如何使用Threejs实现逼真的反射

If you do not want to go to the Volumetric rendering then you have 3 options (I know of)

1. ray-tracing

   you have to use ray-trace rendering (back ray-trace) to achieve this. This will also cover shadows,transparent materials,reflected illumination and much more if coded properly. Unless you want to do also precise atmospheric scattering then this is the way.

   • back raytracing is one (or 3) ray(s) per each screen pixel. It is much faster but not that precise.. (still precise enough)
   • raytracing is one ray per each 3D angular unit (steradian) of space per each light source. It is slow but precise (if ray density is high enough).

   If the casted ray hits any obstacle then its color is changed (due to obstacle property) and new ray is casted as reflected light ray. If material is transparent then also refracted ray is casted ... Each hit or refraction affect light intensity so you stop when intensity is lower then some treshold or on some layer of recursion (limit max number of refractions per ray) to avoid infinite loops and you can manipulate performance/quality ...

2. standard polygon rendering

   With this approach (I think you are using it right now) you have to improvise. The reflection and illumination effects can be done similar to shadowing techniques. For each surface you have to render the scene in reflected direction. The same can be done with shadows but then you just rendering to the light direction or use shadow map instead. If you have insane number of reflective surfaces then this approach is not the way also to achieve reflection of refraction you have to render recursively making it multiple rendering pass per polygon which is also insane.

3. cubemap

   您可以对每个对象使用多维数据集映射。它与项目符号2相似，但是在生成立方体贴图时而不是在每帧中仅执行一次疯狂操作。如果对象太多，那么这也是不可行的。您只能将立方体贴图用于具有反射曲面的对象，以使其易于管理。另外，如果对象正在移动，则必须不时地重新生成立方体贴图。