Sets a buffer for the fragment function.
- iOS 8.0+
- macOS 10.11+
- tvOS 9.0+
The buffer to set in the argument table.
How far the data is from the start of the buffer, in bytes.
The index in the buffer argument table.
For buffers in the device address space, the offset must be aligned to the data type consumed by the fragment shader function (which is always less than or equal to 16 bytes).
For buffers in the constant address space, the offset must be aligned to 256 bytes in macOS. In iOS, the offset must be aligned to the maximum of either the data type consumed by the tile shader, or 4 bytes. A 16-byte alignment is safe in iOS if you don't need to consider the data type.