I create a Shadow Volume,It is OK when i don't move the camera,But when i move the camera ,the shadow will disappear.I ask someone else

whether it is normal,he said Yes.Did anyone encounter a problem like this,HOW to solve.(I use z_fail algorithm).

You will need to give us more than just a picture, most likely, if you want a solution.

I would start by debuging the vertices that make up your shadow volume, and find out what is going to with them in the shader when the camera moves. It looks to me like some of the shadow volume is being clipped against the near plane, but I'm just guessing here.

Does this happen only when the camera is inside the shadow? this happened in my game, although i didn't mind it much, but i think they're a way to fix it, but yea, we need more information than that.

IIRC, this is only an issue with depth pass shadow volumes, depth fail,(aka Carmack's reverse) should not suffer from this.

Well.I find the problem,My color mask is wrong.The final color mask should be dynamic.