[LayaAirIDE 2.0]为什么laya中的shader效果没用？

Shader error in 'LayaAir3D/Mesh/PBR(Specular)': undeclared identifier 'UnityDecodeCubeShadowDepth' at /Program Files/Unity/Editor/Data/CGIncludes/UnityShadowLibrary.cginc(98) (on d3d11)

Compiling Vertex program with POINT SHADOWS_CUBE SHADOWS_SOFT EnableReflection LIGHTMAP_OFF
Platform defines: UNITY_ENABLE_REFLECTION_BUFFERS UNITY_USE_DITHER_MASK_FOR_ALPHABLENDED_SHADOWS UNITY_PBS_USE_BRDF1 UNITY_SPECCUBE_BOX_PROJECTION UNITY_SPECCUBE_BLENDING UNITY_ENABLE_DETAIL_NORMALMAP SHADER_API_DESKTOP UNITY_COLORSPACE_GAMMA UNITY_LIGHT_PROBE_PROXY_VOLUME
 
我使用PBRshader的时候报这个错，请问有人知道吗？怎么解决？