UE4.26:How to get the direction of specific directional lights in custom node material? - #4 by Arkiras - Rendering - Epic Developer Community Forums
获取灯光位置的shader,应该是这个了atmosphere sun light vector 和vertexNormalWS的叉乘add一个固有色连接到emissive color上面。主意设置平行光的atmospheres sun light勾选,和advanced下面的atmospheres sun light Index
感觉类似这个。unity的ase_环境光增益
https://www.youtube.com/watch?v=hawiIan1vdA 油管上的UnlitFakeLight函数