Sets the number of output vertices for each input vertex, along with offsets into the layer and viewport lists.
- iOS 13.0+
- macOS 10.15.4+
- Mac Catalyst 13.4+
The number of outputs to create.
An optional parameter that specifies per-output offsets into the layer and viewport lists. If you provide a value for this parameter, you must provide the same number of entries as the count you specified.
By default, vertex amplification is not used. If you set a count greater than
1, each input vertex generates multiple output vertices (and correspondingly, each primitive becomes multiple output primitives). Typically, you use vertex amplification in conjunction with generating a render target index or viewport index inside your vertex shader, so that each output primitive is rendered to a distinct location.
If you specify view mappings, the render target index and viewport index are calculated by adding the offsets to the values provided by the vertex shader.