My two cents...
Take the BMW M4 and start a session early in the morning, with the sun below the horizon.
In [GLARE], set :
LUMINANCE=1
THRESHOLD=1
BLOOM_LUMINANCE_GAMMA=1
SHAPE_LUMINANCE=1
SHAPE_BLOOM_LUMINANCE=very low (it depend on your exposure value)
In [GODRAYS], set:
LENGTH=0.001
In [TONEMAPPING] adjust exposure and gamma until you have something good.
Using Sol weather App, raise the sun to noon and change the previous [GLARE] settings in order to have the sun correctly illuminating the scene.
The higher BLOOM_LUMINANCE_GAMMA will be, the more distorded colors you will have.
The higher BLOOM_LUMINANCE_GAMMA will be, the more powerfull lights you will have.
The higher THRESHOLD will be, the more desaturated and dark colors you will have.
The higher THRESHOLD will be, the more objects will absorb light and have a volumetric touch.
You should play with [GLARE] until the enlightement, the sun shape and the colors seems correct.
Use BRIGHT_PASS to compare and see if the colors are not oversaturared, especially on dark road surfaces.
Adjust SHAPE_BLOOM_LUMINANCE to have the desired bloom level. It will also affect the sun corona. This can be adjust with GLARE_RATIO in [GODRAYS] and nerd__sun_adjust.ap_Level in lua
Always look at the rear stop lights of the M4 to see if there's not too much bloom.
Remember that total bloom = exposure ** (glare_luminance * glare_shape_luminance * glare_shape_bloom_luminance ** glare_bloom_luminance_gamma)
Once you are satisfied, adjust the godrays:
Set DEPTH_MASK_THRESHOLD = 1
Increase LENGTH and ANGLE_ATTENUATION until you have the godrays you want.
Now, go to Barcelona and set the sun just below the horizon and decrease DEPTH_MASK_THRESHOLD by very, vrey small steps. The sun should not pierce throught the mountains.
Finally, increase a bit ANGLE_ATTENUATION .
