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 and 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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0