- Last Modified Date
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2020-04-03
- Revision
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2
- IP Status
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No known IP claims.
- Dependencies
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This extension is written against version 1.0 of the Vulkan API.
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Requires elink:VkObjectType
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- Contributors
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Mark Young, LunarG
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Baldur Karlsson
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Ian Elliott, Google
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Courtney Goeltzenleuchter, Google
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Karl Schultz, LunarG
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Mark Lobodzinski, LunarG
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Mike Schuchardt, LunarG
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Jaakko Konttinen, AMD
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Dan Ginsburg, Valve Software
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Rolando Olivares, Epic Games
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Dan Baker, Oxide Games
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Kyle Spagnoli, NVIDIA
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Jon Ashburn, LunarG
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Piers Daniell, NVIDIA
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Due to the nature of the Vulkan interface, there is very little error
information available to the developer and application.
By using the VK_EXT_debug_utils extension, developers can: obtain more
information.
When combined with validation layers, even more detailed feedback on the
application’s use of Vulkan will be provided.
This extension provides the following capabilities:
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The ability to create a debug messenger which will pass along debug messages to an application supplied callback.
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The ability to identify specific Vulkan objects using a name or tag to improve tracking.
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The ability to identify specific sections within a sname:VkQueue or sname:VkCommandBuffer using labels to aid organization and offline analysis in external tools.
The main difference between this extension and apiext:VK_EXT_debug_report
and apiext:VK_EXT_debug_marker is that those extensions use
elink:VkDebugReportObjectTypeEXT to identify objects.
This extension uses the core elink:VkObjectType in place of
elink:VkDebugReportObjectTypeEXT.
The primary reason for this move is that no future object type handle
enumeration values will be added to elink:VkDebugReportObjectTypeEXT since
the creation of elink:VkObjectType.
In addition, this extension combines the functionality of both
apiext:VK_EXT_debug_report and apiext:VK_EXT_debug_marker by allowing
object name and debug markers (now called labels) to be returned to the
application’s callback function.
This should assist in clarifying the details of a debug message including:
what objects are involved and potentially which location within a
slink:VkQueue or slink:VkCommandBuffer the message occurred.
Example 1
VK_EXT_debug_utils allows an application to register multiple callbacks
with any Vulkan component wishing to report debug information.
Some callbacks may log the information to a file, others may cause a debug
break point or other application-defined behavior.
An application can: register callbacks even when no validation layers are
enabled, but they will only be called for loader and, if implemented, driver
events.
To capture events that occur while creating or destroying an instance an application can: link a slink:VkDebugUtilsMessengerCreateInfoEXT structure to the pname:pNext chain of the slink:VkInstanceCreateInfo structure passed to flink:vkCreateInstance.
Example uses: Create three callback objects. One will log errors and warnings to the debug console using Windows code:OutputDebugString. The second will cause the debugger to break at that callback when an error happens and the third will log warnings to stdout.
extern VkInstance instance;
VkResult res;
VkDebugUtilsMessengerEXT cb1, cb2, cb3;
// Must call extension functions through a function pointer:
PFN_vkCreateDebugUtilsMessengerEXT pfnCreateDebugUtilsMessengerEXT = (PFN_vkCreateDebugUtilsMessengerEXT)vkGetInstanceProcAddr(instance, "vkCreateDebugUtilsMessengerEXT");
PFN_vkDestroyDebugUtilsMessengerEXT pfnDestroyDebugUtilsMessengerEXT = (PFN_vkDestroyDebugUtilsMessengerEXT)vkGetInstanceProcAddr(instance, "vkDestroyDebugUtilsMessengerEXT");
VkDebugUtilsMessengerCreateInfoEXT callback1 = {
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,
.pNext = NULL,
.flags = 0,
.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT |
VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,
.messageType= VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
.pfnUserCallback = myOutputDebugString,
.pUserData = NULL
};
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, NULL, &cb1);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
callback1.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
callback1.pfnUserCallback = myDebugBreak;
callback1.pUserData = NULL;
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, NULL, &cb2);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
VkDebugUtilsMessengerCreateInfoEXT callback3 = {
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,
.pNext = NULL,
.flags = 0,
.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,
.messageType = VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
.pfnUserCallback = mystdOutLogger,
.pUserData = NULL
};
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback3, NULL, &cb3);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
...
// Remove callbacks when cleaning up
pfnDestroyDebugUtilsMessengerEXT(instance, cb1, NULL);
pfnDestroyDebugUtilsMessengerEXT(instance, cb2, NULL);
pfnDestroyDebugUtilsMessengerEXT(instance, cb3, NULL);Example 2
Associate a name with an image, for easier debugging in external tools or with validation layers that can print a friendly name when referring to objects in error messages.
extern VkInstance instance;
extern VkDevice device;
extern VkImage image;
// Must call extension functions through a function pointer:
PFN_vkSetDebugUtilsObjectNameEXT pfnSetDebugUtilsObjectNameEXT = (PFN_vkSetDebugUtilsObjectNameEXT)vkGetInstanceProcAddr(instance, "vkSetDebugUtilsObjectNameEXT");
// Set a name on the image
const VkDebugUtilsObjectNameInfoEXT imageNameInfo =
{
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT,
.pNext = NULL,
.objectType = VK_OBJECT_TYPE_IMAGE,
.objectHandle = (uint64_t)image,
.pObjectName = "Brick Diffuse Texture",
};
pfnSetDebugUtilsObjectNameEXT(device, &imageNameInfo);
// A subsequent error might print:
// Image 'Brick Diffuse Texture' (0xc0dec0dedeadbeef) is used in a
// command buffer with no memory bound to it.Example 3
Annotating regions of a workload with naming information so that offline analysis tools can display a more usable visualization of the commands submitted.
extern VkInstance instance;
extern VkCommandBuffer commandBuffer;
// Must call extension functions through a function pointer:
PFN_vkQueueBeginDebugUtilsLabelEXT pfnQueueBeginDebugUtilsLabelEXT = (PFN_vkQueueBeginDebugUtilsLabelEXT)vkGetInstanceProcAddr(instance, "vkQueueBeginDebugUtilsLabelEXT");
PFN_vkQueueEndDebugUtilsLabelEXT pfnQueueEndDebugUtilsLabelEXT = (PFN_vkQueueEndDebugUtilsLabelEXT)vkGetInstanceProcAddr(instance, "vkQueueEndDebugUtilsLabelEXT");
PFN_vkCmdBeginDebugUtilsLabelEXT pfnCmdBeginDebugUtilsLabelEXT = (PFN_vkCmdBeginDebugUtilsLabelEXT)vkGetInstanceProcAddr(instance, "vkCmdBeginDebugUtilsLabelEXT");
PFN_vkCmdEndDebugUtilsLabelEXT pfnCmdEndDebugUtilsLabelEXT = (PFN_vkCmdEndDebugUtilsLabelEXT)vkGetInstanceProcAddr(instance, "vkCmdEndDebugUtilsLabelEXT");
PFN_vkCmdInsertDebugUtilsLabelEXT pfnCmdInsertDebugUtilsLabelEXT = (PFN_vkCmdInsertDebugUtilsLabelEXT)vkGetInstanceProcAddr(instance, "vkCmdInsertDebugUtilsLabelEXT");
// Describe the area being rendered
const VkDebugUtilsLabelEXT houseLabel =
{
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT,
.pNext = NULL,
.pLabelName = "Brick House",
.color = { 1.0f, 0.0f, 0.0f, 1.0f },
};
// Start an annotated group of calls under the 'Brick House' name
pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &houseLabel);
{
// A mutable structure for each part being rendered
VkDebugUtilsLabelEXT housePartLabel =
{
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT,
.pNext = NULL,
.pLabelName = NULL,
.color = { 0.0f, 0.0f, 0.0f, 0.0f },
};
// Set the name and insert the marker
housePartLabel.pLabelName = "Walls";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
// Insert the drawcall for the walls
vkCmdDrawIndexed(commandBuffer, 1000, 1, 0, 0, 0);
// Insert a recursive region for two sets of windows
housePartLabel.pLabelName = "Windows";
pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
{
vkCmdDrawIndexed(commandBuffer, 75, 6, 1000, 0, 0);
vkCmdDrawIndexed(commandBuffer, 100, 2, 1450, 0, 0);
}
pfnCmdEndDebugUtilsLabelEXT(commandBuffer);
housePartLabel.pLabelName = "Front Door";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
vkCmdDrawIndexed(commandBuffer, 350, 1, 1650, 0, 0);
housePartLabel.pLabelName = "Roof";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
vkCmdDrawIndexed(commandBuffer, 500, 1, 2000, 0, 0);
}
// End the house annotation started above
pfnCmdEndDebugUtilsLabelEXT(commandBuffer);
// Do other work
vkEndCommandBuffer(commandBuffer);
// Describe the queue being used
const VkDebugUtilsLabelEXT queueLabel =
{
.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT,
.pNext = NULL,
.pLabelName = "Main Render Work",
.color = { 0.0f, 1.0f, 0.0f, 1.0f },
};
// Identify the queue label region
pfnQueueBeginDebugUtilsLabelEXT(queue, &queueLabel);
// Submit the work for the main render thread
const VkCommandBuffer cmd_bufs[] = {commandBuffer};
VkSubmitInfo submit_info =
{
.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
.pNext = NULL,
.waitSemaphoreCount = 0,
.pWaitSemaphores = NULL,
.pWaitDstStageMask = NULL,
.commandBufferCount = 1,
.pCommandBuffers = cmd_bufs,
.signalSemaphoreCount = 0,
.pSignalSemaphores = NULL
};
vkQueueSubmit(queue, 1, &submit_info, fence);
// End the queue label region
pfnQueueEndDebugUtilsLabelEXT(queue);1) Should we just name this extension VK_EXT_debug_report2
RESOLVED: No. There is enough additional changes to the structures to break backwards compatibility. So, a new name was decided that would not indicate any interaction with the previous extension.
2) Will validation layers immediately support all the new features.
RESOLVED: Not immediately.
As one can imagine, there is a lot of work involved with converting the
validation layer logging over to the new functionality.
Basic logging, as seen in the origin apiext:VK_EXT_debug_report extension
will be made available immediately.
However, adding the labels and object names will take time.
Since the priority for Khronos at this time is to continue focusing on Valid
Usage statements, it may take a while before the new functionality is fully
exposed.
3) If the validation layers will not expose the new functionality immediately, then what is the point of this extension?
RESOLVED: We needed a replacement for apiext:VK_EXT_debug_report because
the elink:VkDebugReportObjectTypeEXT enumeration will no longer be updated
and any new objects will need to be debugged using the new functionality
provided by this extension.
4) Should this extension be split into two separate parts (1 extension that is an instance extension providing the callback functionality, and another device extension providing the general debug marker and annotation functionality)?
RESOLVED: No, the functionality for this extension is too closely related. If we did split up the extension, where would the structures and enums live, and how would you define that the device behavior in the instance extension is really only valid if the device extension is enabled, and the functionality is passed in. It is cleaner to just define this all as an instance extension, plus it allows the application to enable all debug functionality provided with one enable string during flink:vkCreateInstance.
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Revision 1, 2017-09-14 (Mark Young and all listed Contributors)
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Initial draft, based on
apiext:VK_EXT_debug_reportandapiext:VK_EXT_debug_markerin addition to previous feedback supplied from various companies including Valve, Epic, and Oxide games.
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Revision 2, 2020-04-03 (Mark Young and Piers Daniell)
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Updated to allow either
NULLor an empty string to be passed in for pname:pObjectName in sname:VkDebugUtilsObjectNameInfoEXT, because the loader and various drivers supportNULLalready.
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