Support the VK_KHR_maintenance2 extension.

We don't really restrict which usages you can request on an image, so
the `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT` doesn't really apply to us.
Since we don't yet support tessellation, we don't support
`VkPipelineTessellationDomainOriginStateCreateInfo`, either. Finally,
as near as I can tell, we don't really do anything with input
attachments, so any `VkRenderPassInputAttachmentAspectCreateInfo` will
be ignored.

I'm not sure if creating image views of compressed images using an
uncompressed format will work. Metal's docs say texture views between
any two color formats of the same size will work, but they also
specifically call out converting between sRGB and non-sRGB compressed
formats, which implies that, say, creating an `RG32Uint` view on a
`BC1_RGBA` texture may not work. Thus, I've logged any uses of the
`VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT`.

MoltenVK/MoltenVK/GPUObjects/MVKDevice.h

@@ -86,7 +86,7 @@ public:
 	void getProperties(VkPhysicalDeviceProperties* properties);
 
 	/** Populates the specified structure with the properties of this device. */
-	void getProperties(VkPhysicalDeviceProperties2KHR* properties);
+	void getProperties(VkPhysicalDeviceProperties2* properties);
 
 	/** Returns whether the specified format is supported on this device. */
 	bool getFormatIsSupported(VkFormat format);

MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm

@@ -73,9 +73,9 @@ void MVKPhysicalDevice::getProperties(VkPhysicalDeviceProperties* properties) {
     if (properties) { *properties = _properties; }
 }
 
-void MVKPhysicalDevice::getProperties(VkPhysicalDeviceProperties2KHR* properties) {
+void MVKPhysicalDevice::getProperties(VkPhysicalDeviceProperties2* properties) {
     if (properties) {
-        properties->sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2_KHR;
+        properties->sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2;
         properties->properties = _properties;
         auto* next = (VkStructureType*)properties->pNext;
         while (next) {
@@ -86,8 +86,14 @@ void MVKPhysicalDevice::getProperties(VkPhysicalDeviceProperties2KHR* properties
                 next = (VkStructureType*)pushDescProps->pNext;
                 break;
             }
+            case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES: {
+                auto* pointClipProps = (VkPhysicalDevicePointClippingProperties*)next;
+                pointClipProps->pointClippingBehavior = VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES;
+                next = (VkStructureType*)pointClipProps->pNext;
+                break;
+            }
             default:
-                next = (VkStructureType*)((VkPhysicalDeviceProperties2KHR*)next)->pNext;
+                next = (VkStructureType*)((VkPhysicalDeviceProperties2*)next)->pNext;
                 break;
             }
         }

MoltenVK/MoltenVK/GPUObjects/MVKImage.h

@@ -291,6 +291,7 @@ protected:
 
     MVKImage* _image;
     VkImageSubresourceRange _subresourceRange;
+    VkImageUsageFlags _usage;
 	id<MTLTexture> _mtlTexture;
 	std::mutex _lock;
 	MTLPixelFormat _mtlPixelFormat;

MoltenVK/MoltenVK/GPUObjects/MVKImage.mm

@@ -471,6 +471,10 @@ MVKImage::MVKImage(MVKDevice* device, const VkImageCreateInfo* pCreateInfo) : MV
 
     _byteAlignment = _device->_pProperties->limits.minTexelBufferOffsetAlignment;
 
+    if (pCreateInfo->flags & VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT) {
+        mvkNotifyErrorWithText(VK_ERROR_FEATURE_NOT_PRESENT, "vkCreateImage() : Metal may not allow uncompressed views of compressed images.");
+    }
+
     // Adjust the info components to be compatible with Metal, then use the modified versions
     // to set other config info. Vulkan allows unused extent dimensions to be zero, but Metal
     // requires minimum of one. Adjust samples and miplevels for the right texture type.
@@ -659,6 +663,23 @@ MVKImageView::MVKImageView(MVKDevice* device, const VkImageViewCreateInfo* pCrea
 	validateImageViewConfig(pCreateInfo);
 
 	_image = (MVKImage*)pCreateInfo->image;
+	_usage = _image->_usage;
+
+	auto* next = (VkStructureType*)pCreateInfo->pNext;
+	while (next) {
+		switch (*next) {
+		case VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO: {
+			auto* pViewUsageInfo = (VkImageViewUsageCreateInfo*)next;
+			if (!(pViewUsageInfo->usage & ~_usage))
+				_usage = pViewUsageInfo->usage;
+			next = (VkStructureType*)pViewUsageInfo->pNext;
+			break;
+		}
+		default:
+			next = (VkStructureType*)((VkImageViewCreateInfo*)next)->pNext;
+			break;
+		}
+	}
 
 	// Remember the subresource range, and determine the actual number of mip levels and texture slices
     _subresourceRange = pCreateInfo->subresourceRange;
@@ -685,9 +706,9 @@ void MVKImageView::validateImageViewConfig(const VkImageViewCreateInfo* pCreateI
 	if ((viewType == VK_IMAGE_VIEW_TYPE_2D || viewType == VK_IMAGE_VIEW_TYPE_2D_ARRAY) && (imgType == VK_IMAGE_TYPE_3D)) {
 		if (pCreateInfo->subresourceRange.layerCount != image->_extent.depth) {
 			setConfigurationResult(mvkNotifyErrorWithText(VK_ERROR_FEATURE_NOT_PRESENT, "vkCreateImageView(): Metal does not support views on a subset of a 3D texture."));
-		} else if (!(image->_usage & VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT)) {
+		} else if (!(_usage & VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT)) {
 			setConfigurationResult(mvkNotifyErrorWithText(VK_ERROR_FEATURE_NOT_PRESENT, "vkCreateImageView(): 2D views on 3D images are only supported for color attachments."));
-		} else if (image->_usage & ~VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT) {
+		} else if (_usage & ~VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT) {
 			mvkNotifyErrorWithText(VK_ERROR_FEATURE_NOT_PRESENT, "vkCreateImageView(): 2D views on 3D images are only supported for color attachments.");
 		}
 	}

MoltenVK/MoltenVK/Layers/MVKExtensions.def

@@ -36,6 +36,7 @@ MVK_EXTENSION(KHR_get_memory_requirements2, KHR_GET_MEMORY_REQUIREMENTS_2)
 MVK_EXTENSION(KHR_get_physical_device_properties2, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2)
 MVK_EXTENSION(KHR_image_format_list, KHR_IMAGE_FORMAT_LIST)
 MVK_EXTENSION(KHR_maintenance1, KHR_MAINTENANCE1)
+MVK_EXTENSION(KHR_maintenance2, KHR_MAINTENANCE2)
 MVK_EXTENSION(KHR_push_descriptor, KHR_PUSH_DESCRIPTOR)
 MVK_EXTENSION(KHR_shader_draw_parameters, KHR_SHADER_DRAW_PARAMETERS)
 MVK_EXTENSION(KHR_surface, KHR_SURFACE)