DrawIndex

DrawIndex

Decorating a variable with the DrawIndex built-in will make that variable contain the integer value corresponding to the zero-based index of the draw that invoked the current task, mesh, or vertex shader invocation. For indirect drawing commands, DrawIndex begins at zero and increments by one for each draw executed. The number of draws is given by the drawCount parameter. For direct drawing commands, if vkCmdDrawMultiEXT or vkCmdDrawMultiIndexedEXT is used, this variable contains the integer value corresponding to the zero-based index of the draw. Otherwise DrawIndex is always zero. DrawIndex is dynamically uniform.

When task or mesh shaders are used, only the first active stage will have proper access to the variable. The value read by other stages is undefined:.