# ViewportMaskPerViewNV(3) Manual Page

## Name

ViewportMaskPerViewNV - Mask of viewports broadcast to per view

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## Description

`ViewportMaskPerViewNV`

  Decorating a variable with the `ViewportMaskPerViewNV` built-in decoration will make that variable contain the mask of viewports primitives are broadcast to, for each view.

  The value written to an element of `ViewportMaskPerViewNV` in the last pre-rasterization shader stage is a bitmask indicating which viewports the primitive will be directed to. The primitive will be broadcast to the viewport corresponding to each non-zero bit of the bitmask, and that viewport index is used to select the viewport transform, scissor rectangle, and exclusive scissor rectangle, for each view. The same values must be written to all vertices in a given primitive, or else the set of viewports used for that primitive is undefined.

  Elements of the array correspond to views in a multiview subpass, and those elements corresponding to views in the view mask of the subpass the shader is compiled against will be used as the viewport mask value for those views. `ViewportMaskPerViewNV` output in an earlier pre-rasterization shader stage is not available as an input in the subsequent pre-rasterization shader stage.

  Although `ViewportMaskNV` is an array, `ViewportMaskPerViewNV` is not a two-dimensional array. Instead, `ViewportMaskPerViewNV` is limited to 32 viewports.

Valid Usage

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04412
  The `ViewportMaskPerViewNV` decoration must be used only within the `Vertex`, `MeshNV`, `TessellationControl`, `TessellationEvaluation`, or `Geometry` `Execution` `Model`

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04413
  The variable decorated with `ViewportMaskPerViewNV` must be declared using the `Output` `Storage` `Class`

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04414
  The variable decorated with `ViewportMaskPerViewNV` must be declared as an array of 32-bit integer values

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04415
  The array decorated with `ViewportMaskPerViewNV` must be a size less than or equal to 32

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04416
  The array decorated with `ViewportMaskPerViewNV` must be a size greater than the maximum view in the subpass’s view mask

- VUID-ViewportMaskPerViewNV-ViewportMaskPerViewNV-04417
  The array variable decorated with `ViewportMaskPerViewNV` must only be indexed by a constant or specialization constant

## See Also

No cross-references are available

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0