fix the abnormal blink of ground under the dinosaur

[bigbearishappy]

I find that when the game is running.The ground under the dinosaur is always blink very fast.
I think it should not blink.This commit will fix this.

[ridoluc]

Hi. Thanks. Yes, that should do fix the issue.
Have you tested it? I can't test it right now.

[bigbearishappy]

Yes.I have already tested it on my own hardware.It works fine.