'Glow-y' effect on some materials after color transition

[afauch]

Found by @rckmnt

Using method
gameObject.SetColor("#FF0000", 0.8f);

Material Before Transition

Material After Transition

[afauch]

A couple of things I'm noticing @rckmnt

• The key thing contributing to this 'glow-y' effect seems to be the fact that the different faces of the cube are not shaded according to light. In the GIF this lack of shading appears to be true on all of the red material instances after transition, though the camera perspective makes it hard to be 100% sure.
• I'm noticing that the yellow cube in particular doesn't seem to be shaded by side prior to transition. This makes me wonder whether there are some lighting settings at play here.
• I'm noting that the object is still casting shadows, which means it's probably still interacting with light buffers in some way.
• The only difference in materials I could see between your example and my example below is that you don't have Specular Highlights or Reflections checked on your Forward Rendering Options. I'm curious whether checking those would have any effect.

My attempt to repro (no glow-y issue)

Before

After

Some shots in the dark:

Hypothesis 1
This has to do with your project-level lighting / quality settings (Edit > Project Settings > Quality). Maybe shading the "Fade" render mode isn't being respected by the quality settings under your current build target platform.

Hypothesis 2
This issue has to do with Forward/Deferred Rendering, and the differences are caused when a material is swapped from "Opaque" to "Fade" rendering mode without Forward Rendering turned on. I don't know much about this - just started reading about it here. What you're seeing seems similar to what happens when Color Buffer is active without including Depth Buffer and Normal Buffer.

[afauch]

Haven't read this but may also be relevant:
http://polycount.com/discussion/158129/unity-5-standard-shader-transparent-issue-see-2min-vid

[afauch]

Related, but not a solution: Unity docs on Transparent vs Fade render modes
https://docs.unity3d.com/Manual/StandardShaderMaterialParameterRenderingMode.html

[afauch]

Logging my attempts to repro:

• Turning off Specular Highlights and Reflections did not repro.
• Changing Smoothness=0 did not repro.
• Removing Skybox did not repro.
• Changing Quality Settings to Very Low did not repro.

Hypothesis 1 disproved.