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ef053e7c82
* Bump API patch number and header version number to 27 for this update.
Github Issues:
* Weaken flink:vkGetPipelineCacheData invariance conditions; previous
conditions were stronger than agreed and can't be guaranteed (public
issue 280).
* Add link to "Vulkan Loader Specification and Architecture Overview"
document to Normative References section (public issue 359).
Internal Issues:
* Be more clear in the <<interfaces-resources-layout-std140, uniform
buffer layout>> section that block offsets can be out of order
(internal issue 396).
* Document that extension authors should add support for their extensions
to the validation layers (internal issue 398).
* Clarify that the valid range of depth clear values should be limited
to the 0..1 range and that copies to depth aspect must also be in this
range (internal issue 412).
* Specify ``a'' vs. ``an'' use in the style guide (internal issue 432).
* Increase the maximum pname:nonCoherentAtomSize value in the
<<features-limits-required,Required Limits>> section from 128 to 256
(internal issue 435).
* Fix vk_platform.h for compiler errors on some Android platforms
(internal issue 441).
* Clarify that slink:VkPhysicalDeviceFeatures::pname:pEnabledFeatures ==
`NULL` disables all features, including the "required" feature
pname:robustBufferAccess (internal issue 479).
Other Issues:
* Expand style guide and make it more self-consistent.
* Use ISO 8601 date format everywhere.
* Emphasise the correct way of using
slink:VkSurfaceCapabilitiesKHR::pname:maxImageCount.
* Added +VK_EXT_validation_flags+ extension for validation flag mechanism.
* Fix an <<credits,author credit>> to include their current employer.
201 lines
9.0 KiB
Plaintext
201 lines
9.0 KiB
Plaintext
// Copyright (c) 2015-2016 The Khronos Group Inc.
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// Copyright notice at https://www.khronos.org/registry/speccopyright.html
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[[samplers]]
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= Samplers
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// refBegin VkSampler Opaque handle to a sampler object
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sname:VkSampler objects represent the state of an image sampler which is
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used by the implementation to read image data and apply filtering and other
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transformations for the shader.
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Samplers are represented by sname:VkSampler handles:
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include::../api/handles/VkSampler.txt[]
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// refEnd VkSampler
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// refBegin vkCreateSampler Create a new sampler object
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To create a sampler object, call:
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include::../api/protos/vkCreateSampler.txt[]
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* pname:device is the logical device that creates the sampler.
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* pname:pCreateInfo is a pointer to an instance of the
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slink:VkSamplerCreateInfo structure specifying the state of the sampler
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object.
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* pname:pAllocator controls host memory allocation as described in the
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<<memory-allocation, Memory Allocation>> chapter.
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* pname:pSampler points to a sname:VkSampler handle in which the resulting
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sampler object is returned.
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include::../validity/protos/vkCreateSampler.txt[]
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// refBegin VkSamplerCreateInfo Structure specifying parameters of a newly created sampler
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The sname:VkSamplerCreateInfo structure is defined as:
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include::../api/structs/VkSamplerCreateInfo.txt[]
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* pname:sType is the type of this structure.
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* pname:pNext is `NULL` or a pointer to an extension-specific structure.
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* pname:flags is reserved for future use.
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* pname:magFilter is the magnification filter to apply to lookups, and
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is of type:
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+
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--
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// refBegin VkFilter Specify filters used for texture lookups
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include::../api/enums/VkFilter.txt[]
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--
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+
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* pname:minFilter is the minification filter to apply to lookups, and is
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of type elink:VkFilter.
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* pname:mipmapMode is the mipmap filter to apply to lookups as described
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in the <<textures-texel-filtering, Texel Filtering>> section, and is of
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type:
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+
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--
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// refBegin VkSamplerMipmapMode Specify mipmap mode used for texture lookups
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include::../api/enums/VkSamplerMipmapMode.txt[]
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--
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+
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* pname:addressModeU is the addressing mode for outside [0..1] range for U
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coordinate. See elink:VkSamplerAddressMode.
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* pname:addressModeV is the addressing mode for outside [0..1] range for V
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coordinate. See elink:VkSamplerAddressMode.
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* pname:addressModeW is the addressing mode for outside [0..1] range for W
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coordinate. See elink:VkSamplerAddressMode.
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* [[samplers-mipLodBias]] pname:mipLodBias is the bias to be added to
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mipmap LOD calculation and bias provided by image sampling functions in
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SPIR-V, as described in the <<textures-level-of-detail-operation,
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Level-of-Detail Operation>> section.
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* [[samplers-maxAnisotropy]] pname:anisotropyEnable is ename:VK_TRUE to
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enable anisotropic filtering, as described in the
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<<textures-texel-anisotropic-filtering, Texel Anisotropic Filtering>>
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section, or ename:VK_FALSE otherwise.
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* pname:maxAnisotropy is the anisotropy value clamp.
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* pname:compareEnable is ename:VK_TRUE to enable comparison against a
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reference value during lookups, or ename:VK_FALSE otherwise.
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** Note: Some implementations will default to shader state if this member
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does not match.
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* pname:compareOp is the comparison function to apply to fetched data
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before filtering as described in the <<textures-depth-compare-operation,
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Depth Compare Operation>> section. See elink:VkCompareOp.
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* pname:minLod and pname:maxLod are the values used to clamp the computed
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level-of-detail value, as described in the
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<<textures-level-of-detail-operation, Level-of-Detail Operation>>
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section. pname:maxLod must: be greater than or equal to pname:minLod.
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* pname:borderColor is the predefined border color to use, as described
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in the <<textures-texel-replacement, Texel Replacement>>
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section, and is of type:
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+
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--
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// refBegin VkBorderColor Specify border color used for texture lookups
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include::../api/enums/VkBorderColor.txt[]
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--
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+
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* [[samplers-unnormalizedCoordinates]] pname:unnormalizedCoordinates
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controls whether to use unnormalized or normalized texel coordinates to
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address texels of the image. When set to ename:VK_TRUE, the range of the
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image coordinates used to lookup the texel is in the range of zero to
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the image dimensions for x, y and z. When set to ename:VK_FALSE the
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range of image coordinates is zero to one. When
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pname:unnormalizedCoordinates is ename:VK_TRUE, samplers have the
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following requirements:
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** pname:minFilter and pname:magFilter must: be equal.
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** pname:mipmapMode must: be ename:VK_SAMPLER_MIPMAP_MODE_NEAREST.
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** pname:minLod and pname:maxLod must: be zero.
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** pname:addressModeU and pname:addressModeV must: each
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be either ename:VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE or
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ename:VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER.
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** pname:anisotropyEnable must: be ename:VK_FALSE.
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** pname:compareEnable must: be ename:VK_FALSE.
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* When pname:unnormalizedCoordinates is ename:VK_TRUE, images the sampler
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is used with in the shader have the following requirements:
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** The pname:viewType must: be either ename:VK_IMAGE_VIEW_TYPE_1D or
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ename:VK_IMAGE_VIEW_TYPE_2D.
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** The image view must: have a single layer and a single mip level.
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* When pname:unnormalizedCoordinates is ename:VK_TRUE, image built-in
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functions in the shader that use the sampler have the following
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requirements:
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** The functions must: not use projection.
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** The functions must: not use offsets.
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[NOTE]
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.Mapping of OpenGL to Vulkan filter modes
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==================
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pname:magFilter values of ename:VK_FILTER_NEAREST and ename:VK_FILTER_LINEAR
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directly correspond to code:GL_NEAREST and code:GL_LINEAR magnification
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filters. pname:minFilter and pname:mipmapMode combine to correspond to the
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similarly named OpenGL minification filter of
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code:GL_minFilter_MIPMAP_mipmapMode (e.g. pname:minFilter of
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ename:VK_FILTER_LINEAR and pname:mipmapMode of
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ename:VK_SAMPLER_MIPMAP_MODE_NEAREST correspond to
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code:GL_LINEAR_MIPMAP_NEAREST).
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There are no Vulkan filter modes that directly correspond to OpenGL
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minification filters of code:GL_LINEAR or code:GL_NEAREST, but they can: be
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emulated using ename:VK_SAMPLER_MIPMAP_MODE_NEAREST, pname:minLod = 0, and
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pname:maxLod = 0.25, and using pname:minFilter = ename:VK_FILTER_LINEAR or
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pname:minFilter = ename:VK_FILTER_NEAREST, respectively.
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Note that using a pname:maxLod of zero would cause
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<<textures-texel-filtering,magnification>> to always be performed, and the
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pname:magFilter to always be used. This is valid, just not an exact match
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for OpenGL behavior. Clamping the maximum LOD to 0.25 allows the
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latexmath:[$\lambda$] value to be non-zero and minification to be performed,
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while still always rounding down to the base level. If the pname:minFilter
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and pname:magFilter are equal, then using a pname:maxLod of zero also works.
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==================
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pname:addressModeU, pname:addressModeV, and pname:addressModeW must: each
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have one of the following values:
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// refBegin VkSamplerAddressMode Specify behavior of sampling with texture coordinates outside an image
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include::../api/enums/VkSamplerAddressMode.txt[]
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These values control the behavior of sampling with coordinates outside the
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range latexmath:[$[0,1\]$] for the respective u, v, or w coordinate as defined in the
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<<textures-wrapping-operation, Wrapping Operation>> section.
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* ename:VK_SAMPLER_ADDRESS_MODE_REPEAT indicates that the repeat wrap mode
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will be used.
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* ename:VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT indicates that the
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mirrored repeat wrap mode will be used.
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* ename:VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE indicates that the clamp to
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edge wrap mode will be used.
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* ename:VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER indicates that the clamp
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to border wrap mode will be used.
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* ename:VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE indicates that
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the mirror clamp to edge wrap mode will be used. This is only valid
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if the +VK_KHR_mirror_clamp_to_edge+ extension is enabled.
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The maximum number of sampler objects which can: be simultaneously created
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on a device is implementation-dependent and specified by the
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<<features-limits-maxSamplerAllocationCount,pname:maxSamplerAllocationCount>>
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member of the sname:VkPhysicalDeviceLimits structure. If
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pname:maxSamplerAllocationCount is exceeded, fname:vkCreateSampler will
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return ename:VK_ERROR_TOO_MANY_OBJECTS.
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Since sname:VkSampler is a non-dispatchable handle type, implementations
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may: return the same handle for sampler state vectors that are identical. In
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such cases, all such objects would only count once against the
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pname:maxSamplerAllocationCount limit.
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include::../validity/structs/VkSamplerCreateInfo.txt[]
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// refBegin vkDestroySampler Destroy a sampler object
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To destroy a sampler, call:
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include::../api/protos/vkDestroySampler.txt[]
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* pname:device is the logical device that destroys the sampler.
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* pname:sampler is the sampler to destroy.
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* pname:pAllocator controls host memory allocation as described in the
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<<memory-allocation, Memory Allocation>> chapter.
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include::../validity/protos/vkDestroySampler.txt[]
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