Heat effect

[Hamid Reza]

Hi,I want to make a heat effect.
I know that for do this work i must make a plane and get a picture from the back of the plane and set this picture
as the plane texture.Next use from a shader to wrap its texture;
But i don't know that how can i get a picture from the back of the plane?
I can do this work by "glCopyTexSubImage2D" or use from "Render to texture" method , but i want best and fastest way.
Please guide me. :confused:
Thank you for your attention.

[ZbuffeR]

Rendering to an FBO is more robust than copytexsubimage (which can break if parts of the rendering window are covered by other windows).
However copytexsub is very simple to implementent, so you may want to try it first.

[HannesH]

I would suggest writing a shader that does your effect to the entire screen in 2D.
You can use the stencil buffer to mask out areas that shouldn't have the heat effect applied