OpenGL ES : Pre-Rendering to FBO texture

Question

Is it possible to render to FBO texture once and then use the resulting texture handle to render all following frames?

For example, in case I'm rendering a hard shadow map and the scene geometry and light position are static, the depth map is always the same and I want to render it only once using a FBO and then just use it after that. However, if I simply put a flag to render the depth texture once, the texture remains empty for the rest of the frames.

Is FBO get reallocated after rendering a frame has been complete? What would be the right way to preserve rendered texture for rendering of the following frames?

Answer 1

Rendering to a texture is no different than if you had uploaded those pixels to the texture in the first place. The contents of a texture do not magically disappear. A texture's contents are changed when you change them. This could be by uploading data to the texture, or by setting one of the texture's images to be used for framebuffer operations (clearing, rendering to it, etc).

Unless you do something to explicitly change the data stored in a texture, it won't change.