Add configuration variable for VK_EXT_image_2d_view_of_3d

Since the implementation makes some assumptions as to how 3D texture memory is laid out by the metal driver, only advertise VK_EXT_image_2d_view_of_3d if MVK_CONFIG_ENABLE_2DVIEWOF3D is enabled. MVK_CONFIG_ENABLE_2DVIEWOF3D is off by default.
KhronosGroup · Oct 31, 2024 · c305941 · c305941
1 parent 57d6688
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Showing 6 changed files with 26 additions and 7 deletions.
diff --git a/Docs/MoltenVK_Configuration_Parameters.md b/Docs/MoltenVK_Configuration_Parameters.md
@@ -684,3 +684,15 @@ Determines the style used to implement _Vulkan_ semaphore (`VkSemaphore`) functi
 
 In the special case of `VK_SEMAPHORE_TYPE_TIMELINE` semaphores, **MoltenVK** will always use
 `MTLSharedEvent` if it is available on the platform, regardless of the value of this parameter.
+
+---------------------------------------
+#### MVK_CONFIG_VK_ENABLE_2DVIEWOF3D
+
+##### Type: Boolean
+##### Default: `0`
+
+If enabled, **MoltenVK** will advertise the `VK_EXT_image_2d_view_of_3d` extension. The **MoltenVK** implementation of this extension uses
+`MTLHeap`s to create 2D textures from memory allocated for 3D textures, which makes some assumptions about how a 3D texture's memory is laid
+out by the metal driver.
+
+Note that the use of this feature depends on `MVK_CONFIG_USE_MTLHEAP`.
diff --git a/MoltenVK/MoltenVK/API/mvk_private_api.h b/MoltenVK/MoltenVK/API/mvk_private_api.h
@@ -239,6 +239,7 @@ typedef struct {
 	VkBool32 useMetalPrivateAPI;                                               /**< MVK_CONFIG_USE_METAL_PRIVATE_API */
 	const char* shaderDumpDir;                                                 /**< MVK_CONFIG_SHADER_DUMP_DIR */
 	VkBool32 shaderLogEstimatedGLSL;                                           /**< MVK_CONFIG_SHADER_LOG_ESTIMATED_GLSL */
+	VkBool32 enable2DViewOf3D;                                                 /**< MVK_CONFIG_VK_ENABLE_2DVIEWOF3D */
 } MVKConfiguration;
 
 // Legacy support for renamed struct elements.

diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
@@ -441,7 +441,7 @@
 				portabilityFeatures->imageViewFormatReinterpretation = true;
 				portabilityFeatures->imageViewFormatSwizzle = (_metalFeatures.nativeTextureSwizzle ||
 															   getMVKConfig().fullImageViewSwizzle);
-				portabilityFeatures->imageView2DOn3DImage = true;
+				portabilityFeatures->imageView2DOn3DImage = getMVKConfig().enable2DViewOf3D;
 				portabilityFeatures->multisampleArrayImage = _metalFeatures.multisampleArrayTextures;
 				portabilityFeatures->mutableComparisonSamplers = _metalFeatures.depthSampleCompare;
 				portabilityFeatures->pointPolygons = false;
@@ -583,9 +583,11 @@
 				break;
             }
 			case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_2D_VIEW_OF_3D_FEATURES_EXT: {
-				auto* extFeatures = (VkPhysicalDeviceImage2DViewOf3DFeaturesEXT*)next;
-                extFeatures->image2DViewOf3D = true;
-                extFeatures->sampler2DViewOf3D = true;
+                if (getMVKConfig().enable2DViewOf3D) {
+                    auto* extFeatures = (VkPhysicalDeviceImage2DViewOf3DFeaturesEXT*)next;
+                    extFeatures->image2DViewOf3D = true;
+                    extFeatures->sampler2DViewOf3D = true;
+                }
 				break;
 			}
 			default:

diff --git a/MoltenVK/MoltenVK/Utility/MVKConfigMembers.def b/MoltenVK/MoltenVK/Utility/MVKConfigMembers.def
@@ -85,6 +85,7 @@ MVK_CONFIG_MEMBER(timestampPeriodLowPassAlpha,            float,
 MVK_CONFIG_MEMBER(useMetalPrivateAPI,                     VkBool32,                                 USE_METAL_PRIVATE_API)
 MVK_CONFIG_MEMBER_STRING(shaderDumpDir,                   char*,                                    SHADER_DUMP_DIR)
 MVK_CONFIG_MEMBER(shaderLogEstimatedGLSL,                 VkBool32,                                 SHADER_LOG_ESTIMATED_GLSL)
+MVK_CONFIG_MEMBER(enable2DViewOf3D,                       VkBool32,                                 ENABLE_2DVIEWOF3D)
 
 #undef MVK_CONFIG_MEMBER
 #undef MVK_CONFIG_MEMBER_STRING

diff --git a/MoltenVK/MoltenVK/Utility/MVKEnvironment.cpp b/MoltenVK/MoltenVK/Utility/MVKEnvironment.cpp
@@ -26,10 +26,9 @@
 // Return the expected size of MVKConfiguration, based on contents of MVKConfigMembers.def.
 static constexpr uint32_t getExpectedMVKConfigurationSize() {
 #define MVK_CONFIG_MEMBER(member, mbrType, name)         cfgSize += sizeof(mbrType);
-	uint32_t cfgSize = 0;
+	size_t cfgSize = 0;
 #include "MVKConfigMembers.def"
-	cfgSize += kMVKConfigurationInternalPaddingByteCount;
-	return cfgSize;
+	return (uint32_t)((cfgSize + (alignof(MVKConfiguration) - 1)) & ~(alignof(MVKConfiguration) - 1));
 }
 
 // Return the expected number of string members in MVKConfiguration, based on contents of MVKConfigMembers.def.

diff --git a/MoltenVK/MoltenVK/Utility/MVKEnvironment.h b/MoltenVK/MoltenVK/Utility/MVKEnvironment.h
@@ -370,3 +370,7 @@ void mvkSetConfig(MVKConfiguration& dstMVKConfig, const MVKConfiguration& srcMVK
 #	define MVK_CONFIG_SHADER_LOG_ESTIMATED_GLSL		0
 #endif
 
+/** Advertise VK_EXT_image_2d_view_of_3d */
+#ifndef MVK_CONFIG_ENABLE_2DVIEWOF3D
+#   define MVK_CONFIG_ENABLE_2DVIEWOF3D  0
+#endif