VkImageLayout - Layout of image and image subresources

Description

The type(s) of device access supported by each layout are:

• IMAGE_LAYOUT_UNDEFINED specifies that the layout is unknown. Image memory cannot be transitioned into this layout. This layout can be used as the initialLayout member of ImageCreateInfo. This layout can be used in place of the current image layout in a layout transition, but doing so will cause the contents of the image’s memory to be undefined.
• IMAGE_LAYOUT_PREINITIALIZED specifies that an image’s memory is in a defined layout and can be populated by data, but that it has not yet been initialized by the driver. Image memory cannot be transitioned into this layout. This layout can be used as the initialLayout member of ImageCreateInfo. This layout is intended to be used as the initial layout for an image whose contents are written by the host, and hence the data can be written to memory immediately, without first executing a layout transition. Currently, IMAGE_LAYOUT_PREINITIALIZED is only useful with linear images because there is not a standard layout defined for IMAGE_TILING_OPTIMAL images.
• IMAGE_LAYOUT_GENERAL supports all types of device access, unless specified otherwise.
• IMAGE_LAYOUT_ZERO_INITIALIZED_EXT specifies that an image’s memory is in a defined layout and is zeroed, but that it has not yet been initialized by the driver. Image memory cannot be transitioned into this layout. This layout can be used as the initialLayout member of ImageCreateInfo. This layout is intended to be used as the initial layout for an image whose contents are already zeroed, either from being explicitly set to zero by an application or from being allocated with MEMORY_ALLOCATE_ZERO_INITIALIZE_BIT_EXT.
• IMAGE_LAYOUT_ATTACHMENT_OPTIMAL specifies a layout that must only be used with attachment accesses in the graphics pipeline.
• IMAGE_LAYOUT_READ_ONLY_OPTIMAL specifies a layout allowing read only access as an attachment, or in shaders as a sampled image, combined image/sampler, or input attachment.
• IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL must only be used as a color or resolve attachment in a Framebuffer. This layout is valid only for image subresources of images created with the IMAGE_USAGE_COLOR_ATTACHMENT_BIT usage flag set.
• IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read and write access as a depth/stencil attachment. It is equivalent to IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL and IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL.
• IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read only access as a depth/stencil attachment or in shaders as a sampled image, combined image/sampler, or input attachment. It is equivalent to IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL and IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL.
• IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL specifies a layout for depth/stencil format images allowing read and write access to the stencil aspect as a stencil attachment, and read only access to the depth aspect as a depth attachment or in shaders as a sampled image, combined image/sampler, or input attachment. It is equivalent to IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL and IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL.
• IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL specifies a layout for depth/stencil format images allowing read and write access to the depth aspect as a depth attachment, and read only access to the stencil aspect as a stencil attachment or in shaders as a sampled image, combined image/sampler, or input attachment. It is equivalent to IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL and IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL.
• IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL specifies a layout for the depth aspect of a depth/stencil format image allowing read and write access as a depth attachment.
• IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL specifies a layout for the depth aspect of a depth/stencil format image allowing read-only access as a depth attachment or in shaders as a sampled image, combined image/sampler, or input attachment.
• IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL specifies a layout for the stencil aspect of a depth/stencil format image allowing read and write access as a stencil attachment.
• IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL specifies a layout for the stencil aspect of a depth/stencil format image allowing read-only access as a stencil attachment or in shaders as a sampled image, combined image/sampler, or input attachment.
• IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL specifies a layout allowing read-only access in a shader as a sampled image, combined image/sampler, or input attachment. This layout is valid only for image subresources of images created with the IMAGE_USAGE_SAMPLED_BIT or IMAGE_USAGE_INPUT_ATTACHMENT_BIT usage bits enabled.
• IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL must only be used as a source image of a transfer command (see the definition of https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#synchronization-pipeline-stages-transfer). This layout is valid only for image subresources of images created with the IMAGE_USAGE_TRANSFER_SRC_BIT usage flag set.
• IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL must only be used as a destination image of a transfer command. This layout is valid only for image subresources of images created with the IMAGE_USAGE_TRANSFER_DST_BIT usage flag set.
• IMAGE_LAYOUT_PRESENT_SRC_KHR must only be used for presenting a presentable image for display.
• IMAGE_LAYOUT_SHARED_PRESENT_KHR is valid only for shared presentable images, and must be used for any usage the image supports.
• IMAGE_LAYOUT_FRAGMENT_SHADING_RATE_ATTACHMENT_OPTIMAL_KHR must only be used as a fragment shading rate attachment or shading rate image. This layout is valid only for image subresources of images created with the IMAGE_USAGE_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR usage flag set.
• IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT must only be used as a fragment density map attachment in a RenderPass. This layout is valid only for image subresources of images created with the IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT usage flag set.
• VK_IMAGE_LAYOUT_VIDEO_DECODE_DST_KHR must only be used as a decode output picture in a video decode operation. This layout is valid only for image subresources of images created with the VK_IMAGE_USAGE_VIDEO_DECODE_DST_BIT_KHR usage flag set.
• VK_IMAGE_LAYOUT_VIDEO_DECODE_SRC_KHR is reserved for future use.
• VK_IMAGE_LAYOUT_VIDEO_DECODE_DPB_KHR must only be used as an output reconstructed picture or an input reference picture in a video decode operation. This layout is valid only for image subresources of images created with the VK_IMAGE_USAGE_VIDEO_DECODE_DPB_BIT_KHR usage flag set.
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_DST_KHR is reserved for future use.
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_SRC_KHR must only be used as an encode input picture in a video encode operation. This layout is valid only for image subresources of images created with the VK_IMAGE_USAGE_VIDEO_ENCODE_SRC_BIT_KHR usage flag set.
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_DPB_KHR must only be used as an output reconstructed picture or an input reference picture in a video encode operation. This layout is valid only for image subresources of images created with the VK_IMAGE_USAGE_VIDEO_ENCODE_DPB_BIT_KHR usage flag set.
• IMAGE_LAYOUT_ATTACHMENT_FEEDBACK_LOOP_OPTIMAL_EXT must only be used as either a color attachment or depth/stencil attachment and/or read-only access in a shader as a sampled image, combined image/sampler, or input attachment. This layout is valid only for image subresources of images created with the IMAGE_USAGE_ATTACHMENT_FEEDBACK_LOOP_BIT_EXT usage flag set, and either the IMAGE_USAGE_COLOR_ATTACHMENT_BIT or IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT usage flags set, and either the IMAGE_USAGE_INPUT_ATTACHMENT_BIT or IMAGE_USAGE_SAMPLED_BIT usage flags set
• IMAGE_LAYOUT_RENDERING_LOCAL_READ must only be used as either a storage image, or a color or depth/stencil attachment and an input attachment. This layout is valid only for image subresources of images created with either the IMAGE_USAGE_STORAGE_BIT usage flag set, or both the IMAGE_USAGE_INPUT_ATTACHMENT_BIT and either of the IMAGE_USAGE_COLOR_ATTACHMENT_BIT or IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT usage flags set.
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_QUANTIZATION_MAP_KHR must only be used as a quantization map in a video encode operation. This layout is valid only for image subresources of images created with the VK_IMAGE_USAGE_VIDEO_ENCODE_QUANTIZATION_DELTA_MAP_BIT_KHR or VK_IMAGE_USAGE_VIDEO_ENCODE_EMPHASIS_MAP_BIT_KHR usage flags set.
• IMAGE_LAYOUT_TENSOR_ALIASING_ARM specifies the layout that an image created with IMAGE_TILING_OPTIMAL must be in, if the unifiedImageLayouts feature is disabled, or may be in if it is enabled, for it and a tensor bound to the same aliased range of memory to consistently interpret the data in memory. See https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#resources-memory-aliasing for a complete set of rules for tensor/image aliasing. This layout is valid only for image subresources of images created with the IMAGE_USAGE_TENSOR_ALIASING_BIT_ARM usage flag set.

The layout of each image subresource is not a state of the image subresource itself, but is rather a property of how the data in memory is organized, and thus for each mechanism of accessing an image in the API the application must specify a parameter or structure member that indicates which image layout the image subresource(s) are considered to be in when the image will be accessed. For transfer commands, this is a parameter to the command (see https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#clears and https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#copies). For use as a framebuffer attachment, this is a member in the substructures of the RenderPassCreateInfo (see Render Pass). For use in a descriptor set, this is a member in the DescriptorImageInfo structure (see https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#descriptorsets-updates).

If the unifiedImageLayouts feature is enabled, the IMAGE_LAYOUT_GENERAL image layout may be used in place of the other layouts where allowed with no loss of performance.

IMAGE_LAYOUT_GENERAL can be a useful catch-all image layout, but there are situations where a dedicated image layout must be used instead. Some examples include:

• IMAGE_LAYOUT_PRESENT_SRC_KHR
• IMAGE_LAYOUT_SHARED_PRESENT_KHR
• VK_IMAGE_LAYOUT_VIDEO_DECODE_SRC_KHR, VK_IMAGE_LAYOUT_VIDEO_DECODE_DST_KHR, and VK_IMAGE_LAYOUT_VIDEO_DECODE_DPB_KHR without the unifiedImageLayoutsVideo feature
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_SRC_KHR, VK_IMAGE_LAYOUT_VIDEO_ENCODE_DST_KHR, and VK_IMAGE_LAYOUT_VIDEO_ENCODE_DPB_KHR without the unifiedImageLayoutsVideo feature
• VK_IMAGE_LAYOUT_VIDEO_ENCODE_QUANTIZATION_MAP_KHR without the unifiedImageLayoutsVideo feature

While IMAGE_LAYOUT_GENERAL suggests that all types of device access is possible, it does not mean that all patterns of memory accesses are safe in all situations. Common Render Pass Data Races outlines some situations where data races are unavoidable. For example, when a subresource is used as both an attachment and a sampled image (i.e., not an input attachment), enabling feedback loop adds extra guarantees which IMAGE_LAYOUT_GENERAL alone does not.

See Also

VK_VERSION_1_0, AttachmentDescription, AttachmentDescription2, AttachmentDescriptionStencilLayout, AttachmentReference, AttachmentReference2, AttachmentReferenceStencilLayout, BlitImageInfo2, CopyBufferToImageInfo2, CopyImageInfo2, CopyImageToBufferInfo2, PromotedStreamingTransfers.CopyImageToImageInfo', PromotedStreamingTransfers.CopyImageToMemoryInfo', CopyMemoryToImageIndirectInfoKHR, PromotedStreamingTransfers.CopyMemoryToImageInfo', DescriptorImageInfo, PromotedStreamingTransfers.HostImageLayoutTransitionInfo', ImageCreateInfo, ImageDescriptorInfoEXT, ImageMemoryBarrier, ImageMemoryBarrier2, PromotedStreamingTransfers.PhysicalDeviceHostImageCopyProperties', PhysicalDeviceVulkan14Properties, RenderingAttachmentInfo, RenderingFragmentDensityMapAttachmentInfoEXT, RenderingFragmentShadingRateAttachmentInfoKHR, ResolveImageInfo2, bindOpticalFlowSessionImageNV, cmdBindInvocationMaskHUAWEI, cmdBindShadingRateImageNV, cmdBlitImage, cmdClearColorImage, cmdClearDepthStencilImage, cmdCopyBufferToImage, cmdCopyImage, cmdCopyImageToBuffer, cmdCopyMemoryToImageIndirectNV, cmdResolveImage