// Copyright (c) 2014-2017 Khronos Group. This work is licensed under a // Creative Commons Attribution 4.0 International License; see // http://creativecommons.org/licenses/by/4.0/ [[display,display]] == Presenting Directly to Display Devices In some environments applications can: also present Vulkan rendering directly to display devices without using an intermediate windowing system. This can: be useful for embedded applications, or implementing the rendering/presentation backend of a windowing system using Vulkan. The +VK_KHR_display+ extension provides the functionality necessary to enumerate display devices and create sname:VkSurfaceKHR objects that target displays. === Display Enumeration [open,refpage='VkDisplayKHR',desc='Opaque handle to a display object',type='handles'] -- Displays are represented by sname:VkDisplayKHR handles: include::../../api/handles/VkDisplayKHR.txt[] -- [open,refpage='vkGetPhysicalDeviceDisplayPropertiesKHR',desc='Query information about the available displays',type='protos'] -- Various functions are provided for enumerating the available display devices present on a Vulkan physical device. To query information about the available displays, call: include::../../api/protos/vkGetPhysicalDeviceDisplayPropertiesKHR.txt[] * pname:physicalDevice is a physical device. * pname:pPropertyCount is a pointer to an integer related to the number of display devices available or queried, as described below. * pname:pProperties is either `NULL` or a pointer to an array of sname:VkDisplayPropertiesKHR structures. If pname:pProperties is `NULL`, then the number of display devices available for pname:physicalDevice is returned in pname:pPropertyCount. Otherwise, pname:pPropertyCount must: point to a variable set by the user to the number of elements in the pname:pProperties array, and on return the variable is overwritten with the number of structures actually written to pname:pProperties. If the value of pname:pPropertyCount is less than the number of display devices for pname:physicalDevice, at most pname:pPropertyCount structures will be written. If pname:pPropertyCount is smaller than the number of display devices available for pname:physicalDevice, ename:VK_INCOMPLETE will be returned instead of ename:VK_SUCCESS to indicate that not all the available values were returned. include::../../validity/protos/vkGetPhysicalDeviceDisplayPropertiesKHR.txt[] -- [open,refpage='VkDisplayPropertiesKHR',desc='Structure describing an available display device',type='structs'] -- The sname:VkDisplayPropertiesKHR structure is defined as: include::../../api/structs/VkDisplayPropertiesKHR.txt[] * pname:display is a handle that is used to refer to the display described here. This handle will be valid for the lifetime of the Vulkan instance. * pname:displayName is a pointer to a NULL-terminated string containing the name of the display. Generally, this will be the name provided by the display's EDID. It can: be `NULL` if no suitable name is available. If not `NULL`, the memory it points to must: remain accessible as long as pname:display is valid. * pname:physicalDimensions describes the physical width and height of the visible portion of the display, in millimeters. * pname:physicalResolution describes the physical, native, or preferred resolution of the display. [NOTE] .Note ==== For devices which have no natural value to return here, implementations should: return the maximum resolution supported. ==== * pname:supportedTransforms tells which transforms are supported by this display. This will contain one or more of the bits from sname:VkSurfaceTransformFlagsKHR. * pname:planeReorderPossible tells whether the planes on this display can: have their z order changed. If this is ename:VK_TRUE, the application can: re-arrange the planes on this display in any order relative to each other. * pname:persistentContent tells whether the display supports self-refresh/internal buffering. If this is true, the application can: submit persistent present operations on swapchains created against this display. [NOTE] .Note ==== Persistent presents may: have higher latency, and may: use less power when the screen content is updated infrequently, or when only a portion of the screen needs to be updated in most frames. ==== include::../../validity/structs/VkDisplayPropertiesKHR.txt[] -- ifdef::VK_EXT_direct_mode_display[] include::../VK_EXT_direct_mode_display/acquire_release_displays.txt[] endif::VK_EXT_direct_mode_display[] ==== Display Planes [open,refpage='vkGetPhysicalDeviceDisplayPlanePropertiesKHR',desc='Query the plane properties',type='protos'] -- Images are presented to individual planes on a display. Devices must: support at least one plane on each display. Planes can: be stacked and blended to composite multiple images on one display. Devices may: support only a fixed stacking order and fixed mapping between planes and displays, or they may: allow arbitrary application specified stacking orders and mappings between planes and displays. To query the properties of device display planes, call: include::../../api/protos/vkGetPhysicalDeviceDisplayPlanePropertiesKHR.txt[] * pname:physicalDevice is a physical device. * pname:pPropertyCount is a pointer to an integer related to the number of display planes available or queried, as described below. * pname:pProperties is either `NULL` or a pointer to an array of sname:VkDisplayPlanePropertiesKHR structures. If pname:pProperties is `NULL`, then the number of display planes available for pname:physicalDevice is returned in pname:pPropertyCount. Otherwise, pname:pPropertyCount must: point to a variable set by the user to the number of elements in the pname:pProperties array, and on return the variable is overwritten with the number of structures actually written to pname:pProperties. If the value of pname:pPropertyCount is less than the number of display planes for pname:physicalDevice, at most pname:pPropertyCount structures will be written. include::../../validity/protos/vkGetPhysicalDeviceDisplayPlanePropertiesKHR.txt[] -- [open,refpage='VkDisplayPlanePropertiesKHR',desc='Structure describing display plane properties',type='structs'] -- The sname:VkDisplayPlanePropertiesKHR structure is defined as: include::../../api/structs/VkDisplayPlanePropertiesKHR.txt[] * pname:currentDisplay is the handle of the display the plane is currently associated with. If the plane is not currently attached to any displays, this will be sname:VK_NULL_HANDLE. * pname:currentStackIndex is the current z-order of the plane. This will be between 0 and the value returned by fname:vkGetPhysicalDeviceDisplayPlanePropertiesKHR() in pname:pPropertyCount. include::../../validity/structs/VkDisplayPlanePropertiesKHR.txt[] -- [open,refpage='vkGetDisplayPlaneSupportedDisplaysKHR',desc='Query the list of displays a plane supports',type='protos'] -- To determine which displays a plane is usable with, call include::../../api/protos/vkGetDisplayPlaneSupportedDisplaysKHR.txt[] * pname:physicalDevice is a physical device. * pname:planeIndex is the plane which the application wishes to use, and must: be in the range [eq]#[0, physical device plane count - 1]#. * pname:pDisplayCount is a pointer to an integer related to the number of displays available or queried, as described below. * pname:pDisplays is either `NULL` or a pointer to an array of sname:VkDisplayKHR handles. If pname:pDisplays is `NULL`, then the number of displays usable with the specified pname:planeIndex for pname:physicalDevice is returned in pname:pDisplayCount. Otherwise, pname:pDisplayCount must: point to a variable set by the user to the number of elements in the pname:pDisplays array, and on return the variable is overwritten with the number of handles actually written to pname:pDisplays. If the value of pname:pDisplayCount is less than the number of display planes for pname:physicalDevice, at most pname:pDisplayCount handles will be written. If pname:pDisplayCount is smaller than the number of displays usable with the specified pname:planeIndex for pname:physicalDevice, ename:VK_INCOMPLETE will be returned instead of ename:VK_SUCCESS to indicate that not all the available values were returned. .Valid Usage **** * [[VUID-vkGetDisplayPlaneSupportedDisplaysKHR-planeIndex-01249]] pname:planeIndex must: be less than the number of display planes supported by the device as determined by calling fname:vkGetPhysicalDeviceDisplayPlanePropertiesKHR **** include::../../validity/protos/vkGetDisplayPlaneSupportedDisplaysKHR.txt[] -- Additional properties of displays are queried using specialized query functions. ==== Display Modes [open,refpage='VkDisplayModeKHR',desc='Opaque handle to a display mode object',type='handles'] -- Display modes are represented by sname:VkDisplayModeKHR handles: include::../../api/handles/VkDisplayModeKHR.txt[] -- [open,refpage='vkGetDisplayModePropertiesKHR',desc='Query the set of mode properties supported by the display',type='protos'] -- Each display has one or more supported modes associated with it by default. These built-in modes are queried by calling: include::../../api/protos/vkGetDisplayModePropertiesKHR.txt[] * pname:physicalDevice is the physical device associated with pname:display. * pname:display is the display to query. * pname:pPropertyCount is a pointer to an integer related to the number of display modes available or queried, as described below. * pname:pProperties is either `NULL` or a pointer to an array of sname:VkDisplayModePropertiesKHR structures. If pname:pProperties is `NULL`, then the number of display modes available on the specified pname:display for pname:physicalDevice is returned in pname:pPropertyCount. Otherwise, pname:pPropertyCount must: point to a variable set by the user to the number of elements in the pname:pProperties array, and on return the variable is overwritten with the number of structures actually written to pname:pProperties. If the value of pname:pPropertyCount is less than the number of display modes for pname:physicalDevice, at most pname:pPropertyCount structures will be written. If pname:pPropertyCount is smaller than the number of display modes available on the specified pname:display for pname:physicalDevice, ename:VK_INCOMPLETE will be returned instead of ename:VK_SUCCESS to indicate that not all the available values were returned. include::../../validity/protos/vkGetDisplayModePropertiesKHR.txt[] -- [open,refpage='VkDisplayModePropertiesKHR',desc='Structure describing display mode properties',type='structs'] -- The sname:VkDisplayModePropertiesKHR structure is defined as: include::../../api/structs/VkDisplayModePropertiesKHR.txt[] * pname:displayMode is a handle to the display mode described in this structure. This handle will be valid for the lifetime of the Vulkan instance. * pname:parameters is a sname:VkDisplayModeParametersKHR structure describing the display parameters associated with pname:displayMode. include::../../validity/structs/VkDisplayModePropertiesKHR.txt[] -- [open,refpage='VkDisplayModeParametersKHR',desc='Structure describing display parameters associated with a display mode',type='structs'] -- The sname:VkDisplayModeParametersKHR structure is defined as: include::../../api/structs/VkDisplayModeParametersKHR.txt[] * pname:visibleRegion is the 2D extents of the visible region. * pname:refreshRate is a code:uint32_t that is the number of times the display is refreshed each second multiplied by 1000. [NOTE] .Note ==== For example, a 60Hz display mode would report a pname:refreshRate of 60,000. ==== include::../../validity/structs/VkDisplayModeParametersKHR.txt[] -- [open,refpage='vkCreateDisplayModeKHR',desc='Create a display mode',type='protos'] -- Additional modes may: also be created by calling: include::../../api/protos/vkCreateDisplayModeKHR.txt[] * pname:physicalDevice is the physical device associated with pname:display. * pname:display is the display to create an additional mode for. * pname:pCreateInfo is a slink:VkDisplayModeCreateInfoKHR structure describing the new mode to create. * pname:pAllocator is the allocator used for host memory allocated for the display mode object when there is no more specific allocator available (see <>). * pname:pMode returns the handle of the mode created. include::../../validity/protos/vkCreateDisplayModeKHR.txt[] -- [open,refpage='VkDisplayModeCreateInfoKHR',desc='Structure specifying parameters of a newly created display mode object',type='structs'] -- The sname:VkDisplayModeCreateInfoKHR structure is defined as: include::../../api/structs/VkDisplayModeCreateInfoKHR.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:flags is reserved for future use, and must: be zero. * pname:parameters is a sname:VkDisplayModeParametersKHR structure describing the display parameters to use in creating the new mode. If the parameters are not compatible with the specified display, the implementation must: return ename:VK_ERROR_INITIALIZATION_FAILED. .Valid Usage **** * [[VUID-VkDisplayModeCreateInfoKHR-width-01250]] The pname:width and pname:height members of the pname:visibleRegion member of pname:parameters must: be greater than `0` * [[VUID-VkDisplayModeCreateInfoKHR-refreshRate-01251]] The pname:refreshRate member of pname:parameters must: be greater than `0` **** include::../../validity/structs/VkDisplayModeCreateInfoKHR.txt[] -- [open,refpage='vkGetDisplayPlaneCapabilitiesKHR',desc='Query capabilities of a mode and plane combination',type='protos'] -- Applications that wish to present directly to a display must: select which layer, or "plane" of the display they wish to target, and a mode to use with the display. Each display supports at least one plane. The capabilities of a given mode and plane combination are determined by calling: include::../../api/protos/vkGetDisplayPlaneCapabilitiesKHR.txt[] * pname:physicalDevice is the physical device associated with pname:display * pname:mode is the display mode the application intends to program when using the specified plane. Note this parameter also implicitly specifies a display. * pname:planeIndex is the plane which the application intends to use with the display, and is less than the number of display planes supported by the device. * pname:pCapabilities is a pointer to a slink:VkDisplayPlaneCapabilitiesKHR structure in which the capabilities are returned. include::../../validity/protos/vkGetDisplayPlaneCapabilitiesKHR.txt[] -- [open,refpage='VkDisplayPlaneCapabilitiesKHR',desc='Structure describing capabilities of a mode and plane combination',type='structs'] -- The sname:VkDisplayPlaneCapabilitiesKHR structure is defined as: include::../../api/structs/VkDisplayPlaneCapabilitiesKHR.txt[] * pname:supportedAlpha is a bitmask of elink:VkDisplayPlaneAlphaFlagBitsKHR describing the supported alpha blending modes. * pname:minSrcPosition is the minimum source rectangle offset supported by this plane using the specified mode. * pname:maxSrcPosition is the maximum source rectangle offset supported by this plane using the specified mode. The pname:x and pname:y components of pname:maxSrcPosition must: each be greater than or equal to the pname:x and pname:y components of pname:minSrcPosition, respectively. * pname:minSrcExtent is the minimum source rectangle size supported by this plane using the specified mode. * pname:maxSrcExtent is the maximum source rectangle size supported by this plane using the specified mode. * pname:minDstPosition, pname:maxDstPosition, pname:minDstExtent, pname:maxDstExtent all have similar semantics to their corresponding "Src" equivalents, but apply to the output region within the mode rather than the input region within the source image. Unlike the "Src" offsets, pname:minDstPosition and pname:maxDstPosition may: contain negative values. The minimum and maximum position and extent fields describe the hardware limits, if any, as they apply to the specified display mode and plane. Vendors may: support displaying a subset of a swapchain's presentable images on the specified display plane. This is expressed by returning pname:minSrcPosition, pname:maxSrcPosition, pname:minSrcExtent, and pname:maxSrcExtent values that indicate a range of possible positions and sizes may: be used to specify the region within the presentable images that source pixels will be read from when creating a swapchain on the specified display mode and plane. Vendors may: also support mapping the presentable images' content to a subset or superset of the visible region in the specified display mode. This is expressed by returning pname:minDstPosition, pname:maxDstPosition, pname:minDstExtent and pname:maxDstExtent values that indicate a range of possible positions and sizes may: be used to describe the region within the display mode that the source pixels will be mapped to. Other vendors may: support only a 1-1 mapping between pixels in the presentable images and the display mode. This may: be indicated by returning [eq]#(0,0)# for pname:minSrcPosition, pname:maxSrcPosition, pname:minDstPosition, and pname:maxDstPosition, and (display mode width, display mode height) for pname:minSrcExtent, pname:maxSrcExtent, pname:minDstExtent, and pname:maxDstExtent. These values indicate the limits of the hardware's individual fields. Not all combinations of values within the offset and extent ranges returned in sname:VkDisplayPlaneCapabilitiesKHR are guaranteed to be supported. Vendors may: still fail presentation requests that specify unsupported combinations. include::../../validity/structs/VkDisplayPlaneCapabilitiesKHR.txt[] -- ifdef::VK_EXT_display_control[] include::../VK_EXT_display_control/display_control.txt[] endif::VK_EXT_display_control[] [[wsi-display-surfaces]] === Display Surfaces [open,refpage='vkCreateDisplayPlaneSurfaceKHR',desc='Create a slink:VkSurfaceKHR structure representing a display plane and mode',type='protos'] -- A complete display configuration includes a mode, one or more display planes and any parameters describing their behavior, and parameters describing some aspects of the images associated with those planes. Display surfaces describe the configuration of a single plane within a complete display configuration. To create a sname:VkSurfaceKHR structure for a display surface, call: include::../../api/protos/vkCreateDisplayPlaneSurfaceKHR.txt[] * pname:instance is the instance corresponding to the physical device the targeted display is on. * pname:pCreateInfo is a pointer to an instance of the slink:VkDisplaySurfaceCreateInfoKHR structure specifying which mode, plane, and other parameters to use, as described below. * pname:pAllocator is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see <>). * pname:pSurface points to a sname:VkSurfaceKHR handle in which the created surface is returned. include::../../validity/protos/vkCreateDisplayPlaneSurfaceKHR.txt[] -- [open,refpage='VkDisplaySurfaceCreateInfoKHR',desc='Structure specifying parameters of a newly created display plane surface object',type='structs'] -- The sname:VkDisplaySurfaceCreateInfoKHR structure is defined as: include::../../api/structs/VkDisplaySurfaceCreateInfoKHR.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:flags is reserved for future use, and must: be zero. * pname:displayMode is a slink:VkDisplayModeKHR handle specifying the mode to use when displaying this surface. * pname:planeIndex is the plane on which this surface appears. * pname:planeStackIndex is the z-order of the plane. * pname:transform is a elink:VkSurfaceTransformFlagBitsKH value specifying the transformation to apply to images as part of the scanout operation. * pname:globalAlpha is the global alpha value. This value is ignored if pname:alphaMode is not ename:VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR. * pname:alphaMode is a elink:VkDisplayPlaneAlphaFlagBitsKHR value specifying the type of alpha blending to use. * pname:imageExtent The size of the presentable images to use with the surface. [NOTE] .Note ==== Creating a display surface must: not modify the state of the displays, planes, or other resources it names. For example, it must: not apply the specified mode to be set on the associated display. Application of display configuration occurs as a side effect of presenting to a display surface. ==== .Valid Usage **** * [[VUID-VkDisplaySurfaceCreateInfoKHR-planeIndex-01252]] pname:planeIndex must: be less than the number of display planes supported by the device as determined by calling fname:vkGetPhysicalDeviceDisplayPlanePropertiesKHR * [[VUID-VkDisplaySurfaceCreateInfoKHR-planeReorderPossible-01253]] If the pname:planeReorderPossible member of the sname:VkDisplayPropertiesKHR structure returned by fname:vkGetPhysicalDeviceDisplayPropertiesKHR for the display corresponding to pname:displayMode is ename:VK_TRUE then pname:planeStackIndex must: be less than the number of display planes supported by the device as determined by calling fname:vkGetPhysicalDeviceDisplayPlanePropertiesKHR; otherwise pname:planeStackIndex must: equal the pname:currentStackIndex member of sname:VkDisplayPlanePropertiesKHR returned by fname:vkGetPhysicalDeviceDisplayPlanePropertiesKHR for the display plane corresponding to pname:displayMode * [[VUID-VkDisplaySurfaceCreateInfoKHR-alphaMode-01254]] If pname:alphaMode is ename:VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR then pname:globalAlpha must: be between `0` and `1`, inclusive * [[VUID-VkDisplaySurfaceCreateInfoKHR-alphaMode-01255]] pname:alphaMode must: be `0` or one of the bits present in the pname:supportedAlpha member of sname:VkDisplayPlaneCapabilitiesKHR returned by fname:vkGetDisplayPlaneCapabilitiesKHR for the display plane corresponding to pname:displayMode * [[VUID-VkDisplaySurfaceCreateInfoKHR-width-01256]] The pname:width and pname:height members of pname:imageExtent must: be less than the pname:maxImageDimensions2D member of sname:VkPhysicalDeviceLimits **** include::../../validity/structs/VkDisplaySurfaceCreateInfoKHR.txt[] -- [open,refpage='VkDisplayPlaneAlphaFlagBitsKHR',desc='Alpha blending type',type='enums'] -- Possible values of slink:VkDisplaySurfaceCreateInfoKHR::pname:alphaMode, specifying the type of alpha blending to use on a display, are: include::../../api/enums/VkDisplayPlaneAlphaFlagBitsKHR.txt[] * ename:VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR specifies that the source image will be treated as opaque. * ename:VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR specifies that a global alpha value must: be specified that will be applied to all pixels in the source image. * ename:VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR specifies that the alpha value will be determined by the alpha channel of the source image's pixels. If the source format contains no alpha values, no blending will be applied. The source alpha values are not premultiplied into the source image's other color channels. * ename:VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_PREMULTIPLIED_BIT_KHR is equivalent to ename:VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR, except the source alpha values are assumed to be premultiplied into the source image's other color channels. --