viewportArrayIndexOffset
An offset into the list of viewports.
Declaration
var viewportArrayIndexOffset: UInt32Mentioned in
Discussion
To specify a list of offsets, call the setVertexAmplificationCount(_:viewMappings:) method.
When your app renders to different render targets, you specify the render target index to render to in your vertex shader by adding the viewport_array_index attribute to one of the vertex shader’s outputs. If you are using vertex amplification, Metal calculates the index for each amplified vertex by adding the index offset for the vertex to the value returned from your shader.