Add optional support for VkPhysicalDeviceFeatures::wideLines.

- Add MVK_USE_METAL_PRIVATE_API build setting to allow MoltenVK
  to be built with access to Metal private API calls.
- Add support for VkPhysicalDeviceFeatures::wideLines feature
  when MVK_USE_METAL_PRIVATE_API is enabled in a MoltenVK build.
- Set lineWidthRange and lineWidthGranularity to reasonable arbitrary values.

Docs/Whats_New.md

@@ -18,6 +18,8 @@ MoltenVK 1.2.8
 
 Released TBD
 
+- Add `MVK_USE_METAL_PRIVATE_API` build setting to allow **MoltenVK** to be built with access to _Metal_ private API calls.
+- Add support for `VkPhysicalDeviceFeatures::wideLines` feature when `MVK_USE_METAL_PRIVATE_API` is enabled in a **MoltenVK** build.
 - Fix potential crash when using multi-planar images.
 - Ensure buffers available for buffer addresses in push constants.
 - Support `libMoltenVK.dylib` for _iOS Simulator_ architecture.

MoltenVK/MoltenVK/Commands/MVKCmdRendering.h

@@ -607,6 +607,25 @@ protected:
 };
 
 
+#pragma mark -
+#pragma mark MVKCmdSetLineWidth
+
+/** Vulkan command to dynamically set the line width. */
+class MVKCmdSetLineWidth : public MVKCommand {
+
+public:
+	VkResult setContent(MVKCommandBuffer* cmdBuff,
+						float lineWidth);
+
+	void encode(MVKCommandEncoder* cmdEncoder) override;
+
+protected:
+	MVKCommandTypePool<MVKCommand>* getTypePool(MVKCommandPool* cmdPool) override;
+
+	float _lineWidth;
+};
+
+
 #pragma mark -
 #pragma mark MVKCmdSetPrimitiveTopology
 

MoltenVK/MoltenVK/Commands/MVKCmdRendering.mm

@@ -512,6 +512,20 @@ void MVKCmdSetPolygonMode::encode(MVKCommandEncoder* cmdEncoder) {
 }
 
 
+#pragma mark -
+#pragma mark MVKCmdSetLineWidth
+
+VkResult MVKCmdSetLineWidth::setContent(MVKCommandBuffer* cmdBuff,
+										float lineWidth) {
+	_lineWidth = lineWidth;
+	return VK_SUCCESS;
+}
+
+void MVKCmdSetLineWidth::encode(MVKCommandEncoder* cmdEncoder) {
+	cmdEncoder->_renderingState.setLineWidth(_lineWidth, true);
+}
+
+
 #pragma mark -
 #pragma mark MVKCmdSetPrimitiveTopology
 

MoltenVK/MoltenVK/Commands/MVKCommandEncoderState.h

@@ -263,6 +263,8 @@ public:
 
 	void setPolygonMode(VkPolygonMode polygonMode, bool isDynamic);
 
+	void setLineWidth(float lineWidth, bool isDynamic);
+
 	void setBlendConstants(float blendConstants[4], bool isDynamic);
 
 	void setDepthBias(const VkPipelineRasterizationStateCreateInfo& vkRasterInfo);
@@ -322,7 +324,8 @@ protected:
 	MTLPrimitiveType _mtlPrimitiveTopology[StateScope::Count] = { MTLPrimitiveTypePoint, MTLPrimitiveTypePoint };
 	MTLDepthClipMode _mtlDepthClipEnable[StateScope::Count] = { MTLDepthClipModeClip, MTLDepthClipModeClip };
 	MTLTriangleFillMode _mtlPolygonMode[StateScope::Count] = { MTLTriangleFillModeFill, MTLTriangleFillModeFill };
-	uint32_t _mtlPatchControlPoints[StateScope::Count] = {};
+	float _mtlLineWidth[StateScope::Count] = { 1, 1 };
+	uint32_t _mtlPatchControlPoints[StateScope::Count] = { 0, 0 };
 	MVKRenderStateFlags _dirtyStates;
 	MVKRenderStateFlags _modifiedStates;
 	bool _mtlSampleLocationsEnable[StateScope::Count] = {};

MoltenVK/MoltenVK/Commands/MVKCommandEncoderState.mm

@@ -322,6 +322,11 @@ void MVKRenderingCommandEncoderState::setPolygonMode(VkPolygonMode polygonMode,
 	getContent(_isPolygonModePoint, isDynamic) = (polygonMode == VK_POLYGON_MODE_POINT);
 }
 
+void MVKRenderingCommandEncoderState::setLineWidth(float lineWidth, bool isDynamic) {
+	auto mtlLineWidth = lineWidth;
+	setMTLContent(LineWidth);
+}
+
 void MVKRenderingCommandEncoderState::setBlendConstants(float blendConstants[4], bool isDynamic) {
 	MVKColor32 mtlBlendConstants;
 	mvkCopy(mtlBlendConstants.float32, blendConstants, 4);
@@ -537,6 +542,13 @@ bool MVKRenderingCommandEncoderState::needsMetalRenderPassRestart() {
 
 #pragma mark Encoding
 
+#if MVK_USE_METAL_PRIVATE_API
+// An extension of the MTLRenderCommandEncoder protocol to declare the setLineWidth: method.
+@protocol MVKMTLRenderCommandEncoderLineWidth <MTLRenderCommandEncoder>
+-(void) setLineWidth: (float) width;
+@end
+#endif
+
 void MVKRenderingCommandEncoderState::encodeImpl(uint32_t stage) {
 	if (stage != kMVKGraphicsStageRasterization) { return; }
 
@@ -549,6 +561,16 @@ void MVKRenderingCommandEncoderState::encodeImpl(uint32_t stage) {
 		auto& bcFlt = getMTLContent(BlendConstants).float32;
 		[rendEnc setBlendColorRed: bcFlt[0] green: bcFlt[1] blue: bcFlt[2] alpha: bcFlt[3]];
 	}
+
+#if MVK_USE_METAL_PRIVATE_API
+	if (isDirty(LineWidth)) {
+		auto lineWidthRendEnc = (id<MVKMTLRenderCommandEncoderLineWidth>)rendEnc;
+		if ([lineWidthRendEnc respondsToSelector: @selector(setLineWidth:)]) {
+			[lineWidthRendEnc setLineWidth: getMTLContent(LineWidth)];
+		}
+	}
+#endif
+
 	if (isDirty(DepthBiasEnable) || isDirty(DepthBias)) {
 		if (getMTLContent(DepthBiasEnable)) {
 			auto& db = getMTLContent(DepthBias);

MoltenVK/MoltenVK/Commands/MVKCommandTypePools.def

@@ -104,6 +104,7 @@ MVK_CMD_TYPE_POOL(SetFrontFace)
 MVK_CMD_TYPE_POOL(SetPrimitiveTopology)
 MVK_CMD_TYPE_POOL(SetPrimitiveRestartEnable)
 MVK_CMD_TYPE_POOL(SetPolygonMode)
+MVK_CMD_TYPE_POOL(SetLineWidth)
 MVK_CMD_TYPE_POOL(SetPatchControlPoints)
 MVK_CMD_TYPE_POOL(SetRasterizerDiscardEnable)
 MVK_CMD_TYPE_POOLS_FROM_2_THRESHOLDS(BindVertexBuffers, 1, 2)

MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm

@@ -2341,6 +2341,7 @@ void MVKPhysicalDevice::initFeatures() {
     _features.depthBiasClamp = true;
     _features.fillModeNonSolid = true;
     _features.largePoints = true;
+	_features.wideLines = bool(MVK_USE_METAL_PRIVATE_API);
     _features.alphaToOne = true;
     _features.samplerAnisotropy = true;
     _features.shaderImageGatherExtended = true;
@@ -2761,8 +2762,8 @@ void MVKPhysicalDevice::initLimits() {
 
     _properties.limits.pointSizeGranularity = 1;
     _properties.limits.lineWidthRange[0] = 1;
-    _properties.limits.lineWidthRange[1] = 1;
-    _properties.limits.lineWidthGranularity = 0;
+    _properties.limits.lineWidthRange[1] = _features.wideLines ? 8 : 1;
+    _properties.limits.lineWidthGranularity = _features.wideLines ? 0.125f : 0;
 
     _properties.limits.standardSampleLocations = VK_TRUE;
     _properties.limits.strictLines = _properties.vendorID == kIntelVendorId || _properties.vendorID == kNVVendorId;

MoltenVK/MoltenVK/GPUObjects/MVKPipeline.mm

@@ -311,6 +311,7 @@ void MVKGraphicsPipeline::encode(MVKCommandEncoder* cmdEncoder, uint32_t stage)
 				cmdEncoder->_renderingState.setCullMode(_rasterInfo.cullMode, false);
 				cmdEncoder->_renderingState.setFrontFace(_rasterInfo.frontFace, false);
 				cmdEncoder->_renderingState.setPolygonMode(_rasterInfo.polygonMode, false);
+				cmdEncoder->_renderingState.setLineWidth(_rasterInfo.lineWidth, false);
 				cmdEncoder->_renderingState.setDepthBias(_rasterInfo);
 				cmdEncoder->_renderingState.setDepthClipEnable( !_rasterInfo.depthClampEnable, false );
 			}

MoltenVK/MoltenVK/Utility/MVKEnvironment.h

@@ -73,6 +73,19 @@
 #	define MVK_SUPPORT_IOSURFACE_BOOL (__TV_OS_VERSION_MIN_REQUIRED >= __TVOS_11_0)
 #endif
 
+/**
+ * Enable use of private Metal APIs.
+ *
+ * Enabling this build setting during a MoltenVK build will allow MoltenVK to
+ * extend its functionality by using certain private Metal API calls, but it 
+ * will also disqualify the app from being distributed via Apple App Stores.
+ *
+ * Disabled by default.
+ */
+#ifndef MVK_USE_METAL_PRIVATE_API
+#	define MVK_USE_METAL_PRIVATE_API		0
+#endif
+
 
 #pragma mark -
 #pragma mark MoltenVK Configuration

MoltenVK/MoltenVK/Vulkan/vulkan.mm

@@ -1466,6 +1466,7 @@ MVK_PUBLIC_VULKAN_SYMBOL void vkCmdSetLineWidth(
 	float                                       lineWidth) {
 
 	MVKTraceVulkanCallStart();
+	MVKAddCmd(SetLineWidth, commandBuffer, lineWidth);
 	MVKTraceVulkanCallEnd();
 }
 

README.md

@@ -24,6 +24,9 @@ Table of Contents
 	- [Using MoltenVK Directly](#download)
 - [Fetching **MoltenVK** Source Code](#install)
 - [Building **MoltenVK**](#building)
+	- [Building from the Command Line](#command_line_build)
+	- [Hiding _Vulkan_ API Symbols](#hiding_vulkan_symbols)
+	- [Accessing _Metal_ Private API calls](#metal_private_api)
 - [Running **MoltenVK** Demo Applications](#demos)
 - [Using **MoltenVK** in Your Application](#using)
 - [**MoltenVK** and *Vulkan* Compliance](#compliance)
@@ -236,6 +239,7 @@ to the **MoltenVK** libraries and frameworks in the `Package/Latest` directory,
 to test your app with either a **_Debug_** build, or a higher-performance **_Release_** build.
 
 
+<a name="command_line_build"></a>
 ### Building from the Command Line
 
 If you prefer to build **MoltenVK** from the command line, or to include the activity in a larger build script,
@@ -294,27 +298,37 @@ or
 
 ...etc.
 
-### Hiding Vulkan API Symbols
 
-You can optionally build **MoltenVK** with the Vulkan API static call symbols (`vk*`) hidden, to avoid 
+<a name="hiding_vulkan_symbols"></a>
+### Hiding _Vulkan_ API Symbols
+
+You can optionally build **MoltenVK** with the _Vulkan_ API static call symbols (`vk*`) hidden, to avoid 
 library linking conflicts when statically bound to a _Vulkan_ loader that also exports identical symbols.
 
 To do so, when building **MoltenVK**, set the build setting `MVK_HIDE_VULKAN_SYMBOLS=1`.
-This build setting can be set in the `MoltenVK.xcodeproj` *Xcode* project,
-or it can be included in any of the `make` build commands. For example:
-
-	make MVK_HIDE_VULKAN_SYMBOLS=1
-or
-
-	make macos MVK_HIDE_VULKAN_SYMBOLS=1
-
-...etc.
+This build setting can be set in the `MoltenVK.xcodeproj` *Xcode* project, or it can be 
+included in any of the `make` command-line build commands [mentioned above](#command_line_build).
 
 With `MVK_HIDE_VULKAN_SYMBOLS=1`, the _Vulkan_ `vkGetInstanceProcAddr()` call remains
 statically bound, to provide the application with the ability to retrieve the remaining
 _Vulkan_ API calls as function pointers.
 
 
+<a name="metal_private_api"></a>
+### Accessing _Metal_ Private API calls
+
+You can optionally build **MoltenVK** with access to private _Metal_ API calls.
+Doing so will allow **MoltenVK** to extend its functionality by using certain private _Metal_ 
+API calls, but it will also disqualify the app from being distributed via _Apple_ App Stores.
+
+To do so, when building **MoltenVK**, set the build setting `MVK_USE_METAL_PRIVATE_API=1`.
+This build setting can be set in the `MoltenVK.xcodeproj` *Xcode* project, or it can be 
+included in any of the `make` command-line build commands [mentioned above](#command_line_build).
+
+Functionality added with `MVK_USE_METAL_PRIVATE_API` enabled includes:
+- `VkPhysicalDeviceFeatures::wideLines`
+
+
 <a name="demos"></a>
 Running **MoltenVK** Demo Applications
 --------------------------------------