                }
+                _ => {}
+            }
+        });
+    });
+}

examples/mesh-shader/shaders.metal

@@ -0,0 +1,30 @@
+#include <metal_stdlib>
+
+using namespace metal;
+
+struct VertexOut {
+    float4 position [[position]];
+};
+
+using mesh_t = mesh<VertexOut, void, 3, 1, topology::triangle>;
+
+[[mesh]] void mesh_function(mesh_t m) {
+    VertexOut v;
+    v.position = float4(-1.0, -1.0, 0.0, 1.0);
+
+    m.set_primitive_count(1);
+
+    m.set_vertex(0, v);
+    v.position = float4(0.0, 1.0, 0.0, 1.0);
+    m.set_vertex(1, v);
+    v.position = float4(1.0, -1.0, 0.0, 1.0);
+    m.set_vertex(2, v);
+
+    m.set_index(0, 0);
+    m.set_index(1, 1);
+    m.set_index(2, 2);
+}
+
+fragment half4 fragment_function() {
+    return half4(0.1, 1.0, 0.1, 1.0);
+}

src/device.rs

@@ -1899,6 +1899,45 @@ impl DeviceRef {
         }
     }
 
+    /// Only available on (macos(13.0), ios(16.0))
+    pub fn new_mesh_render_pipeline_state_with_reflection(
+        &self,
+        descriptor: &MeshRenderPipelineDescriptorRef,
+        reflection_options: MTLPipelineOption,
+    ) -> Result<(RenderPipelineState, RenderPipelineReflection), String> {
+        unsafe {
+            let mut reflection: *mut Object = ptr::null_mut();
+            let pipeline_state: *mut MTLRenderPipelineState = try_objc! { err =>
+                msg_send![self, newRenderPipelineStateWithMeshDescriptor:descriptor
+                                                             options:reflection_options
+                                                          reflection:&mut reflection
+                                                               error:&mut err]
+            };
+
+            let state = RenderPipelineState::from_ptr(pipeline_state);
+
+            let () = msg_send![reflection, retain];
+            let reflection = RenderPipelineReflection::from_ptr(reflection as _);
+
+            Ok((state, reflection))
+        }
+    }
+
+    /// Only available on (macos(13.0), ios(16.0))
+    pub fn new_mesh_render_pipeline_state(
+        &self,
+        descriptor: &MeshRenderPipelineDescriptorRef,
+    ) -> Result<RenderPipelineState, String> {
+        unsafe {
+            let pipeline_state: *mut MTLRenderPipelineState = try_objc! { err =>
+                msg_send![self, newRenderPipelineStateWithMeshDescriptor:descriptor
+                                                               error:&mut err]
+            };
+
+            Ok(RenderPipelineState::from_ptr(pipeline_state))
+        }
+    }
+
     pub fn new_compute_pipeline_state_with_function(
         &self,
         function: &FunctionRef,