Spherical Area Light Fall-Off Attenuation

[adriansnetlis]

So currently this is how inverse squared calculation looks:
attenuation = 1.0 / pow(distance / the_distance_number_in_light_settings, 2); (it may look a bit different, but that's the math.
However, this does not provide the best results possible. Real lights have radius.
Sourcing for this(https://imdoingitwrong.wordpress.com/2011/01/31/light-attenuation/), you can calculate spherical area light attenuation by this calculation:
attenuation = 1.0 / pow(distance / radius + 1.0, 2);
If one wanted to keep the distance setting, radius can be multiplied by the distance number in light settings.
This is not very costly calculation by itself, however, the source provides even additional optimizations for deferred rendering.

Now adding "radius" option in light settings and switching to this equation could provide pretty nice results.

[panzergame]

Thanks for the detailed report, I leave it to new developer to get experience:
The fragment shader source/blender/gpu/shaders/gpu_shader_material.glslneed to be modified by adding a new attenuation function and a check added in gpu_material.c to select it.

[lordloki]

This was already implemented by @DCubix in the ge_brdf branch (eb97104#diff-cd270f0456f47fde6ee278bee899bdb7R1810). Maybe we can commit it to master.
I will test it.

[lordloki]

committed in master. Thanks for testing and proposal