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685295031d
* Bump API patch number and header version number to 49 for this update.
Github Issues:
* Modify reference page extraction script to make internal links to spec
anchors refer to the core specification instead of being dangling links
(public issue 455).
* Fix GL_KHR_vulkan_glsl typo and add a nor-normative mapping to the newly
published StorageBuffer class (public issue 466).
* Both flink:vkEnumerateInstanceExtensionProperties and
flink:vkEnumerateDeviceExtensionProperties return
ename:VK_ERROR_LAYER_NOT_PRESENT, which covers the error case of an
application providing a layer name that wasn't returned by
ftext:vkEnumerate{Instance|Device}LayerProperties (public issue 487).
* The specification for flink:VkApplicationInfo::apiVersion says that the
driver must return ename:VK_ERROR_INCOMPATIBLE_DRIVER in the case that
pname:apiVersion specifies a non-supported version. That means that the
valid usage should not also state that, and so the VU statement is
removed. The VU had language about "`an effective substitute`" that
would have been lost, and so it was moved to the pname:apiVersion
description (public issue 488).
Internal Issues:
* Modify implicit validity generator script to assign asciidoc anchors to
all valid usage statements it generates, and reflow.py script to insert
Valid Usage ID (VUID) tags into the specification source files for
explicit valid usage statements. This has no semantic effects on the
specification, but will support the validation layer's detection of
valid usage violations and allow it to link into the corresponding part
of the specification (internal issue 583).
* Assign VUID tags to all explicit VU statements and document
the process and tag format in the style guide (internal issue 583).
* Clarify the rules of whether to structure new functionality as instance
extensions, device extensions, or both in the
<<extended-functionality-instance-extensions-and-devices, Instance
Extensions and Device Extensions>> section (internal issue 749).
* Require that SPIR-V run-time arrays are only used with the
code:BufferBlock decoration (internal issue 750).
* Fix implicit and explicit valid usage statements for
slink:VkWriteDescriptorSet::pname:dstSet (internal issue 767)
* Fix SPIR-V code sample for ename:VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER
in the <<descriptorsets-uniformtexelbuffer, Uniform Texel Buffer>>
section (internal issue 770).
* Clarify that disabling depth testing also disables depth writes in the
<<fragops-ds-state, Depth and Stencil Operations>> section (internal
issue 775).
* flink:VkDescriptorImageInfo::pname:imageLayout must match the actual
imageLayout at the time the image is accessed. This was in the spec
text, but needed an associated valid usage statement.
* Note that only 32-bit atomic operations are supported in the
<<spirvenv-module-validation, Validation Rules within a Module>>
section.
* Note that code:UniformConstant variables must not have initializers in
the <<spirvenv-module-validation, Validation Rules within a Module>>
section.
* Add a new elink:VkObjectType enumeration to the core API, promoted from
elink:VkDebugObjectTypeEXT, since it is used for much more than just the
debug_report extension.
New Extensions:
* `VK_KHR_get_surface_capabilities2`
* `VK_KHR_shared_presentable_image`
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// Copyright (c) 2015-2017 The Khronos Group Inc.
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// Copyright notice at https://www.khronos.org/registry/speccopyright.html
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[[framebuffer]]
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= The Framebuffer
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[[framebuffer-blending]]
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== Blending
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Blending combines the incoming _source_ fragment's R, G, B, and A values
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with the _destination_ R, G, B, and A values of each sample stored in the
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framebuffer at the fragment's [eq]#(x~f~,y~f~)# location.
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Blending is performed for each pixel sample, rather than just once for each
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fragment.
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Source and destination values are combined according to the
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<<framebuffer-blendoperations,blend operation>>, quadruplets of source and
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destination weighting factors determined by the <<framebuffer-blendfactors,
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blend factors>>, and a <<framebuffer-blendconstants,blend constant>>, to
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obtain a new set of R, G, B, and A values, as described below.
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Blending is computed and applied separately to each color attachment used by
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the subpass, with separate controls for each attachment.
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Prior to performing the blend operation, signed and unsigned normalized
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fixed-point color components undergo an implied conversion to floating-point
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as specified by <<fundamentals-fixedfpconv,Conversion from Normalized
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Fixed-Point to Floating-Point>>.
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Blending computations are treated as if carried out in floating-point, and
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will be performed with a precision and dynamic range no lower than that used
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to represent destination components.
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Blending applies only to fixed-point and floating-point color attachments.
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If the color attachment has an integer format, blending is not applied.
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The pipeline blend state is included in the
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sname:VkPipelineColorBlendStateCreateInfo structure during graphics pipeline
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creation:
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// refBegin VkPipelineColorBlendStateCreateInfo Structure specifying parameters of a newly created pipeline color blend state
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The sname:VkPipelineColorBlendStateCreateInfo structure is defined as:
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include::../api/structs/VkPipelineColorBlendStateCreateInfo.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:logicOpEnable controls whether to apply <<framebuffer-logicop,
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Logical Operations>>.
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* pname:logicOp selects which logical operation to apply.
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* pname:attachmentCount is the number of
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sname:VkPipelineColorBlendAttachmentState elements in
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pname:pAttachments.
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This value must: equal the pname:colorAttachmentCount for the subpass in
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which this pipeline is used.
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* pname:pAttachments: is a pointer to array of per target attachment
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states.
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* pname:blendConstants is an array of four values used as the R, G, B, and
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A components of the blend constant that are used in blending, depending
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on the <<framebuffer-blendfactors,blend factor>>.
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Each element of the pname:pAttachments array is a
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slink:VkPipelineColorBlendAttachmentState structure specifying per-target
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blending state for each individual color attachment.
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If the <<features-features-independentBlend,independent blending>> feature
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is not enabled on the device, all slink:VkPipelineColorBlendAttachmentState
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elements in the pname:pAttachments array must: be identical.
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.Valid Usage
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****
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* [[VUID-VkPipelineColorBlendStateCreateInfo-pAttachments-00605]] If the <<features-features-independentBlend,independent blending>>
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feature is not enabled, all elements of pname:pAttachments must: be
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identical
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* [[VUID-VkPipelineColorBlendStateCreateInfo-logicOpEnable-00606]] If the <<features-features-logicOp,logic operations>> feature is not
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enabled, pname:logicOpEnable must: be ename:VK_FALSE
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* [[VUID-VkPipelineColorBlendStateCreateInfo-logicOpEnable-00607]] If pname:logicOpEnable is ename:VK_TRUE, pname:logicOp must: be a valid
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elink:VkLogicOp value
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****
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include::../validity/structs/VkPipelineColorBlendStateCreateInfo.txt[]
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// refBegin VkPipelineColorBlendAttachmentState Structure specifying a pipeline color blend attachment state
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The sname:VkPipelineColorBlendAttachmentState structure is defined as:
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include::../api/structs/VkPipelineColorBlendAttachmentState.txt[]
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* pname:blendEnable controls whether blending is enabled for the
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corresponding color attachment.
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If blending is not enabled, the source fragment's color for that
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attachment is passed through unmodified.
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* pname:srcColorBlendFactor selects which blend factor is used to
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determine the source factors [eq]#(S~r~,S~g~,S~b~)#.
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* pname:dstColorBlendFactor selects which blend factor is used to
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determine the destination factors [eq]#(D~r~,D~g~,D~b~)#.
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* pname:colorBlendOp selects which blend operation is used to calculate
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the RGB values to write to the color attachment.
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* pname:srcAlphaBlendFactor selects which blend factor is used to
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determine the source factor [eq]#S~a~#.
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* pname:dstAlphaBlendFactor selects which blend factor is used to
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determine the destination factor [eq]#D~a~#.
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* pname:alphaBlendOp selects which blend operation is use to calculate the
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alpha values to write to the color attachment.
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* pname:colorWriteMask is a bitmask selecting which of the R, G, B, and/or
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A components are enabled for writing, as described in the
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<<framebuffer-color-write-mask,Color Write Mask>> section.
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.Valid Usage
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****
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* [[VUID-VkPipelineColorBlendAttachmentState-srcColorBlendFactor-00608]] If the <<features-features-dualSrcBlend,dual source blending>> feature
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is not enabled, pname:srcColorBlendFactor must: not be
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ename:VK_BLEND_FACTOR_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_SRC1_ALPHA, or
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA
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* [[VUID-VkPipelineColorBlendAttachmentState-dstColorBlendFactor-00609]] If the <<features-features-dualSrcBlend,dual source blending>> feature
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is not enabled, pname:dstColorBlendFactor must: not be
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ename:VK_BLEND_FACTOR_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_SRC1_ALPHA, or
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA
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* [[VUID-VkPipelineColorBlendAttachmentState-srcAlphaBlendFactor-00610]] If the <<features-features-dualSrcBlend,dual source blending>> feature
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is not enabled, pname:srcAlphaBlendFactor must: not be
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ename:VK_BLEND_FACTOR_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_SRC1_ALPHA, or
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA
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* [[VUID-VkPipelineColorBlendAttachmentState-dstAlphaBlendFactor-00611]] If the <<features-features-dualSrcBlend,dual source blending>> feature
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is not enabled, pname:dstAlphaBlendFactor must: not be
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ename:VK_BLEND_FACTOR_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_SRC1_ALPHA, or
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA
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****
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include::../validity/structs/VkPipelineColorBlendAttachmentState.txt[]
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[[framebuffer-blendfactors]]
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=== Blend Factors
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// refBegin VkBlendFactor Framebuffer blending factors
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The source and destination color and alpha blending factors are selected
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from the enum:
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include::../api/enums/VkBlendFactor.txt[]
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The semantics of each enum value is described in the table below:
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.Blend Factors
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[width="100%",options="header",align="center",cols="59%,28%,13%"]
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|====
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|VkBlendFactor | RGB Blend Factors [eq]#(S~r~,S~g~,S~b~)# or [eq]#(D~r~,D~g~,D~b~)# | Alpha Blend Factor ([eq]#S~a~# or [eq]#D~a~#)
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|ename:VK_BLEND_FACTOR_ZERO | [eq]#(0,0,0)# | [eq]#0#
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|ename:VK_BLEND_FACTOR_ONE | [eq]#(1,1,1)# | [eq]#1#
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|ename:VK_BLEND_FACTOR_SRC_COLOR | [eq]#(R~s0~,G~s0~,B~s0~)# | [eq]#A~s0~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR | [eq]#(1-R~s0~,1-G~s0~,1-B~s0~)# | [eq]#1-A~s0~#
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|ename:VK_BLEND_FACTOR_DST_COLOR | [eq]#(R~d~,G~d~,B~d~)# | [eq]#A~d~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR | [eq]#(1-R~d~,1-G~d~,1-B~d~)# | [eq]#1-A~d~#
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|ename:VK_BLEND_FACTOR_SRC_ALPHA | [eq]#(A~s0~,A~s0~,A~s0~)# | [eq]#A~s0~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA | [eq]#(1-A~s0~,1-A~s0~,1-A~s0~)# | [eq]#1-A~s0~#
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|ename:VK_BLEND_FACTOR_DST_ALPHA | [eq]#(A~d~,A~d~,A~d~)# | [eq]#A~d~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA | [eq]#(1-A~d~,1-A~d~,1-A~d~)# | [eq]#1-A~d~#
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|ename:VK_BLEND_FACTOR_CONSTANT_COLOR | [eq]#(R~c~,G~c~,B~c~)# | [eq]#A~c~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR | [eq]#(1-R~c~,1-G~c~,1-B~c~)# | [eq]#1-A~c~#
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|ename:VK_BLEND_FACTOR_CONSTANT_ALPHA | [eq]#(A~c~,A~c~,A~c~)# | [eq]#A~c~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA | [eq]#(1-A~c~,1-A~c~,1-A~c~)# | [eq]#1-A~c~#
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|ename:VK_BLEND_FACTOR_SRC_ALPHA_SATURATE | [eq]#(f,f,f)#; [eq]#f = min(A~s0~,1-A~d~)# | [eq]#1#
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|ename:VK_BLEND_FACTOR_SRC1_COLOR | [eq]#(R~s1~,G~s1~,B~s1~)# | [eq]#A~s1~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR | [eq]#(1-R~s1~,1-G~s1~,1-B~s1~)# | [eq]#1-A~s1~#
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|ename:VK_BLEND_FACTOR_SRC1_ALPHA | [eq]#(A~s1~,A~s1~,A~s1~)# | [eq]#A~s1~#
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|ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA | [eq]#(1-A~s1~,1-A~s1~,1-A~s1~)# | [eq]#1-A~s1~#
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|====
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In this table, the following conventions are used:
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* [eq]#R~s0~,G~s0~,B~s0~# and [eq]#A~s0~# represent the first source color
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R, G, B, and A components, respectively, for the fragment output
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location corresponding to the color attachment being blended.
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* [eq]#R~s1~,G~s1~,B~s1~# and [eq]#A~s1~# represent the second source
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color R, G, B, and A components, respectively, used in dual source
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blending modes, for the fragment output location corresponding to the
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color attachment being blended.
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* [eq]#R~d~,G~d~,B~d~# and [eq]#A~d~# represent the R, G, B, and A
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components of the destination color.
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That is, the color currently in the corresponding color attachment for
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this fragment/sample.
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* [eq]#R~c~,G~c~,B~c~# and [eq]#A~c~# represent the blend constant R, G,
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B, and A components, respectively.
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// refEnd VkBlendFactor
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[[framebuffer-blendconstants]]
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If the pipeline state object is created without the
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ename:VK_DYNAMIC_STATE_BLEND_CONSTANTS dynamic state enabled then the _blend
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constant_ [eq]#(R~c~,G~c~,B~c~,A~c~)# is specified via the
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pname:blendConstants member of slink:VkPipelineColorBlendStateCreateInfo.
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// refBegin vkCmdSetBlendConstants Set the values of blend constants
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Otherwise, to dynamically set and change the blend constant, call:
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include::../api/protos/vkCmdSetBlendConstants.txt[]
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* pname:commandBuffer is the command buffer into which the command will be
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recorded.
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* pname:blendConstants is an array of four values specifying the R, G, B,
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and A components of the blend constant color used in blending, depending
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on the <<framebuffer-blendfactors,blend factor>>.
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.Valid Usage
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****
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* [[VUID-vkCmdSetBlendConstants-None-00612]] The currently bound graphics pipeline must: have been created with the
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ename:VK_DYNAMIC_STATE_BLEND_CONSTANTS dynamic state enabled
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****
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include::../validity/protos/vkCmdSetBlendConstants.txt[]
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[[framebuffer-dsb]]
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=== Dual-Source Blending
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Blend factors that use the secondary color input
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[eq]#(R~s1~,G~s1~,B~s1~,A~s1~)# (ename:VK_BLEND_FACTOR_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
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ename:VK_BLEND_FACTOR_SRC1_ALPHA, and
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ename:VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA) may: consume hardware resources
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that could otherwise be used for rendering to multiple color attachments.
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Therefore, the number of color attachments that can: be used in a
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framebuffer may: be lower when using dual-source blending.
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Dual-source blending is only supported if the
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<<features-features-dualSrcBlend,pname:dualSrcBlend>> feature is enabled.
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The maximum number of color attachments that can: be used in a subpass when
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using dual-source blending functions is implementation-dependent and is
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reported as the pname:maxFragmentDualSrcAttachments member of
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sname:VkPhysicalDeviceLimits.
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When using a fragment shader with dual-source blending functions, the color
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outputs are bound to the first and second inputs of the blender using the
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code:Index decoration, as described in <<interfaces-fragmentoutput,Fragment
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Output Interface>>.
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If the second color input to the blender is not written in the shader, or if
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no output is bound to the second input of a blender, the result of the
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blending operation is not defined.
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[[framebuffer-blendoperations]]
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=== Blend Operations
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// refBegin VkBlendOp Framebuffer blending operations
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Once the source and destination blend factors have been selected, they along
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with the source and destination components are passed to the blending
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operation.
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The blending operations are selected from the following enum, with RGB and
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alpha components potentially using different blend operations:
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include::../api/enums/VkBlendOp.txt[]
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<<<
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The semantics of each enum value is described in the table below:
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.Blend Operations
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[width="100%",cols="45%,30%,25%",options="header",align="center"]
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|====
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|VkBlendOp | RGB Components | Alpha Component
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|ename:VK_BLEND_OP_ADD
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| [eq]#R = R~s0~ {times} S~r~ + R~d~ {times} D~r~# +
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[eq]#G = G~s0~ {times} S~g~ + G~d~ {times} D~g~# +
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[eq]#B = B~s0~ {times} S~b~ + B~d~ {times} D~b~#
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| [eq]#A = A~s0~ {times} S~a~ + A~d~ {times} D~a~#
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|ename:VK_BLEND_OP_SUBTRACT
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| [eq]#R = R~s0~ {times} S~r~ - R~d~ {times} D~r~# +
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[eq]#G = G~s0~ {times} S~g~ - G~d~ {times} D~g~# +
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[eq]#B = B~s0~ {times} S~b~ - B~d~ {times} D~b~#
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| [eq]#A = A~s0~ {times} S~a~ - A~d~ {times} D~a~#
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|ename:VK_BLEND_OP_REVERSE_SUBTRACT
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| [eq]#R = R~d~ {times} D~r~ - R~s0~ {times} S~r~# +
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[eq]#G = G~d~ {times} D~g~ - G~s0~ {times} S~g~# +
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[eq]#B = B~d~ {times} D~b~ - B~s0~ {times} S~b~#
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| [eq]#A = A~d~ {times} D~a~ - A~s0~ {times} S~a~#
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|ename:VK_BLEND_OP_MIN
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| [eq]#R = min(R~s0~,R~d~)# +
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[eq]#G = min(G~s0~,G~d~)# +
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[eq]#B = min(B~s0~,B~d~)#
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| [eq]#A = min(A~s0~,A~d~)#
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|ename:VK_BLEND_OP_MAX
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| [eq]#R = max(R~s0~,R~d~)# +
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[eq]#G = max(G~s0~,G~d~)# +
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[eq]#B = max(B~s0~,B~d~)#
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| [eq]#A = max(A~s0~,A~d~)#
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|====
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In this table, the following conventions are used:
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* [eq]#R~s0~, G~s0~, B~s0~# and [eq]#A~s0~# represent the first source
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color R, G, B, and A components, respectively.
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* [eq]#R~d~, G~d~, B~d~# and [eq]#A~d~# represent the R, G, B, and A
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components of the destination color.
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That is, the color currently in the corresponding color attachment for
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this fragment/sample.
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* [eq]#S~r~, S~g~, S~b~# and [eq]#S~a~# represent the source blend factor
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R, G, B, and A components, respectively.
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* [eq]#D~r~, D~g~, D~b~# and [eq]#D~a~# represent the destination blend
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factor R, G, B, and A components, respectively.
|
|
|
|
The blending operation produces a new set of values [eq]#R, G, B# and
|
|
[eq]#A#, which are written to the framebuffer attachment.
|
|
If blending is not enabled for this attachment, then [eq]#R, G, B# and
|
|
[eq]#A# are assigned [eq]#R~s0~, G~s0~, B~s0~# and [eq]#A~s0~#,
|
|
respectively.
|
|
|
|
If the color attachment is fixed-point, the components of the source and
|
|
destination values and blend factors are each clamped to [eq]#[0,1]# or
|
|
[eq]#[-1,1]# respectively for an unsigned normalized or signed normalized
|
|
color attachment prior to evaluating the blend operations.
|
|
If the color attachment is floating-point, no clamping occurs.
|
|
|
|
// refEnd VkBlendOp
|
|
|
|
If the numeric format of a framebuffer attachment uses sRGB encoding, the R,
|
|
G, and B destination color values (after conversion from fixed-point to
|
|
floating-point) are considered to be encoded for the sRGB color space and
|
|
hence are linearized prior to their use in blending.
|
|
Each R, G, and B component is converted from nonlinear to linear as
|
|
described in the "`KHR_DF_TRANSFER_SRGB`" section of the
|
|
<<data-format,Khronos Data Format Specification>>.
|
|
If the format is not sRGB, no linearization is performed.
|
|
|
|
If the numeric format of a framebuffer attachment uses sRGB encoding, then
|
|
the final R, G and B values are converted into the nonlinear sRGB
|
|
representation before being written to the framebuffer attachment as
|
|
described in the "`KHR_DF_TRANSFER_SRGB`" section of the Khronos Data Format
|
|
Specification.
|
|
|
|
If the framebuffer color attachment numeric format is not sRGB encoded then
|
|
the resulting [eq]#c~s~# values for R, G and B are unmodified.
|
|
The value of A is never sRGB encoded.
|
|
That is, the alpha component is always stored in memory as linear.
|
|
|
|
If the framebuffer color attachment is ename:VK_ATTACHMENT_UNUSED, no writes
|
|
are performed through that attachment.
|
|
Framebuffer color attachments greater than or equal to
|
|
sname:VkSubpassDescription::pname:colorAttachmentCount perform no writes.
|
|
|
|
|
|
[[framebuffer-logicop]]
|
|
== Logical Operations
|
|
|
|
The application can: enable a _logical operation_ between the fragment's
|
|
color values and the existing value in the framebuffer attachment.
|
|
This logical operation is applied prior to updating the framebuffer
|
|
attachment.
|
|
Logical operations are applied only for signed and unsigned integer and
|
|
normalized integer framebuffers.
|
|
Logical operations are not applied to floating-point or sRGB format color
|
|
attachments.
|
|
|
|
// refBegin VkLogicOp Framebuffer logical operations
|
|
|
|
Logical operations are controlled by the pname:logicOpEnable and
|
|
pname:logicOp members of slink:VkPipelineColorBlendStateCreateInfo.
|
|
If pname:logicOpEnable is ename:VK_TRUE, then a logical operation selected
|
|
by pname:logicOp is applied between each color attachment and the fragment's
|
|
corresponding output value, and blending of all attachments is treated as if
|
|
it were disabled.
|
|
Any attachments using color formats for which logical operations are not
|
|
supported simply pass through the color values unmodified.
|
|
The logical operation is applied independently for each of the red, green,
|
|
blue, and alpha components.
|
|
The pname:logicOp is selected from the following operations:
|
|
|
|
include::../api/enums/VkLogicOp.txt[]
|
|
|
|
<<<
|
|
|
|
The logical operations supported by Vulkan are summarized in the following
|
|
table in which
|
|
|
|
* [eq]#{lnot}# is bitwise invert,
|
|
* [eq]#{land}# is bitwise and,
|
|
* [eq]#{lor}# is bitwise or,
|
|
* [eq]#{oplus}# is bitwise exclusive or,
|
|
* [eq]#s# is the fragment's [eq]#R~s0~, G~s0~, B~s0~# or [eq]#A~s0~#
|
|
component value for the fragment output corresponding to the color
|
|
attachment being updated, and
|
|
* [eq]#d# is the color attachment's [eq]#R, G, B# or [eq]#A# component
|
|
value:
|
|
|
|
.Logical Operations
|
|
[width="75%",options="header",align="center"]
|
|
|====
|
|
|Mode | Operation
|
|
|ename:VK_LOGIC_OP_CLEAR | [eq]#0#
|
|
|ename:VK_LOGIC_OP_AND | [eq]#s {land} d#
|
|
|ename:VK_LOGIC_OP_AND_REVERSE | [eq]#s {land} {lnot} d#
|
|
|ename:VK_LOGIC_OP_COPY | [eq]#s#
|
|
|ename:VK_LOGIC_OP_AND_INVERTED | [eq]#{lnot} s {land} d#
|
|
|ename:VK_LOGIC_OP_NO_OP | [eq]#d#
|
|
|ename:VK_LOGIC_OP_XOR | [eq]#s {oplus} d#
|
|
|ename:VK_LOGIC_OP_OR | [eq]#s {lor} d#
|
|
|ename:VK_LOGIC_OP_NOR | [eq]#{lnot} (s {lor} d)#
|
|
|ename:VK_LOGIC_OP_EQUIVALENT | [eq]#{lnot} (s {oplus} d)#
|
|
|ename:VK_LOGIC_OP_INVERT | [eq]#{lnot} d#
|
|
|ename:VK_LOGIC_OP_OR_REVERSE | [eq]#s {lor} {lnot} d#
|
|
|ename:VK_LOGIC_OP_COPY_INVERTED | [eq]#{lnot} s#
|
|
|ename:VK_LOGIC_OP_OR_INVERTED | [eq]#{lnot} s {lor} d#
|
|
|ename:VK_LOGIC_OP_NAND | [eq]#{lnot} (s {land} d)#
|
|
|ename:VK_LOGIC_OP_SET | all 1s
|
|
|====
|
|
|
|
The result of the logical operation is then written to the color attachment
|
|
as controlled by the component write mask, described in
|
|
<<framebuffer-blendoperations,Blend Operations>>.
|
|
|
|
// refEnd VkLogicOp
|
|
|
|
[[framebuffer-color-write-mask]]
|
|
== Color Write Mask
|
|
|
|
// refBegin VkColorComponentFlagBits Bitmask controlling which components are written to the framebuffer
|
|
|
|
The pname:colorWriteMask member of slink:VkPipelineColorBlendAttachmentState
|
|
determines whether the final color values [eq]#R, G, B# and [eq]#A# are
|
|
written to the framebuffer attachment.
|
|
pname:colorWriteMask is any combination of the following bits:
|
|
|
|
include::../api/enums/VkColorComponentFlagBits.txt[]
|
|
|
|
If ename:VK_COLOR_COMPONENT_R_BIT is set, then the [eq]#R# value is written
|
|
to color attachment for the appropriate sample, otherwise the value in
|
|
memory is unmodified.
|
|
The ename:VK_COLOR_COMPONENT_G_BIT, ename:VK_COLOR_COMPONENT_B_BIT, and
|
|
ename:VK_COLOR_COMPONENT_A_BIT bits similarly control writing of the [eq]#G,
|
|
B,# and [eq]#A# values.
|
|
|
|
The pname:colorWriteMask is applied regardless of whether blending is
|
|
enabled.
|
|
|
|
// refEnd VkColorComponentFlagBits
|