ShaderEffect seems to create a dummy texture when there is no texture provided. Although it is not sampled in the noise fragment shader, it is still waste of resources.
We want to use blend factors (One, One) instead of the default (One, OneMinusSrcAlpha) of the scene graph renderer. ShaderEffect does not allow adjusting these.
Disadvantages:
Not as simple as using ShaderEffect.
Request review @chub. If the noise is still different, the cause must not be about blending.
