Issue with lighting

[Methew5]

Hi.
I tried to use two options of LightEstimationConfig: Spectacular & Disabled.
In two cases I faced a problem:
1)Spectacular: when moving away, the model becomes darker
https://user-images.githubusercontent.com/69910337/145591863-d3eeb7fc-9d99-4814-b3b1-7219164da1a9.mp4
2)Disabled: on different walls, I have different colors of the model
https://user-images.githubusercontent.com/69910337/145591838-2c8350df-48ea-449b-839a-d372768a516e.mp4
@ThomasGorisse, or someone else, do you know, how can I fix that? Is it possible?

[ThomasGorisse]

Hi @Methew5 ,

Welcome to the light estimation world.

1)Spectacular: when moving away, the model becomes darker
https://user-images.githubusercontent.com/69910337/145591863-d3eeb7fc-9d99-4814-b3b1-7219164da1a9.mp4

This is a "normal" behavior since your room seems very dark.
ARCore is updating the estimation while you go backward from the wall.
It first (when only seeing a white wall and nothing else) think it's a quite lighted room but estimate it more precisely when you give it more infos about the real environment (backing ward from the wall and seeing more dark things around)
LightEstimationConfig.SPECTACULAR vs LightEstimationConfig.REALISTIC mostly differs on the reflections parts and you will mainly only see differences if your model has more metallic than roughness material values.
Adjust the based reference/factored lighting values with:

sceneView.mainLight.intensity

and

sceneView.environment.indirectLight.intensity

2)Disabled: on different walls, I have different colors of the model
https://user-images.githubusercontent.com/69910337/145591838-2c8350df-48ea-449b-839a-d372768a516e.mp4

This can be due to 2 things I think:

• The main directional light introduced with LightEstimation is also available in a LightEstimation.DISABLED context but kept fixed at the default Filament location/orientation and default indoor standard intensity as a normal non AR usage.
  

  sceneform-android/core/src/main/java/com/gorisse/thomas/sceneform/light/Light.kt

  Lines 8 to 11 in f05ef5b

  	/**
  	* Default directional light intensity.
  	*/
  	const val defaultMainLightIntensity = 5_000.0f

  
  So you can try to reduce it and the sceneView.environment.indirectLight intensity or call sceneView.mainLight = null if you want to completely disconnect what you are trying to render with the scene lighting but your planes will be less visible.
• You are maybe using the baseColorFactor instead of the emissiveColorFactor which may more correspond to what you are trying to achieve. Have a look at the cursor.blend used by SceneView to inspect what material you should define to have a light independent color.

That being said, you can act on multiple things moreover then just modifying the LightEstimationConfig mode:

sceneform-android/core/src/main/java/com/gorisse/thomas/sceneform/light/LightEstimation.kt

Lines 39 to 96 in c4ed1ba

	/**
	* ### The behavior of the lighting estimation subsystem.
	*
	* These modes consist of separate APIs that allow for granular and realistic lighting
	* estimation for directional lighting, shadows, specular highlights, and reflections.
	*/
	val mode: Config.LightEstimationMode = Config.LightEstimationMode.ENVIRONMENTAL_HDR,
	/**
	* ### Enable reflection cubemap
	*
	* - true if the AR Core reflection cubemap should be used
	* - false for using the default/static/fake environment reflections
	*
	* Use the HDR cubemap to render realistic reflections on virtual objects with medium to high
	* glossiness, such as shiny metallic surfaces. The cubemap also affects the shading and
	* appearance of objects. For example, the material of a specular object surrounded by a blue
	* environment will reflect blue hues. Calculating the HDR cubemap requires a small amount of
	* additional CPU computation.
	*/
	val environmentalHdrReflections: Boolean = true,
	/**
	* ### Ambient spherical harmonics
	*
	* In addition to the light energy in the main directional light, ARCore provides spherical
	* harmonics, representing the overall ambient light coming in from all directions in the scene.
	* Add subtle cues that bring out the definition of virtual objects.
	*/
	val environmentalHdrSphericalHarmonics: Boolean = true,
	/**
	* ### SpecularFilter applies a filter based on the BRDF used for lighting
	*
	* Specular highlights are the shiny bits of surfaces that reflect a light source directly.
	* Highlights on an object change relative to the position of a viewer in a scene.
	*
	* `true` = Reduce the amount of reflectivity a surface has. It is a key component in determining
	* the brightness of specular highlights, along with shininess to determine the size of the
	* highlights.
	*/
	val environmentalHdrSpecularFilter: Boolean = true,
	/**
	* ### Move the directional light
	*
	* When the main light source or a lit object is in motion, the specular highlight on the
	* object adjusts its position in real time relative to the light source.
	*
	* Directional shadows also adjust their length and direction relative to the position of the
	* main light source, just as they do in the real world.
	*/
	val environmentalHdrMainLightDirection: Boolean = true,
	/**
	* ### Modulate the main directional light (sun) intensity
	*/
	val environmentalHdrMainLightIntensity: Boolean = true

Finally, have a look at the sample app for adjusting your desired values:

[Methew5]

@ThomasGorisse, thank you for your advice and time.
First of all, I consider the Spectacular config.
I have already tried all HDR options, created different custom configs, but it didn't help.
Increasing indirect light intensity leads to a very bright model when the room is lit well.
Changing the main light intensity gives nothing.
But overall, the Spectacular config gives good results.
Thank you very much again, I really appreciate your work.