fix: macOS - added portability bit and extension when creating vulkan instance

[schell]

Checklist

• Run cargo clippy.
• Run cargo clippy --target wasm32-unknown-unknown if applicable.
• Add change to CHANGELOG.md. See simple instructions inside file.

Description
wgpu can't select the vulkan backend on macos. This should at least get us a bit further down the path. Here's the relevant discussion on the wgpu users matrix channel

Testing
Run an example (on macos) with RUST_LOG=trace WGPU_BACKEND=vk VK_LOADER_DEBUG=error cargo run --bin skybox --features=vulkan-portability

[schell]

This gets me a little further towards wgpu selecting the vulkan backend, but it still cannot find a suitable GPU adapter. Here's the relevant portions of my log:

[2023-07-21T22:50:40Z INFO  wgpu_example::framework] Initializing the surface...
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] Instance version: 0x4030fa
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] Enabling debug utils
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] Enabling device properties2
[2023-07-21T22:50:40Z INFO  wgpu_core::instance] Adapter Vulkan AdapterInfo { name: "Apple M1", vendor: 4203, device: 218366959, device_type: IntegratedGpu, driver: "MoltenVK", driver_info: "1.2.4", backend: Vulkan }
Using Apple M1 (Vulkan)
[2023-07-21T22:50:40Z DEBUG wgpu_hal::vulkan::adapter] Supported extensions: ["VK_KHR_swapchain", "VK_EXT_image_robustness", "VK_KHR_swapchain_mutable_format", "VK_EXT_robustness2", "VK_KHR_portability_subset"]
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] GENERAL [Loader Message (0x0)]
    	Inserted device layer "VK_LAYER_KHRONOS_validation" (/usr/local/share/vulkan/explicit_layer.d/../../../lib/libVkLayer_khronos_validation.dylib)
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] 	objects: (type: INSTANCE, hndl: 0x157846200, name: ?)
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] GENERAL [Loader Message (0x0)]
    	       Using "Apple M1" with driver: "/usr/local/share/vulkan/icd.d/../../../lib/libMoltenVK.dylib"
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] 	objects: (type: INSTANCE, hndl: 0x157846200, name: ?)
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] GENERAL [ (0x0)]
    	Vulkan semaphores using MTLEvent.
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] 	objects: (type: DEVICE, hndl: 0x1579e3c18, name: ?)
[mvk-error] VK_ERROR_FEATURE_NOT_PRESENT: vkCreateDevice(): Requested physical device feature specified by the 1st flag in VkPhysicalDeviceRobustness2FeaturesEXT is not available on this device.
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] VALIDATION [ (0x0)]
    	VK_ERROR_FEATURE_NOT_PRESENT: vkCreateDevice(): Requested physical device feature specified by the 1st flag in VkPhysicalDeviceRobustness2FeaturesEXT is not available on this device.
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] 	objects: (type: DEVICE, hndl: 0x1579e3c18, name: ?)
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] GENERAL [ (0x0)]
    	Created VkDevice to run on GPU Apple M1 with the following 5 Vulkan extensions enabled:
    		VK_KHR_portability_subset v1
    		VK_KHR_swapchain v70
    		VK_KHR_swapchain_mutable_format v1
    		VK_EXT_image_robustness v1
    		VK_EXT_robustness2 v1
[2023-07-21T22:50:40Z INFO  wgpu_hal::vulkan::instance] 	objects: (type: DEVICE, hndl: 0x1579e3c18, name: ?)
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] GENERAL [Loader Message (0x0)]
    	terminator_CreateDevice: Failed in ICD /usr/local/share/vulkan/icd.d/../../../lib/libMoltenVK.dylib vkCreateDevice call
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] 	objects: (type: INSTANCE, hndl: 0x157846200, name: ?)
ERROR:            terminator_CreateDevice: Failed in ICD /usr/local/share/vulkan/icd.d/../../../lib/libMoltenVK.dylib vkCreateDevice call
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] GENERAL [Loader Message (0x0)]
    	vkCreateDevice:  Failed to create device chain.
[2023-07-21T22:50:40Z ERROR wgpu_hal::vulkan::instance] 	objects: (type: INSTANCE, hndl: 0x157846200, name: ?)
ERROR:            vkCreateDevice:  Failed to create device chain.
[2023-07-21T22:50:40Z WARN  wgpu_hal::vulkan] Unrecognized device error ERROR_FEATURE_NOT_PRESENT
[2023-07-21T22:50:40Z ERROR wgpu::backend::direct] Error in Adapter::request_device: Connection to device was lost during initialization
thread 'main' panicked at 'Unable to find a suitable GPU adapter!: RequestDeviceError', /Users/schell/code/wgpu/examples/common/src/framework.rs:231:10

[eddyb]

Looks like the remaining error is from wgpu-hal making some of its own fields ambiguous:

wgpu/wgpu-hal/src/vulkan/adapter.rs

Lines 1059 to 1065 in ac9ac8b

	robust_buffer_access: phd_features.core.robust_buffer_access != 0,
	robust_image_access: match phd_features.robustness2 {
	Some(ref f) => f.robust_image_access2 != 0,
	None => phd_features
	.image_robustness
	.map_or(false, |ext| ext.robust_image_access != 0),
	},

wgpu/wgpu-hal/src/vulkan/adapter.rs

Lines 234 to 246 in ac9ac8b

	robustness2: if enabled_extensions.contains(&vk::ExtRobustness2Fn::name()) {
	// Note: enabling `robust_buffer_access2` isn't requires, strictly speaking
	// since we can enable `robust_buffer_access` all the time. But it improves
	// program portability, so we opt into it anyway.
	Some(
	vk::PhysicalDeviceRobustness2FeaturesEXT::builder()
	.robust_buffer_access2(private_caps.robust_buffer_access)
	.robust_image_access2(private_caps.robust_image_access)
	.build(),
	)
	} else {
	None
	},

That is, private_caps.robust_buffer_access and private_caps.robust_image_access may come from phd_features.robustness2, but they may just as well not.

I suspect what you want to do is duplicate those two fields of PrivateCapabilities to have versions prefixed with robustness2_ and make sure that the robustness2 bits are only requested if the driver reported them as supported.

[Wumpf]

great first step. confirmed getting the same on my m1 as well :)
Let's continue as @eddyb suggests