MTLStepFunction.constant The function fetches attribute data once. Declarationcase constant See AlsoStep optionsMTLStepFunction.perInstanceMTLStepFunction.perPatchMTLStepFunction.perPatchControlPointMTLStepFunction.perVertexMTLStepFunction.threadPositionInGridXMTLStepFunction.threadPositionInGridYMTLStepFunction.threadPositionInGridXIndexedMTLStepFunction.threadPositionInGridYIndexed