问题
I am trying to create something like effect system for OpenGL, and I want to be able to define a number of shaders in the same file. But I discovered the following problem. Say I have two shaders: A and B. Shader A uses texA and shader B uses texB. Then despite the fact that neither shader A uses texB nor shader B uses texA, both textures will be enumerated in both programs (I am using separate programs, so every shader corresponds to one program). One consequence is that I cannot have many textures defined in one file since the shader will fail to link (it compiles successfully but the linker then complains that the number of texture samplers exceeds the HW limit). Other problem is that I am doing automatic resource binding and my shaders have lots of false resource dependencies.
So is there a way to tell the shader compiler/linker to remove all unused resources from the separate program?
回答1:
Shader sampler units are not there to select textures, but to pass texture units to the shader. The textures themself are bound to the texture units. So the selection which texture to use should not be done in the shader, but in the host program.
Or you could use bindless textures if your OpenGL implementation (=GPU driver) supports these.
来源：https://stackoverflow.com/questions/29911554/how-to-remove-unused-resources-from-an-opengl-program