Vulkan.Extensions.VK_KHR_fragment_shading_rate

vkCmdSetFragmentShadingRateKHR - Set pipeline fragment shading rate and combiner operation dynamically for a command buffer

Description

This command sets the pipeline fragment shading rate and combiner operation for subsequent drawing commands when drawing using shader objects, or when the graphics pipeline is created with DYNAMIC_STATE_FRAGMENT_SHADING_RATE_KHR set in PipelineDynamicStateCreateInfo::pDynamicStates. Otherwise, this state is specified by the PipelineFragmentShadingRateStateCreateInfoKHR values used to create the currently active pipeline.

Valid Usage

• If the pipelineFragmentShadingRate feature is not enabled, pFragmentSize->width must be 1

• If the pipelineFragmentShadingRate feature is not enabled, pFragmentSize->height must be 1

• One of the pipelineFragmentShadingRate, primitiveFragmentShadingRate, or attachmentFragmentShadingRate features must be enabled

• If the primitiveFragmentShadingRate feature is not enabled, combinerOps[0] must be FRAGMENT_SHADING_RATE_COMBINER_OP_KEEP_KHR

• If the attachmentFragmentShadingRate feature is not enabled, combinerOps[1] must be FRAGMENT_SHADING_RATE_COMBINER_OP_KEEP_KHR

• If the fragmentSizeNonTrivialCombinerOps limit is not supported, elements of combinerOps must be either FRAGMENT_SHADING_RATE_COMBINER_OP_KEEP_KHR or FRAGMENT_SHADING_RATE_COMBINER_OP_REPLACE_KHR

• pFragmentSize->width must be greater than or equal to 1

• pFragmentSize->height must be greater than or equal to 1

• pFragmentSize->width must be a power-of-two value

• pFragmentSize->height must be a power-of-two value

• pFragmentSize->width must be less than or equal to 4

• pFragmentSize->height must be less than or equal to 4

Valid Usage (Implicit)

• commandBuffer must be a valid CommandBuffer handle

• pFragmentSize must be a valid pointer to a valid Extent2D structure

• Each element of combinerOps must be a valid FragmentShadingRateCombinerOpKHR value

• commandBuffer must be in the recording state

• The CommandPool that commandBuffer was allocated from must support QUEUE_GRAPHICS_BIT operations

• This command must only be called outside of a video coding scope

Host Synchronization

• Host access to commandBuffer must be externally synchronized

• Host access to the CommandPool that commandBuffer was allocated from must be externally synchronized

Command Properties

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Conditional Rendering

vkCmdSetFragmentShadingRateKHR is not affected by conditional rendering

See Also

VK_KHR_fragment_shading_rate, CommandBuffer, Extent2D, FragmentShadingRateCombinerOpKHR

vkGetPhysicalDeviceFragmentShadingRatesKHR - Get available shading rates for a physical device

Description

If pFragmentShadingRates is NULL, then the number of fragment shading rates available is returned in pFragmentShadingRateCount. Otherwise, pFragmentShadingRateCount must point to a variable set by the application to the number of elements in the pFragmentShadingRates array, and on return the variable is overwritten with the number of structures actually written to pFragmentShadingRates. If pFragmentShadingRateCount is less than the number of fragment shading rates available, at most pFragmentShadingRateCount structures will be written, and INCOMPLETE will be returned instead of SUCCESS, to indicate that not all the available fragment shading rates were returned.

The returned array of fragment shading rates must be ordered from largest fragmentSize.width value to smallest, and each set of fragment shading rates with the same fragmentSize.width value must be ordered from largest fragmentSize.height to smallest. Any two entries in the array must not have the same fragmentSize values.

For any entry in the array, the following rules also apply:

• The value of fragmentSize.width must be less than or equal to maxFragmentSize.width.

• The value of fragmentSize.width must be greater than or equal to 1.

• The value of fragmentSize.width must be a power-of-two.

• The value of fragmentSize.height must be less than or equal to maxFragmentSize.height.

• The value of fragmentSize.height must be greater than or equal to 1.

• The value of fragmentSize.height must be a power-of-two.

• The highest sample count in sampleCounts must be less than or equal to maxFragmentShadingRateRasterizationSamples.

• The product of fragmentSize.width, fragmentSize.height, and the highest sample count in sampleCounts must be less than or equal to maxFragmentShadingRateCoverageSamples.

Implementations must support at least the following shading rates:

If framebufferColorSampleCounts, includes SAMPLE_COUNT_2_BIT, the required rates must also include SAMPLE_COUNT_2_BIT.

Including the {1,1} fragment size is done for completeness; it has no actual effect on the support of rendering without setting the fragment size. All sample counts and render pass transforms are supported for this rate.

The returned set of fragment shading rates must be returned in the native (rotated) coordinate system. For rasterization using render pass transform not equal to SURFACE_TRANSFORM_IDENTITY_BIT_KHR, the application must transform the returned fragment shading rates into the current (unrotated) coordinate system to get the supported rates for that transform.

For example, consider an implementation returning support for 4x2, but not 2x4 in the set of supported fragment shading rates. This means that for transforms SURFACE_TRANSFORM_ROTATE_90_BIT_KHR and SURFACE_TRANSFORM_ROTATE_270_BIT_KHR, 2x4 is a supported rate, but 4x2 is an unsupported rate.

Valid Usage (Implicit)

• physicalDevice must be a valid PhysicalDevice handle

• pFragmentShadingRateCount must be a valid pointer to a uint32_t value

• If the value referenced by pFragmentShadingRateCount is not 0, and pFragmentShadingRates is not NULL, pFragmentShadingRates must be a valid pointer to an array of pFragmentShadingRateCount PhysicalDeviceFragmentShadingRateKHR structures

Return Codes

Success

• INCOMPLETE

• SUCCESS

Failure

• ERROR_OUT_OF_HOST_MEMORY

• ERROR_UNKNOWN

• ERROR_VALIDATION_FAILED

See Also

VK_KHR_fragment_shading_rate, PhysicalDevice, PhysicalDeviceFragmentShadingRateKHR

VkFragmentShadingRateAttachmentInfoKHR - Structure specifying a fragment shading rate attachment for a subpass

Description

If no shading rate attachment is specified, or if this structure is not specified, the implementation behaves as if a valid shading rate attachment was specified with all texels specifying a single pixel per fragment.

Valid Usage

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, its layout member must be equal to IMAGE_LAYOUT_GENERAL or IMAGE_LAYOUT_FRAGMENT_SHADING_RATE_ATTACHMENT_OPTIMAL_KHR

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.width must be a power of two value

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.width must be less than or equal to maxFragmentShadingRateAttachmentTexelSize.width

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.width must be greater than or equal to minFragmentShadingRateAttachmentTexelSize.width

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.height must be a power of two value

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.height must be less than or equal to maxFragmentShadingRateAttachmentTexelSize.height

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, shadingRateAttachmentTexelSize.height must be greater than or equal to minFragmentShadingRateAttachmentTexelSize.height

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, the quotient of shadingRateAttachmentTexelSize.width and shadingRateAttachmentTexelSize.height must be less than or equal to maxFragmentShadingRateAttachmentTexelSizeAspectRatio

• If pFragmentShadingRateAttachment is not NULL and its attachment member is not ATTACHMENT_UNUSED, the quotient of shadingRateAttachmentTexelSize.height and shadingRateAttachmentTexelSize.width must be less than or equal to maxFragmentShadingRateAttachmentTexelSizeAspectRatio

Valid Usage (Implicit)

• sType must be STRUCTURE_TYPE_FRAGMENT_SHADING_RATE_ATTACHMENT_INFO_KHR

• If pFragmentShadingRateAttachment is not NULL, pFragmentShadingRateAttachment must be a valid pointer to a valid AttachmentReference2 structure

Structure Chaining

Extends the structure

• SubpassDescription2

See Also

VK_KHR_fragment_shading_rate, AttachmentReference2, Extent2D, StructureType

VkPipelineFragmentShadingRateStateCreateInfoKHR - Structure specifying parameters controlling the fragment shading rate

Description

If the pNext chain of GraphicsPipelineCreateInfo includes a PipelineFragmentShadingRateStateCreateInfoKHR structure, then that structure includes parameters controlling the pipeline fragment shading rate.

If this structure is not present, fragmentSize is considered to be equal to (1,1), and both elements of combinerOps are considered to be equal to FRAGMENT_SHADING_RATE_COMBINER_OP_KEEP_KHR.

Structure Chaining

Extends the structure

• GraphicsPipelineCreateInfo

See Also

VK_KHR_fragment_shading_rate, Extent2D, FragmentShadingRateCombinerOpKHR, StructureType

VkPhysicalDeviceFragmentShadingRateFeaturesKHR - Structure indicating support for variable rate fragment shading

Members

This structure describes the following features:

Description

If the PhysicalDeviceFragmentShadingRateFeaturesKHR structure is included in the pNext chain of the PhysicalDeviceFeatures2 structure passed to getPhysicalDeviceFeatures2, it is filled in to indicate whether each corresponding feature is supported. If the application wishes to use a Device with any features described by PhysicalDeviceFragmentShadingRateFeaturesKHR, it must add an instance of the structure, with the desired feature members set to TRUE, to the pNext chain of DeviceCreateInfo when creating the Device.

Structure Chaining

Extends the structures

• DeviceCreateInfo

• PhysicalDeviceFeatures2

See Also

VK_KHR_fragment_shading_rate, Bool32, StructureType

VkPhysicalDeviceFragmentShadingRatePropertiesKHR - Structure describing variable fragment shading rate limits that can be supported by an implementation

Description

Multiplication of the combiner rates using the fragment width/height in linear space is equivalent to an addition of those values in log2 space. Some implementations inadvertently implemented an addition in linear space due to unclear requirements originating outside of this specification. This resulted in fragmentShadingRateStrictMultiplyCombiner being added. Fortunately, this only affects situations where a rate of 1 in either dimension is combined with another rate of 1. All other combinations result in the exact same result as if multiplication was performed in linear space due to the clamping logic, and the fact that both the sum and product of 2 and 2 are equal. In many cases, this limit will not affect the correct operation of applications.

If the PhysicalDeviceFragmentShadingRatePropertiesKHR structure is included in the pNext chain of the PhysicalDeviceProperties2 structure passed to getPhysicalDeviceProperties2, it is filled in with each corresponding implementation-dependent property.

These properties are related to fragment shading rates.

Structure Chaining

Extends the structure

• PhysicalDeviceProperties2

See Also

VK_KHR_fragment_shading_rate, Bool32, Extent2D, SampleCountFlagBits, StructureType

VkPhysicalDeviceFragmentShadingRateKHR - Structure returning information about sample count specific additional multisampling capabilities

Valid Usage (Implicit)

See Also

VK_KHR_fragment_shading_rate, Extent2D, SampleCountFlags, StructureType, getPhysicalDeviceFragmentShadingRatesKHR

VkRenderingFragmentShadingRateAttachmentInfoKHR - Structure specifying fragment shading rate attachment information

Description

This structure can be included in the pNext chain of RenderingInfo to define a fragment shading rate attachment. If imageView is NULL_HANDLE, or if this structure is not specified, the implementation behaves as if a valid shading rate attachment was specified with all texels specifying a single pixel per fragment.

Valid Usage

• If imageView is not NULL_HANDLE, layout must be IMAGE_LAYOUT_GENERAL or IMAGE_LAYOUT_FRAGMENT_SHADING_RATE_ATTACHMENT_OPTIMAL_KHR

• If imageView is not NULL_HANDLE, it must have been created with the IMAGE_USAGE_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR usage flag set

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.width must be a power of two value

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.width must be less than or equal to maxFragmentShadingRateAttachmentTexelSize.width

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.width must be greater than or equal to minFragmentShadingRateAttachmentTexelSize.width

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.height must be a power of two value

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.height must be less than or equal to maxFragmentShadingRateAttachmentTexelSize.height

• If imageView is not NULL_HANDLE, shadingRateAttachmentTexelSize.height must be greater than or equal to minFragmentShadingRateAttachmentTexelSize.height

• If imageView is not NULL_HANDLE, the quotient of shadingRateAttachmentTexelSize.width and shadingRateAttachmentTexelSize.height must be less than or equal to maxFragmentShadingRateAttachmentTexelSizeAspectRatio

• If imageView is not NULL_HANDLE, the quotient of shadingRateAttachmentTexelSize.height and shadingRateAttachmentTexelSize.width must be less than or equal to maxFragmentShadingRateAttachmentTexelSizeAspectRatio

Valid Usage (Implicit)

• sType must be STRUCTURE_TYPE_RENDERING_FRAGMENT_SHADING_RATE_ATTACHMENT_INFO_KHR

• If imageView is not NULL_HANDLE, imageView must be a valid ImageView handle

• imageLayout must be a valid ImageLayout value

Structure Chaining

Extends the structure

• RenderingInfo

See Also

VK_KHR_dynamic_rendering, VK_KHR_fragment_shading_rate, VK_VERSION_1_3, Extent2D, ImageLayout, ImageView, StructureType

VkFragmentShadingRateCombinerOpKHR - Control how fragment shading rates are combined

Description

• FRAGMENT_SHADING_RATE_COMBINER_OP_KEEP_KHR specifies a combiner operation of combine(Axy,Bxy) = Axy.

• FRAGMENT_SHADING_RATE_COMBINER_OP_REPLACE_KHR specifies a combiner operation of combine(Axy,Bxy) = Bxy.

• FRAGMENT_SHADING_RATE_COMBINER_OP_MIN_KHR specifies a combiner operation of combine(Axy,Bxy) = min(Axy,Bxy).

• FRAGMENT_SHADING_RATE_COMBINER_OP_MAX_KHR specifies a combiner operation of combine(Axy,Bxy) = max(Axy,Bxy).

• FRAGMENT_SHADING_RATE_COMBINER_OP_MUL_KHR specifies a combiner operation of combine(Axy,Bxy) = Axy*Bxy.

where combine(Axy,Bxy) is the combine operation, and Axy and Bxy are the inputs to the operation.

If fragmentShadingRateStrictMultiplyCombiner is FALSE, using FRAGMENT_SHADING_RATE_COMBINER_OP_MUL_KHR with values of 1 for both A and B in the same dimension results in the value 2 being produced for that dimension. See the definition of fragmentShadingRateStrictMultiplyCombiner for more information.

These operations are performed in a component-wise fashion.

See Also

VK_KHR_fragment_shading_rate, PipelineFragmentShadingRateEnumStateCreateInfoNV, PipelineFragmentShadingRateStateCreateInfoKHR, cmdSetFragmentShadingRateEnumNV, cmdSetFragmentShadingRateKHR