lenore Is it possible to make it look like Spine's gamma color space in Unity without changing the color space settings?
Short answer: no. If it were possible in a reasonable way, we would do it automatically. It can't be done by e.g. performing some additional math in the shaders.
If you prefer Gamma space blending, it's highly recommended to use Gamma color space in your Unity project. Is there a reason why you don't want to change the Unity project setting?
If you really can't do that, your next best option would be to change the Spine Viewport settings to Linear to match your Unity project, as described here.
If you want to know why it's not possible:
The important part of the blending pipeline happens outside the shaders that we can control. With Linear color space active, all objects are rendered to a (linear) frame buffer (FBO / render texture) which is then at the end converted once from Linear to Gamma color space. What would be necessary, is to render all Spine skeleton objects to a custom render texture in Gamma space, and then convert the result to Linear space and render it to the normal scene. However, this workflow has the following major problems:
1) it only blends skeleton objects in gamma space, the resulting skeleton objects are blended with the scene in linear color space.
2) You can't interleave Gamma space skeletons and normal Linear scene objects.
3) It comes with an unnecessary performance overhead which is best avoided.
