114 lines
3.8 KiB
Plaintext
114 lines
3.8 KiB
Plaintext
// Copyright (c) 2014-2016 Khronos Group. This work is licensed under a
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// Creative Commons Attribution 4.0 International License; see
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// http://creativecommons.org/licenses/by/4.0/
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VkBlendOp(3)
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============
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Name
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----
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VkBlendOp - framebuffer blending operations
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C Specification
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---------------
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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. The blending operations are selected from the following enum,
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with RGB and alpha components potentially using different blend operations:
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include::../api/enums/VkBlendOp.txt[]
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Description
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-----------
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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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| latexmath:[$R=R_{s0}\times S_r+R_d\times D_r$] +
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latexmath:[$G=G_{s0}\times S_g+G_d\times D_g$] +
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latexmath:[$B=B_{s0}\times S_b+B_d\times D_b$]
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| latexmath:[$A=A_{s0}\times S_a+A_d\times D_a$]
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|ename:VK_BLEND_OP_SUBTRACT
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| latexmath:[$R=R_{s0}\times S_r-R_d\times D_r$] +
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latexmath:[$G=G_{s0}\times S_g-G_d\times D_g$] +
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latexmath:[$B=B_{s0}\times S_b-B_d\times D_b$]
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| latexmath:[$A=A_{s0}\times S_a-A_d\times D_a$]
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|ename:VK_BLEND_OP_REVERSE_SUBTRACT
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| latexmath:[$R=R_d\times D_r-R_{s0}\times S_r$] +
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latexmath:[$G=G_d\times D_g-G_{s0}\times S_g$] +
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latexmath:[$B=B_d\times D_b-B_{s0}\times S_b$]
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| latexmath:[$A=A_d\times D_a-A_{s0}\times S_a$]
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|ename:VK_BLEND_OP_MIN
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| latexmath:[$R=\min(R_{s0},R_d)$] +
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latexmath:[$G=\min(G_{s0},G_d)$] +
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latexmath:[$B=\min(B_{s0},B_d)$]
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| latexmath:[$A=\min(A_{s0},A_d)$]
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|ename:VK_BLEND_OP_MAX
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| latexmath:[$R=\max(R_{s0},R_d)$] +
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latexmath:[$G=\max(G_{s0},G_d)$] +
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latexmath:[$B=\max(B_{s0},B_d)$]
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| latexmath:[$A=\max(A_{s0},A_d)$]
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|==========================================
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In this table, the following conventions are used:
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- latexmath:[$R_{s0},G_{s0},B_{s0}$] and latexmath:[$A_{s0}$] represent
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the first source color R, G, B, and A components, respectively.
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- latexmath:[$R_d,G_d,B_d$] and latexmath:[$A_d$] represent the R, G, B,
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and A components of the destination color. That is, the color currently
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in the corresponding color attachment for this fragment/sample.
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- latexmath:[$S_r,S_g,S_b$] and latexmath:[$S_a$] represent the source
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blend factor R, G, B, and A components, respectively.
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- latexmath:[$D_r,D_g,D_b$] and latexmath:[$D_a$] represent the
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destination blend factor R, G, B, and A components, respectively.
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The blending operation produces a new set of values latexmath:[$R, G,
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B$] and latexmath:[$A$], which are written to the framebuffer attachment. If
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blending is not enabled for this attachment, then latexmath:[$R, G, B$] and
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latexmath:[$A$] are assigned
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latexmath:[$R_{s0},G_{s0},B_{s0}$] and latexmath:[$A_{s0}$], respectively.
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If the color attachment is fixed-point, the components of the source and
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destination values and blend factors are each clamped to
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latexmath:[$[0,1\]$] or latexmath:[$[-1,1\]$] respectively for an unsigned
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normalized or signed normalized color attachment prior to evaluating the
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blend operations. If the color attachment is floating-point, no clamping
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occurs.
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// refEnd VkBlendOp
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See Also
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--------
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slink:VkPipelineColorBlendAttachmentState
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Document Notes
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--------------
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For more information, see the Vulkan Specification at URL
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https://www.khronos.org/registry/vulkan/specs/1.0/xhtml/vkspec.html#VkBlendOp
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This page is extracted from the Vulkan Specification.
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Fixes and changes should be made to the Specification,not directly.
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include::footer.txt[]
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