Sharing texture among multiple shaders

railtracer95

I have multiple nodes on the screen. Each node has the same texture and uses a shader to modify the texture apperance. In order to be able to modify the parameters of the shader for each node separately, each node has a unique ShaderMaterial containing the shader.

In my shader I have the fragment function in which I read the UV color of the texture and using the passed parameters calculate the output color. As I understand reading the texture is not a cheap operation in shaders and since all my nodes have the same texture I have multiple unnecessary reads. Is there any way I can just read the texture once and pass it to all the shaders?

SIsilicon28

Sorry, but that's not how shaders work. Since you're using a different shader for different nodes, each material is going to have to call the texture sampling at least once per shader per mesh/sprite, i.e. once per node. Nonetheless, the GPU is most likely optimized to cache these texture reads anyway for faster subsequent access, but beyond that there's not much you can do about it.

Besides, have you checked if this "issue" slows down your game substantially, 'cause otherwise, your looking for an optimization that's not necessary.

Edit: Also, even if they all shared the same shader, they're still all calling the shader code separately. The only way to have this shader called once, is if all of the sprites/meshes were joined into one. This would count as only one shader call, but I doubt that would be such a good idea. Again, as long as this isn't causing any performance issues you should be in the clear. :)