// Copyright (c) 2015-2016 The Khronos Group Inc. // Copyright notice at https://www.khronos.org/registry/speccopyright.html [[copies]] = Copy Commands An application can: copy buffer and image data using several methods depending on the type of data transfer. Data can: be copied between buffer objects with fname:vkCmdCopyBuffer and a portion of an image can: be copied to another image with fname:vkCmdCopyImage. Image data can: also be copied to and from buffer memory using fname:vkCmdCopyImageToBuffer and fname:vkCmdCopyBufferToImage. Image data can: be blitted (with or without scaling and filtering) with fname:vkCmdBlitImage. Multisampled images can: be resolved to a non-multisampled image with fname:vkCmdResolveImage. == Common Operation Some rules for valid operation are common to all copy commands: * Copy commands must: be recorded outside of a render pass instance. * For non-sparse resources, the union of the source regions in a given buffer or image must: not overlap the union of the destination regions in the same buffer or image. * For sparse resources, the set of bytes used by all the source regions must: not intersect the set of bytes used by all the destination regions. * Copy regions must: be non-empty. * Regions must: not extend outside the bounds of the buffer or image level, except that regions of compressed images can: extend as far as the dimension of the image level rounded up to a complete block. * Source image subresources must: be in either the ename:VK_IMAGE_LAYOUT_GENERAL or ename:VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL layout. Destination image subresources must: be in either the ename:VK_IMAGE_LAYOUT_GENERAL or ename:VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL layout. As a consequence, if an image subresource is used as both source and destination of a copy, it must: be in the ename:VK_IMAGE_LAYOUT_GENERAL layout. * Source images must: have been created with the ename:VK_IMAGE_USAGE_TRANSFER_SRC_BIT usage bit enabled and destination images must: have been created with the ename:VK_IMAGE_USAGE_TRANSFER_DST_BIT usage bit enabled. * Source buffers must: have been created with the ename:VK_BUFFER_USAGE_TRANSFER_SRC_BIT usage bit enabled and destination buffers must: have been created with the ename:VK_BUFFER_USAGE_TRANSFER_DST_BIT usage bit enabled. All copy commands are treated as ``transfer'' operations for the purposes of synchronization barriers. [[copies-buffers]] == Copying Data Between Buffers To copy data between buffer objects, call: include::../protos/vkCmdCopyBuffer.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcBuffer is the source buffer. * pname:dstBuffer is the destination buffer. * pname:regionCount is the number of regions to copy. * pname:pRegions is a pointer to an array of slink:VkBufferCopy structures specifying the regions to copy. Each region in pname:pRegions is copied from the source buffer to the same region of the destination buffer. pname:srcBuffer and pname:dstBuffer can: be the same buffer or alias the same memory, but the result is undefined if the copy regions overlap in memory. include::../validity/protos/vkCmdCopyBuffer.txt[] Each element of pname:pRegions is a structure defined as: include::../structs/VkBufferCopy.txt[] * pname:srcOffset is the starting offset in bytes from the start of pname:srcBuffer. * pname:dstOffset is the starting offset in bytes from the start of pname:dstBuffer. * pname:size is the number of bytes to copy. include::../validity/structs/VkBufferCopy.txt[] [[copies-images]] == Copying Data Between Images fname:vkCmdCopyImage performs image copies in a similar manner to a host memcpy. It does not perform general-purpose conversions such as scaling, resizing, blending, color-space conversion, or format conversions. Rather, it simply copies raw image data. fname:vkCmdCopyImage can: copy between images with different formats, provided the formats are compatible as defined below. To copy data between image objects, call: include::../protos/vkCmdCopyImage.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcImage is the source image. * pname:srcImageLayout is the current layout of the source image subresource. * pname:dstImage is the destination image. * pname:dstImageLayout is the current layout of the destination image subresource. * pname:regionCount is the number of regions to copy. * pname:pRegions is a pointer to an array of slink:VkImageCopy structures specifying the regions to copy. Each region in pname:pRegions is copied from the source image to the same region of the destination image. pname:srcImage and pname:dstImage can: be the same image or alias the same memory. include::../validity/protos/vkCmdCopyImage.txt[] Each element of pname:pRegions is a structure defined as: include::../structs/VkImageCopy.txt[] * pname:srcSubresource and pname:dstSubresource are slink:VkImageSubresourceLayers structures specifying the subresources of the images used for the source and destination image data, respectively. * pname:srcOffset and pname:dstOffset select the initial x, y, and z offsets in texels of the sub-regions of the source and destination image data. * pname:extent is the size in texels of the source image to copy in pname:width, pname:height and pname:depth. 1D images use only pname:x and pname:width. 2D images use pname:x, pname:y, pname:width and pname:height. 3D images use pname:x, pname:y, pname:z, pname:width, pname:height and pname:depth. include::../validity/structs/VkImageCopy.txt[] The sname:VkImageSubresourceLayers structure is defined as: include::../structs/VkImageSubresourceLayers.txt[] * pname:aspectMask is a combination of elink:VkImageAspectFlagBits, selecting the color, depth and/or stencil aspects to be copied. * pname:mipLevel is the mipmap level to copy from. * pname:baseArrayLayer and pname:layerCount are the starting layer and number of layers to copy. include::../validity/structs/VkImageSubresourceLayers.txt[] Copies are done layer by layer starting with pname:baseArrayLayer member of pname:srcSubresource for the source and pname:dstSubresource for the destination. pname:layerCount layers are copied to the destination image. [[copies-images-format-compatibility]] The formats of pname:srcImage and pname:dstImage must: be compatible. Formats are considered compatible if their texel size in bytes is the same between both formats. For example, ename:VK_FORMAT_R8G8B8A8_UNORM is compatible with ename:VK_FORMAT_R32_UINT because because both texels are 4 bytes in size. Depth/stencil formats must: match exactly. fname:vkCmdCopyImage allows copying between size-compatible compressed and uncompressed internal formats. Formats are size-compatible if the texel size of the uncompressed format is equal to the block size in bytes of the compressed format. Such a copy does not perform on-the-fly compression or decompression. When copying from an uncompressed format to a compressed format, each texel of uncompressed data becomes a single block of compressed data. When copying from a compressed format to an uncompressed format, a block of compressed data becomes a single texel of uncompressed data. Thus, for example, it is legal to copy between a 128-bit uncompressed format and a compressed format which uses 8-bit/texel 4x4 blocks, or between a 64-bit uncompressed format and a compressed format which uses 4-bit/texel 4x4 blocks. When copying between compressed and uncompressed formats the pname:extent members represent the texel dimensions of the source image and not the destination. When copying from a compressed image to an uncompressed image the image texel dimensions written to the uncompressed image will be source extent divided by the block size. When copying from an uncompressed image to a compressed image the image texel dimensions written to the compressed image will be the source extent multiplied by the block size. In both cases the number of bytes read and the number of bytes written will be identical. Copying to or from block-compressed images is typically done in multiples of the block. For this reason the pname:extent must: be a multiple of the block dimension. There is one exception to this rule which is required: to handle compressed images created with dimensions that are not a multiple of the block dimensions. If the pname:srcImage is compressed and if pname:extent.width is not a multiple of the block width then (pname:extent.width + pname:srcOffset.x) must: equal the subresource width, if pname:extent.height is not a multiple of the block height then (pname:extent.height + pname:srcOffset.y) must: equal the subresource height and if pname:extent.depth is not a multiple of the block depth then (pname:extent.depth + pname:srcOffset.z) must: equal the subresource depth. Similarily if the pname:dstImage is compressed and if pname:extent.width is not a multiple of the block width then (pname:extent.width + pname:dstOffset.x) must: equal the subresource width, if pname:extent.height is not a multiple of the block height then (pname:extent.height + pname:dstOffset.y) must: equal the subresource height and if pname:extent.depth is not a multiple of the block depth then (pname:extent.depth + pname:dstOffset.z) must: equal the subresource depth. This allows the last block of the image in each non-multiple dimension to be included as a source or target of the copy. fname:vkCmdCopyImage can: be used to copy image data between multisample images, but both images must: have the same number of samples. [[copies-buffers-images]] == Copying Data Between Buffers and Images To copy data from a buffer object to an image object, call: include::../protos/vkCmdCopyBufferToImage.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcBuffer is the source buffer. * pname:dstImage is the destination image. * pname:dstImageLayout is the layout of the destination image subresources for the copy. * pname:regionCount is the number of regions to copy. * pname:pRegions is a pointer to an array of slink:VkBufferImageCopy structures specifying the regions to copy. Each region in pname:pRegions is copied from the specified region of the source buffer to the specified region of the destination image. include::../validity/protos/vkCmdCopyBufferToImage.txt[] To copy data from an image object to a buffer object, call: include::../protos/vkCmdCopyImageToBuffer.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcImage is the source image. * pname:srcImageLayout is the layout of the source image subresources for the copy. * pname:dstBuffer is the destination buffer. * pname:regionCount is the number of regions to copy. * pname:pRegions is a pointer to an array of slink:VkBufferImageCopy structures specifying the regions to copy. Each region in pname:pRegions is copied from the specified region of the source image to the specified region of the destination buffer. include::../validity/protos/vkCmdCopyImageToBuffer.txt[] For both flink:vkCmdCopyBufferToImage and flink:vkCmdCopyImageToBuffer, each element of pname:pRegions is a structure defined as: include::../structs/VkBufferImageCopy.txt[] * pname:bufferOffset is the offset in bytes from the start of the buffer object where the image data is copied from or to. * pname:bufferRowLength and pname:bufferImageHeight specify the data in buffer memory as a subregion of a larger two- or three-dimensional image, and control the addressing calculations of data in buffer memory. If either of these values is zero, that aspect of the buffer memory is considered to be tightly packed according to the pname:imageExtent. * pname:imageSubresource is an slink:VkImageSubresourceLayers used to specify the specific subresources of the image used for the source or destination image data. * pname:imageOffset selects the initial x, y, z offsets in texels of the sub-region of the source or destination image data. * pname:imageExtent is the size in texels of the image to copy in pname:width, pname:height and pname:depth. 1D images use only pname:x and pname:width. 2D images use pname:x, pname:y, pname:width and pname:height. 3D images use pname:x, pname:y, pname:z, pname:width, pname:height and pname:depth. When copying to or from a depth or stencil aspect, the data in buffer memory uses a layout that is a (mostly) tightly packed representation of the depth or stencil data. Specifically: * data copied to or from the stencil aspect of any depth/stencil format is tightly packed with one ename:VK_FORMAT_S8_UINT value per texel. * data copied to or from the depth aspect of a ename:VK_FORMAT_D16_UNORM or ename:VK_FORMAT_D16_UNORM_S8_UINT format is tightly packed with one ename:VK_FORMAT_D16_UNORM value per texel. * data copied to or from the depth aspect of a ename:VK_FORMAT_D32_SFLOAT or ename:VK_FORMAT_D32_SFLOAT_S8_UINT format is tightly packed with one ename:VK_FORMAT_D32_SFLOAT value per texel. * data copied to or from the depth aspect of a ename:VK_FORMAT_X8_D24_UNORM_PACK32 or ename:VK_FORMAT_D24_UNORM_S8_UINT format is packed with one 32-bit word per texel with the D24 value in the LSBs of the word, and undefined values in the eight MSBs. [NOTE] .Note ==== To copy both the depth and stencil aspects of a depth/stencil format, two entries in pname:pRegions can: be used, where one specifies the depth aspect in pname:imageSubresource, and the other specifies the stencil aspect. ==== Because depth or stencil aspect buffer to image copies may: require format conversions on some implementations, they are not supported on queues that do not support graphics. Copies are done layer by layer starting with image layer pname:baseArrayLayer member of pname:imageSubresource. pname:layerCount layers are copied from the source image or to the destination image. include::../validity/structs/VkBufferImageCopy.txt[] Pseudocode for image/buffer addressing is: [source,c] --------------------------------------------------- rowLength = region->bufferRowLength; if (rowLength == 0) rowLength = region->imageExtent.width; imageHeight = region->bufferImageHeight; if (imageHeight == 0) imageHeight = region->imageExtent.height; texelSize = ; address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * texelSize; where x,y,z range from (0,0,0) to region->imageExtent.{width,height,depth}. --------------------------------------------------- Note that pname:imageOffset does not affect addressing calculations for buffer memory. Instead, pname:bufferOffset can: be used to select the starting address in buffer memory. For block-compression formats, all parameters are still specified in texels rather than blocks, but the addressing math operates on whole blocks. Pseudocode for compressed copy addressing is: [source,c] --------------------------------------------------- rowLength = region->bufferRowLength; if (rowLength == 0) rowLength = region->imageExtent.width; imageHeight = region->bufferImageHeight; if (imageHeight == 0) imageHeight = region->imageExtent.height; blockSizeInBytes = ; rowLength /= blockWidth; imageHeight /= blockHeight; address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * blockSizeInBytes; where x,y,z range from (0,0,0) to region->imageExtent.{width/blockWidth,height/blockHeight,depth/blockDepth}. --------------------------------------------------- Copying to or from block-compressed images is typically done in multiples of the block. For this reason the pname:imageExtent must: be a multiple of the block dimension. There is one exception to this rule which is required: to handle compressed images created with dimensions that are not a multiple of the block dimensions. If pname:imageExtent.width is not a multiple of the block width then (pname:imageExtent.width + pname:imageOffset.x) must: equal the subresource width, if pname:imageExtent.height is not a multiple of the block height then (pname:imageExtent.height + pname:imageOffset.y) must: equal the subresource height and if pname:imageExtent.depth is not a multiple of the block depth then (pname:imageExtent.depth + pname:imageOffset.z) must: equal the subresource depth. This allows the last block of the image in each non-multiple dimension to be included as a source or target of the copy. [[copies-imagescaling]] == Image Copies with Scaling To copy regions of a source image into a destination image, potentially performing format conversion, arbitrary scaling, and filtering, call: include::../protos/vkCmdBlitImage.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcImage is the source image. * pname:srcImageLayout is the layout of the source image subresources for the blit. * pname:dstImage is the destination image. * pname:dstImageLayout is the layout of the destination image subresources for the blit. * pname:regionCount is the number of regions to blit. * pname:pRegions is a pointer to an array of slink:VkImageBlit structures specifying the regions to blit. * pname:filter is a elink:VkFilter specifying the filter to apply if the blits require scaling. include::../validity/protos/vkCmdBlitImage.txt[] fname:vkCmdBlitImage mustnot: be used for multisampled source or destination images. Use flink:vkCmdResolveImage for this purpose. Each element of pname:pRegions is a structure defined as: include::../structs/VkImageBlit.txt[] For each element of the pname:pRegions array, a blit operation is performed between the region of pname:srcSubresource of pname:srcImage (bounded by pname:srcOffsets[0] and pname:srcOffsets[1]) and a region of pname:dstSubresource of pname:dstImage (bounded by pname:dstOffsets[0] and pname:dstOffsets[1]). include::../validity/structs/VkImageBlit.txt[] If sizes of source and destination extents do not match, scaling is performed by applying the filtering mode specified by pname:filter parameter. ename:VK_FILTER_LINEAR uses bilinear interpolation, and ename:VK_FILTER_NEAREST uses point sampling. When using ename:VK_FILTER_LINEAR, magnifying blits may: generate texel coordinates outside of the source region. If those coordinates are outside the bounds of the image level, the coordinates are clamped as in ename:VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE address mode. However, if the coordinates are outside the source region but inside the image level, the implementation may: clamp coordinates to the source region. If source and destination extents are identical, no filtering is performed. Pixels in the axis-aligned region bounded by srcOffsets[0] and srcOffsets[1] will be copied to the destination region bound by dstOffsets[0] and dstOffsets[1]. In the case where dstOffsets[0].x > dstOffsets[1].x the copied pixels are reversed in that direction. Likewise for y and z. Blits are done layer by layer starting with the pname:baseArrayLayer member of pname:srcSubresource for the source and pname:dstSubresource for the destination. pname:layerCount layers are blitted to the destination image. 3D textures are blitted slice by slice. Slices in the source region bounded by pname:srcOffsets[0].z and pname:srcOffsets[1].z are copied to slices in the destination region bounded by pname:dstOffsets[0].z and pname:dstOffsets[1].z. For each destination slice, a source z coordinate is linearly interpolated between pname:srcOffsets[0].z and pname:srcOffsets[1].z. If the pname:filter parameter is ename:VK_FILTER_LINEAR then the value sampled from the source image is taken by doing linear filtering using the interpolated z coordinate. If pname:filter parameter is ename:VK_FILTER_NEAREST then value sampled from the source image is taken from the single nearest slice (with undefined rounding mode). If fname:vkCmdBlitImage is used on images of different formats, the following conversion rules apply: * Integer formats can: only be converted to other integer formats with the same signedness. * No format conversion is supported between depth/stencil images - the formats must: match. * Format conversions on unorm, snorm, unscaled and packed float formats of the copied aspect of the image are performed by first converting the pixels to float values. * In case of sRGB source format, values are converted to linear color space prior to filtering. * After filtering, the float values are first clamped and then cast to the destination image format. In case of sRGB destination format, values are converted to sRGB color space before writing the pixel to the image. Signed and unsigned integers are converted by first clamping to the representable range of the destination format, then casting the value. [[copies-resolve]] == Resolving Multisample Images To resolve a multisample image to a non-multisample image, call: include::../protos/vkCmdResolveImage.txt[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:srcImage is the source image. * pname:srcImageLayout is the layout of the source image subresources for the resolve. * pname:dstImage is the destination image. * pname:dstImageLayout is the layout of the destination image subresources for the resolve. * pname:regionCount is the number of regions to resolve. * pname:pRegions is a pointer to an array of slink:VkImageResolve structures specifying the regions to resolve. include::../validity/protos/vkCmdResolveImage.txt[] Each element of pname:pRegions is a structure defined as: include::../structs/VkImageResolve.txt[] * pname:srcSubresource and pname:dstSubresource are slink:VkImageSubresourceLayers structures specifying the subresources of the images used for the source and destination image data, respectively. Resolve of depth/stencil images is not supported. * pname:srcOffset and pname:dstOffset select the initial x, y, and z offsets in texels of the sub-regions of the source and destination image data. * pname:extent is the size in texels of the source image to resolve in pname:width, pname:height and pname:depth. 1D images use only pname:x and pname:width. 2D images use pname:x, pname:y, pname:width and pname:height. 3D images use pname:x, pname:y, pname:z, pname:width, pname:height and pname:depth. include::../validity/structs/VkImageResolve.txt[] During the resolve the samples corresponding to each pixel location in the source are converted to a single sample before being written to the destination. If the source formats are floating-point or normalized types, the sample values for each pixel are resolved in an implementation-dependent manner. If the source formats are integer types, a single sample's value is selected for each pixel. pname:srcOffset and pname:dstOffset select the initial x, y, and z offsets in texels of the sub-regions of the source and destination image data. pname:extent is the size in texels of the source image to resolve in pname:width, pname:height and pname:depth. 1D images use only pname:x and pname:width. 2D images use pname:x, pname:y, pname:width and pname:height. 3D images use pname:x, pname:y, pname:z, pname:width, pname:height and pname:depth. Resolves are done layer by layer starting with pname:baseArrayLayer member of pname:srcSubresource for the source and pname:dstSubresource for the destination. pname:layerCount layers are resolved to the destination image.