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:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSampler)
To create a sampler object, call:
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 an instance of the
VkSamplerCreateInfo structure specifying the state of the sampler
object.
pAllocator controls host memory allocation as described in the
Memory Allocation chapter.
pSampler points to a VkSampler handle in which the resulting
sampler object is returned.
The VkSamplerCreateInfo structure is defined as:
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 an extension-specific structure.
flags is reserved for future use.
magFilter is the magnification filter to apply to lookups, and is
of type:
typedef enum VkFilter {
VK_FILTER_NEAREST = 0,
VK_FILTER_LINEAR = 1,
} VkFilter;
minFilter is the minification filter to apply to lookups, and is
of type VkFilter.
mipmapMode is the mipmap filter to apply to lookups as described
in the Texel Filtering section, and is of
type:
typedef enum VkSamplerMipmapMode {
VK_SAMPLER_MIPMAP_MODE_NEAREST = 0,
VK_SAMPLER_MIPMAP_MODE_LINEAR = 1,
} VkSamplerMipmapMode;
addressModeU is the addressing mode for outside [0..1] range for U
coordinate.
See VkSamplerAddressMode.
addressModeV is the addressing mode for outside [0..1] range for V
coordinate.
See VkSamplerAddressMode.
addressModeW is the addressing mode for outside [0..1] range for W
coordinate.
See VkSamplerAddressMode.
mipLodBias is the bias to be added to
mipmap LOD 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.
compareEnable is VK_TRUE to enable comparison against a
reference value during lookups, or VK_FALSE otherwise.
compareOp is the comparison function to apply to fetched data
before filtering as described in the Depth Compare Operation section.
See VkCompareOp.
minLod and maxLod are the values used to clamp the computed
level-of-detail value, as described in the
Level-of-Detail Operation
section.
maxLod must be greater than or equal to minLod.
borderColor is the predefined border color to use, as described in
the Texel Replacement section, and is of
type:
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;
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, samplers have the
following requirements:
minFilter and magFilter must be equal.
mipmapMode must be VK_SAMPLER_MIPMAP_MODE_NEAREST.
minLod and maxLod must be zero.
addressModeU and addressModeV must each be either
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE or
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER.
anisotropyEnable must be VK_FALSE.
compareEnable must be VK_FALSE.
When unnormalizedCoordinates is VK_TRUE, images the sampler
is used with in the shader have the following requirements:
viewType must be either VK_IMAGE_VIEW_TYPE_1D or
VK_IMAGE_VIEW_TYPE_2D.
When unnormalizedCoordinates is VK_TRUE, image built-in
functions in the shader that use the sampler have the following
requirements:
| Mapping of OpenGL to Vulkan filter modes | |
|---|---|
There are no Vulkan filter modes that directly correspond to OpenGL
minification filters of Note that using a |
addressModeU, addressModeV, and addressModeW must each
have one of the following values:
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,
VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE = 4,
} VkSamplerAddressMode;
These values control 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.
VK_SAMPLER_ADDRESS_MODE_REPEAT indicates that the repeat wrap mode
will be used.
VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT indicates that the
mirrored repeat wrap mode will be used.
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE indicates that the clamp to
edge wrap mode will be used.
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER indicates that the clamp
to border wrap mode will be used.
VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE indicates that the
mirror clamp to edge wrap mode will be used.
This is only valid if the VK_KHR_mirror_clamp_to_edge extension is
enabled.
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.
If maxSamplerAllocationCount is exceeded, vkCreateSampler will
return VK_ERROR_TOO_MANY_OBJECTS.
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.
To destroy a sampler, call:
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.