12. Samplers

VkSampler objects represent the state of an image sampler which is used by the implementation to read image data and apply filtering and other transformations for the shader.

Samplers are represented by VkSampler handles:

// Provided by VK_VERSION_1_0
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSampler)

To create a sampler object, call:

// Provided by VK_VERSION_1_0
VkResult vkCreateSampler(
    VkDevice                                    device,
    const VkSamplerCreateInfo*                  pCreateInfo,
    const VkAllocationCallbacks*                pAllocator,
    VkSampler*                                  pSampler);
  • device is the logical device that creates the sampler.

  • pCreateInfo is a pointer to a VkSamplerCreateInfo structure specifying the state of the sampler object.

  • pAllocator controls host memory allocation as described in the Memory Allocation chapter.

  • pSampler is a pointer to a VkSampler handle in which the resulting sampler object is returned.

Valid Usage
  • VUID-vkCreateSampler-maxSamplerAllocationCount-04110
    There must be less than VkPhysicalDeviceLimits::maxSamplerAllocationCount VkSampler objects currently created on the device.

Valid Usage (Implicit)
  • VUID-vkCreateSampler-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkCreateSampler-pCreateInfo-parameter
    pCreateInfo must be a valid pointer to a valid VkSamplerCreateInfo structure

  • VUID-vkCreateSampler-pAllocator-parameter
    If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

  • VUID-vkCreateSampler-pSampler-parameter
    pSampler must be a valid pointer to a VkSampler handle

Return Codes
Success
  • VK_SUCCESS

Failure
  • VK_ERROR_OUT_OF_HOST_MEMORY

  • VK_ERROR_OUT_OF_DEVICE_MEMORY

The VkSamplerCreateInfo structure is defined as:

// Provided by VK_VERSION_1_0
typedef struct VkSamplerCreateInfo {
    VkStructureType         sType;
    const void*             pNext;
    VkSamplerCreateFlags    flags;
    VkFilter                magFilter;
    VkFilter                minFilter;
    VkSamplerMipmapMode     mipmapMode;
    VkSamplerAddressMode    addressModeU;
    VkSamplerAddressMode    addressModeV;
    VkSamplerAddressMode    addressModeW;
    float                   mipLodBias;
    VkBool32                anisotropyEnable;
    float                   maxAnisotropy;
    VkBool32                compareEnable;
    VkCompareOp             compareOp;
    float                   minLod;
    float                   maxLod;
    VkBorderColor           borderColor;
    VkBool32                unnormalizedCoordinates;
} VkSamplerCreateInfo;
  • sType is the type of this structure.

  • pNext is NULL or a pointer to a structure extending this structure.

  • flags is a bitmask of VkSamplerCreateFlagBits describing additional parameters of the sampler.

  • magFilter is a VkFilter value specifying the magnification filter to apply to lookups.

  • minFilter is a VkFilter value specifying the minification filter to apply to lookups.

  • mipmapMode is a VkSamplerMipmapMode value specifying the mipmap filter to apply to lookups.

  • addressModeU is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for U coordinate.

  • addressModeV is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for V coordinate.

  • addressModeW is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for W coordinate.

  • mipLodBias is the bias to be added to mipmap LOD (level-of-detail) calculation and bias provided by image sampling functions in SPIR-V, as described in the Level-of-Detail Operation section.

  • anisotropyEnable is VK_TRUE to enable anisotropic filtering, as described in the Texel Anisotropic Filtering section, or VK_FALSE otherwise.

  • maxAnisotropy is the anisotropy value clamp used by the sampler when anisotropyEnable is VK_TRUE. If anisotropyEnable is VK_FALSE, maxAnisotropy is ignored.

  • compareEnable is VK_TRUE to enable comparison against a reference value during lookups, or VK_FALSE otherwise.

    • Note: Some implementations will default to shader state if this member does not match.

  • compareOp is a VkCompareOp value specifying the comparison function to apply to fetched data before filtering as described in the Depth Compare Operation section.

  • minLod and maxLod are the values used to clamp the computed LOD value, as described in the Level-of-Detail Operation section.

  • borderColor is a VkBorderColor value specifying the predefined border color to use.

  • unnormalizedCoordinates controls whether to use unnormalized or normalized texel coordinates to address texels of the image. When set to VK_TRUE, the range of the image coordinates used to lookup the texel is in the range of zero to the image dimensions for x, y and z. When set to VK_FALSE the range of image coordinates is zero to one.

    When unnormalizedCoordinates is VK_TRUE, images the sampler is used with in the shader have the following requirements:

    • The viewType must be either VK_IMAGE_VIEW_TYPE_1D or VK_IMAGE_VIEW_TYPE_2D.

    • The image view must have a single layer and a single mip level.

    When unnormalizedCoordinates is VK_TRUE, image built-in functions in the shader that use the sampler have the following requirements:

    • The functions must not use projection.

    • The functions must not use offsets.

Mapping of OpenGL to Vulkan filter modes

magFilter values of VK_FILTER_NEAREST and VK_FILTER_LINEAR directly correspond to GL_NEAREST and GL_LINEAR magnification filters. minFilter and mipmapMode combine to correspond to the similarly named OpenGL minification filter of GL_minFilter_MIPMAP_mipmapMode (e.g. minFilter of VK_FILTER_LINEAR and mipmapMode of VK_SAMPLER_MIPMAP_MODE_NEAREST correspond to GL_LINEAR_MIPMAP_NEAREST).

There are no Vulkan filter modes that directly correspond to OpenGL minification filters of GL_LINEAR or GL_NEAREST, but they can be emulated using VK_SAMPLER_MIPMAP_MODE_NEAREST, minLod = 0, and maxLod = 0.25, and using minFilter = VK_FILTER_LINEAR or minFilter = VK_FILTER_NEAREST, respectively.

Note that using a maxLod of zero would cause magnification to always be performed, and the magFilter to always be used. This is valid, just not an exact match for OpenGL behavior. Clamping the maximum LOD to 0.25 allows the λ value to be non-zero and minification to be performed, while still always rounding down to the base level. If the minFilter and magFilter are equal, then using a maxLod of zero also works.

The maximum number of sampler objects which can be simultaneously created on a device is implementation-dependent and specified by the maxSamplerAllocationCount member of the VkPhysicalDeviceLimits structure.

Note

For historical reasons, if maxSamplerAllocationCount is exceeded, some implementations may return VK_ERROR_TOO_MANY_OBJECTS. Exceeding this limit will result in undefined behavior, and an application should not rely on the use of the returned error code in order to identify when the limit is reached.

Since VkSampler is a non-dispatchable handle type, implementations may return the same handle for sampler state vectors that are identical. In such cases, all such objects would only count once against the maxSamplerAllocationCount limit.

Valid Usage
  • VUID-VkSamplerCreateInfo-mipLodBias-01069
    The absolute value of mipLodBias must be less than or equal to VkPhysicalDeviceLimits::maxSamplerLodBias

  • VUID-VkSamplerCreateInfo-maxLod-01973
    maxLod must be greater than or equal to minLod

  • VUID-VkSamplerCreateInfo-anisotropyEnable-01070
    If the anisotropic sampling feature is not enabled, anisotropyEnable must be VK_FALSE

  • VUID-VkSamplerCreateInfo-anisotropyEnable-01071
    If anisotropyEnable is VK_TRUE, maxAnisotropy must be between 1.0 and VkPhysicalDeviceLimits::maxSamplerAnisotropy, inclusive

  • VUID-VkSamplerCreateInfo-minFilter-01645
    If sampler Y′CBCR conversion is enabled and the potential format features of the sampler Y′CBCR conversion do not support VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT, minFilter and magFilter must be equal to the sampler Y′CBCR conversion’s chromaFilter

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01072
    If unnormalizedCoordinates is VK_TRUE, minFilter and magFilter must be equal

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01073
    If unnormalizedCoordinates is VK_TRUE, mipmapMode must be VK_SAMPLER_MIPMAP_MODE_NEAREST

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01074
    If unnormalizedCoordinates is VK_TRUE, minLod and maxLod must be zero

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01075
    If unnormalizedCoordinates is VK_TRUE, addressModeU and addressModeV must each be either VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE or VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01076
    If unnormalizedCoordinates is VK_TRUE, anisotropyEnable must be VK_FALSE

  • VUID-VkSamplerCreateInfo-unnormalizedCoordinates-01077
    If unnormalizedCoordinates is VK_TRUE, compareEnable must be VK_FALSE

  • VUID-VkSamplerCreateInfo-addressModeU-01078
    If any of addressModeU, addressModeV or addressModeW are VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER, borderColor must be a valid VkBorderColor value

  • VUID-VkSamplerCreateInfo-addressModeU-01646
    If sampler Y′CBCR conversion is enabled, addressModeU, addressModeV, and addressModeW must be VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE, anisotropyEnable must be VK_FALSE, and unnormalizedCoordinates must be VK_FALSE

  • VUID-VkSamplerCreateInfo-compareEnable-01080
    If compareEnable is VK_TRUE, compareOp must be a valid VkCompareOp value

Valid Usage (Implicit)
  • VUID-VkSamplerCreateInfo-sType-sType
    sType must be VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO

  • VUID-VkSamplerCreateInfo-pNext-pNext
    pNext must be NULL or a pointer to a valid instance of VkSamplerYcbcrConversionInfo

  • VUID-VkSamplerCreateInfo-sType-unique
    The sType value of each struct in the pNext chain must be unique

  • VUID-VkSamplerCreateInfo-flags-zerobitmask
    flags must be 0

  • VUID-VkSamplerCreateInfo-magFilter-parameter
    magFilter must be a valid VkFilter value

  • VUID-VkSamplerCreateInfo-minFilter-parameter
    minFilter must be a valid VkFilter value

  • VUID-VkSamplerCreateInfo-mipmapMode-parameter
    mipmapMode must be a valid VkSamplerMipmapMode value

  • VUID-VkSamplerCreateInfo-addressModeU-parameter
    addressModeU must be a valid VkSamplerAddressMode value

  • VUID-VkSamplerCreateInfo-addressModeV-parameter
    addressModeV must be a valid VkSamplerAddressMode value

  • VUID-VkSamplerCreateInfo-addressModeW-parameter
    addressModeW must be a valid VkSamplerAddressMode value

Bits which can be set in VkSamplerCreateInfo::flags, specifying additional parameters of a sampler, are:

// Provided by VK_VERSION_1_0
typedef enum VkSamplerCreateFlagBits {
} VkSamplerCreateFlagBits;
// Provided by VK_VERSION_1_0
typedef VkFlags VkSamplerCreateFlags;

VkSamplerCreateFlags is a bitmask type for setting a mask of zero or more VkSamplerCreateFlagBits.

Possible values of the VkSamplerCreateInfo::magFilter and minFilter parameters, specifying filters used for texture lookups, are:

// Provided by VK_VERSION_1_0
typedef enum VkFilter {
    VK_FILTER_NEAREST = 0,
    VK_FILTER_LINEAR = 1,
} VkFilter;
  • VK_FILTER_NEAREST specifies nearest filtering.

  • VK_FILTER_LINEAR specifies linear filtering.

These filters are described in detail in Texel Filtering.

Possible values of the VkSamplerCreateInfo::mipmapMode, specifying the mipmap mode used for texture lookups, are:

// Provided by VK_VERSION_1_0
typedef enum VkSamplerMipmapMode {
    VK_SAMPLER_MIPMAP_MODE_NEAREST = 0,
    VK_SAMPLER_MIPMAP_MODE_LINEAR = 1,
} VkSamplerMipmapMode;
  • VK_SAMPLER_MIPMAP_MODE_NEAREST specifies nearest filtering.

  • VK_SAMPLER_MIPMAP_MODE_LINEAR specifies linear filtering.

These modes are described in detail in Texel Filtering.

Possible values of the VkSamplerCreateInfo::addressMode* parameters, specifying the behavior of sampling with coordinates outside the range [0,1] for the respective u, v, or w coordinate as defined in the Wrapping Operation section, are:

// Provided by VK_VERSION_1_0
typedef enum VkSamplerAddressMode {
    VK_SAMPLER_ADDRESS_MODE_REPEAT = 0,
    VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT = 1,
    VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE = 2,
    VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER = 3,
} VkSamplerAddressMode;
  • VK_SAMPLER_ADDRESS_MODE_REPEAT specifies that the repeat wrap mode will be used.

  • VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT specifies that the mirrored repeat wrap mode will be used.

  • VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE specifies that the clamp to edge wrap mode will be used.

  • VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER specifies that the clamp to border wrap mode will be used.

Possible values of VkSamplerCreateInfo::borderColor, specifying the border color used for texture lookups, are:

// Provided by VK_VERSION_1_0
typedef enum VkBorderColor {
    VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK = 0,
    VK_BORDER_COLOR_INT_TRANSPARENT_BLACK = 1,
    VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK = 2,
    VK_BORDER_COLOR_INT_OPAQUE_BLACK = 3,
    VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE = 4,
    VK_BORDER_COLOR_INT_OPAQUE_WHITE = 5,
} VkBorderColor;
  • VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK specifies a transparent, floating-point format, black color.

  • VK_BORDER_COLOR_INT_TRANSPARENT_BLACK specifies a transparent, integer format, black color.

  • VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK specifies an opaque, floating-point format, black color.

  • VK_BORDER_COLOR_INT_OPAQUE_BLACK specifies an opaque, integer format, black color.

  • VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE specifies an opaque, floating-point format, white color.

  • VK_BORDER_COLOR_INT_OPAQUE_WHITE specifies an opaque, integer format, white color.

These colors are described in detail in Texel Replacement.

To destroy a sampler, call:

// Provided by VK_VERSION_1_0
void vkDestroySampler(
    VkDevice                                    device,
    VkSampler                                   sampler,
    const VkAllocationCallbacks*                pAllocator);
  • device is the logical device that destroys the sampler.

  • sampler is the sampler to destroy.

  • pAllocator controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage
  • VUID-vkDestroySampler-sampler-01082
    All submitted commands that refer to sampler must have completed execution

  • VUID-vkDestroySampler-sampler-01083
    If VkAllocationCallbacks were provided when sampler was created, a compatible set of callbacks must be provided here

  • VUID-vkDestroySampler-sampler-01084
    If no VkAllocationCallbacks were provided when sampler was created, pAllocator must be NULL

Valid Usage (Implicit)
  • VUID-vkDestroySampler-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkDestroySampler-sampler-parameter
    If sampler is not VK_NULL_HANDLE, sampler must be a valid VkSampler handle

  • VUID-vkDestroySampler-pAllocator-parameter
    If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

  • VUID-vkDestroySampler-sampler-parent
    If sampler is a valid handle, it must have been created, allocated, or retrieved from device

Host Synchronization
  • Host access to sampler must be externally synchronized

12.1. Sampler Y′CBCR conversion

To create a sampler with Y′CBCR conversion enabled, add a VkSamplerYcbcrConversionInfo structure to the pNext chain of the VkSamplerCreateInfo structure. To create a sampler Y′CBCR conversion, the samplerYcbcrConversion feature must be enabled. Conversion must be fixed at pipeline creation time, through use of a combined image sampler with an immutable sampler in VkDescriptorSetLayoutBinding.

A VkSamplerYcbcrConversionInfo must be provided for samplers to be used with image views that access VK_IMAGE_ASPECT_COLOR_BIT if the format appears in Formats requiring sampler Y′CBCR conversion for VK_IMAGE_ASPECT_COLOR_BIT image views .

The VkSamplerYcbcrConversionInfo structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkSamplerYcbcrConversionInfo {
    VkStructureType             sType;
    const void*                 pNext;
    VkSamplerYcbcrConversion    conversion;
} VkSamplerYcbcrConversionInfo;
Valid Usage (Implicit)
  • VUID-VkSamplerYcbcrConversionInfo-sType-sType
    sType must be VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO

  • VUID-VkSamplerYcbcrConversionInfo-conversion-parameter
    conversion must be a valid VkSamplerYcbcrConversion handle

A sampler Y′CBCR conversion is an opaque representation of a device-specific sampler Y′CBCR conversion description, represented as a VkSamplerYcbcrConversion handle:

// Provided by VK_VERSION_1_1
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSamplerYcbcrConversion)

To create a VkSamplerYcbcrConversion, call:

// Provided by VK_VERSION_1_1
VkResult vkCreateSamplerYcbcrConversion(
    VkDevice                                    device,
    const VkSamplerYcbcrConversionCreateInfo*   pCreateInfo,
    const VkAllocationCallbacks*                pAllocator,
    VkSamplerYcbcrConversion*                   pYcbcrConversion);
  • device is the logical device that creates the sampler Y′CBCR conversion.

  • pCreateInfo is a pointer to a VkSamplerYcbcrConversionCreateInfo structure specifying the requested sampler Y′CBCR conversion.

  • pAllocator controls host memory allocation as described in the Memory Allocation chapter.

  • pYcbcrConversion is a pointer to a VkSamplerYcbcrConversion handle in which the resulting sampler Y′CBCR conversion is returned.

The interpretation of the configured sampler Y′CBCR conversion is described in more detail in the description of sampler Y′CBCR conversion in the Image Operations chapter.

Valid Usage
Valid Usage (Implicit)
  • VUID-vkCreateSamplerYcbcrConversion-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkCreateSamplerYcbcrConversion-pCreateInfo-parameter
    pCreateInfo must be a valid pointer to a valid VkSamplerYcbcrConversionCreateInfo structure

  • VUID-vkCreateSamplerYcbcrConversion-pAllocator-parameter
    If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

  • VUID-vkCreateSamplerYcbcrConversion-pYcbcrConversion-parameter
    pYcbcrConversion must be a valid pointer to a VkSamplerYcbcrConversion handle

Return Codes
Success
  • VK_SUCCESS

Failure
  • VK_ERROR_OUT_OF_HOST_MEMORY

  • VK_ERROR_OUT_OF_DEVICE_MEMORY

The VkSamplerYcbcrConversionCreateInfo structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkSamplerYcbcrConversionCreateInfo {
    VkStructureType                  sType;
    const void*                      pNext;
    VkFormat                         format;
    VkSamplerYcbcrModelConversion    ycbcrModel;
    VkSamplerYcbcrRange              ycbcrRange;
    VkComponentMapping               components;
    VkChromaLocation                 xChromaOffset;
    VkChromaLocation                 yChromaOffset;
    VkFilter                         chromaFilter;
    VkBool32                         forceExplicitReconstruction;
} VkSamplerYcbcrConversionCreateInfo;
  • sType is the type of this structure.

  • pNext is NULL or a pointer to a structure extending this structure.

  • format is the format of the image from which color information will be retrieved.

  • ycbcrModel describes the color matrix for conversion between color models.

  • ycbcrRange describes whether the encoded values have headroom and foot room, or whether the encoding uses the full numerical range.

  • components applies a swizzle based on VkComponentSwizzle enums prior to range expansion and color model conversion.

  • xChromaOffset describes the sample location associated with downsampled chroma channels in the x dimension. xChromaOffset has no effect for formats in which chroma channels are not downsampled horizontally.

  • yChromaOffset describes the sample location associated with downsampled chroma channels in the y dimension. yChromaOffset has no effect for formats in which the chroma channels are not downsampled vertically.

  • chromaFilter is the filter for chroma reconstruction.

  • forceExplicitReconstruction can be used to ensure that reconstruction is done explicitly, if supported.

Note

Setting forceExplicitReconstruction to VK_TRUE may have a performance penalty on implementations where explicit reconstruction is not the default mode of operation.

If format supports VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT the forceExplicitReconstruction value behaves as if it was set to VK_TRUE.

Sampler Y′CBCR conversion objects do not support external format conversion without additional extensions defining external formats.

Valid Usage
  • VUID-VkSamplerYcbcrConversionCreateInfo-format-04060
    format must represent unsigned normalized values (i.e. the format must be a UNORM format)

  • VUID-VkSamplerYcbcrConversionCreateInfo-format-01650
    The potential format features of the sampler Y′CBCR conversion must support VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT or VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT

  • VUID-VkSamplerYcbcrConversionCreateInfo-xChromaOffset-01651
    If the potential format features of the sampler Y′CBCR conversion do not support VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT, xChromaOffset and yChromaOffset must not be VK_CHROMA_LOCATION_COSITED_EVEN if the corresponding channels are downsampled

  • VUID-VkSamplerYcbcrConversionCreateInfo-xChromaOffset-01652
    If the potential format features of the sampler Y′CBCR conversion do not support VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT, xChromaOffset and yChromaOffset must not be VK_CHROMA_LOCATION_MIDPOINT if the corresponding channels are downsampled

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-02581
    If the format has a _422 or _420 suffix, then components.g must be the identity swizzle

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-02582
    If the format has a _422 or _420 suffix, then components.a must be the identity swizzle, VK_COMPONENT_SWIZZLE_ONE, or VK_COMPONENT_SWIZZLE_ZERO

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-02583
    If the format has a _422 or _420 suffix, then components.r must be the identity swizzle or VK_COMPONENT_SWIZZLE_B

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-02584
    If the format has a _422 or _420 suffix, then components.b must be the identity swizzle or VK_COMPONENT_SWIZZLE_R

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-02585
    If the format has a _422 or _420 suffix, and if either components.r or components.b is the identity swizzle, both values must be the identity swizzle

  • VUID-VkSamplerYcbcrConversionCreateInfo-ycbcrModel-01655
    If ycbcrModel is not VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY, then components.r, components.g, and components.b must correspond to channels of the format; that is, components.r, components.g, and components.b must not be VK_COMPONENT_SWIZZLE_ZERO or VK_COMPONENT_SWIZZLE_ONE, and must not correspond to a channel which contains zero or one as a consequence of conversion to RGBA

  • VUID-VkSamplerYcbcrConversionCreateInfo-ycbcrRange-02748
    If ycbcrRange is VK_SAMPLER_YCBCR_RANGE_ITU_NARROW then the R, G and B channels obtained by applying the component swizzle to format must each have a bit-depth greater than or equal to 8

  • VUID-VkSamplerYcbcrConversionCreateInfo-forceExplicitReconstruction-01656
    If the potential format features of the sampler Y′CBCR conversion do not support VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT forceExplicitReconstruction must be VK_FALSE

  • VUID-VkSamplerYcbcrConversionCreateInfo-chromaFilter-01657
    If the potential format features of the sampler Y′CBCR conversion do not support VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT, chromaFilter must not be VK_FILTER_LINEAR

Valid Usage (Implicit)
  • VUID-VkSamplerYcbcrConversionCreateInfo-sType-sType
    sType must be VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO

  • VUID-VkSamplerYcbcrConversionCreateInfo-pNext-pNext
    pNext must be NULL

  • VUID-VkSamplerYcbcrConversionCreateInfo-format-parameter
    format must be a valid VkFormat value

  • VUID-VkSamplerYcbcrConversionCreateInfo-ycbcrModel-parameter
    ycbcrModel must be a valid VkSamplerYcbcrModelConversion value

  • VUID-VkSamplerYcbcrConversionCreateInfo-ycbcrRange-parameter
    ycbcrRange must be a valid VkSamplerYcbcrRange value

  • VUID-VkSamplerYcbcrConversionCreateInfo-components-parameter
    components must be a valid VkComponentMapping structure

  • VUID-VkSamplerYcbcrConversionCreateInfo-xChromaOffset-parameter
    xChromaOffset must be a valid VkChromaLocation value

  • VUID-VkSamplerYcbcrConversionCreateInfo-yChromaOffset-parameter
    yChromaOffset must be a valid VkChromaLocation value

  • VUID-VkSamplerYcbcrConversionCreateInfo-chromaFilter-parameter
    chromaFilter must be a valid VkFilter value

If chromaFilter is VK_FILTER_NEAREST, chroma samples are reconstructed to luma channel resolution using nearest-neighbour sampling. Otherwise, chroma samples are reconstructed using interpolation. More details can be found in the description of sampler Y′CBCR conversion in the Image Operations chapter.

VkSamplerYcbcrModelConversion defines the conversion from the source color model to the shader color model. Possible values are:

// Provided by VK_VERSION_1_1
typedef enum VkSamplerYcbcrModelConversion {
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY = 0,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY = 1,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 = 2,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 = 3,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 = 4,
} VkSamplerYcbcrModelConversion;
  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY specifies that the input values to the conversion are unmodified.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY specifies no model conversion but the inputs are range expanded as for Y′CBCR.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.709 and described in the “BT.709 Y’CBCR conversion” section of the Khronos Data Format Specification.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.601 and described in the “BT.601 Y’CBCR conversion” section of the Khronos Data Format Specification.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.2020 and described in the “BT.2020 Y’CBCR conversion” section of the Khronos Data Format Specification.

In the VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_* color models, for the input to the sampler Y′CBCR range expansion and model conversion:

  • the Y (Y′ luma) channel corresponds to the G channel of an RGB image.

  • the CB (CB or “U” blue color difference) channel corresponds to the B channel of an RGB image.

  • the CR (CR or “V” red color difference) channel corresponds to the R channel of an RGB image.

  • the alpha channel, if present, is not modified by color model conversion.

These rules reflect the mapping of channels after the channel swizzle operation (controlled by VkSamplerYcbcrConversionCreateInfo::components).

Note

For example, an “YUVA” 32-bit format comprising four 8-bit channels can be implemented as VK_FORMAT_R8G8B8A8_UNORM with a component mapping:

  • components.a = VK_COMPONENT_SWIZZLE_IDENTITY

  • components.r = VK_COMPONENT_SWIZZLE_B

  • components.g = VK_COMPONENT_SWIZZLE_R

  • components.b = VK_COMPONENT_SWIZZLE_G

The VkSamplerYcbcrRange enum describes whether color channels are encoded using the full range of numerical values or whether values are reserved for headroom and foot room. VkSamplerYcbcrRange is defined as:

// Provided by VK_VERSION_1_1
typedef enum VkSamplerYcbcrRange {
    VK_SAMPLER_YCBCR_RANGE_ITU_FULL = 0,
    VK_SAMPLER_YCBCR_RANGE_ITU_NARROW = 1,
} VkSamplerYcbcrRange;
  • VK_SAMPLER_YCBCR_RANGE_ITU_FULL specifies that the full range of the encoded values are valid and interpreted according to the ITU “full range” quantization rules.

  • VK_SAMPLER_YCBCR_RANGE_ITU_NARROW specifies that headroom and foot room are reserved in the numerical range of encoded values, and the remaining values are expanded according to the ITU “narrow range” quantization rules.

The formulae for these conversions is described in the Sampler Y′CBCR Range Expansion section of the Image Operations chapter.

No range modification takes place if ycbcrModel is VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY; the ycbcrRange field of VkSamplerYcbcrConversionCreateInfo is ignored in this case.

The VkChromaLocation enum defines the location of downsampled chroma channel samples relative to the luma samples, and is defined as:

// Provided by VK_VERSION_1_1
typedef enum VkChromaLocation {
    VK_CHROMA_LOCATION_COSITED_EVEN = 0,
    VK_CHROMA_LOCATION_MIDPOINT = 1,
} VkChromaLocation;
  • VK_CHROMA_LOCATION_COSITED_EVEN specifies that downsampled chroma samples are aligned with luma samples with even coordinates.

  • VK_CHROMA_LOCATION_MIDPOINT specifies that downsampled chroma samples are located half way between each even luma sample and the nearest higher odd luma sample.

To destroy a sampler Y′CBCR conversion, call:

// Provided by VK_VERSION_1_1
void vkDestroySamplerYcbcrConversion(
    VkDevice                                    device,
    VkSamplerYcbcrConversion                    ycbcrConversion,
    const VkAllocationCallbacks*                pAllocator);
  • device is the logical device that destroys the Y′CBCR conversion.

  • ycbcrConversion is the conversion to destroy.

  • pAllocator controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage (Implicit)
  • VUID-vkDestroySamplerYcbcrConversion-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkDestroySamplerYcbcrConversion-ycbcrConversion-parameter
    If ycbcrConversion is not VK_NULL_HANDLE, ycbcrConversion must be a valid VkSamplerYcbcrConversion handle

  • VUID-vkDestroySamplerYcbcrConversion-pAllocator-parameter
    If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

  • VUID-vkDestroySamplerYcbcrConversion-ycbcrConversion-parent
    If ycbcrConversion is a valid handle, it must have been created, allocated, or retrieved from device

Host Synchronization
  • Host access to ycbcrConversion must be externally synchronized