ViewportMaskPerViewNV

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.