[LayaAir3]求问在shader中多pass怎么设置剔除

Shader3D Start

{

    type:Shader3D

    name:PBRstroke

    enableInstancing:true,

    supportReflectionProbe:true,

    stateFirst:true,

    uniformMap:{

        

    },

    defines: {

        EMISSION: { type: bool, default: false },

        ENABLEVERTEXCOLOR: { type: bool, default: false }

    }

    shaderPass:[

        {

            stateFirst:true,

            pipeline:Forward,

            VS:LitVS,

            FS:LitFS,

            renderState:{

                cull:"Back",

            }

        },

        {

            stateFirst:true,

            pipeline:Forward,

            VS:LitVS1,

            FS:LitFS1,

            renderState:{

                cull:"Front",

            }

        }

    ]

}