Hi,

I've managed to implement a reasonally flexible lighting shader, including both directional and point lights. With various numbers of max. lights (different copies of the effect/shader).

But there's something strange with the light attenuation of my point lights.
For testing purposes I've set up the following scene:

- place a point light at position x (-5, 1, 5)

- give the point light a max. range of 5.0, fullpower (full bright) range of 3.0

- place a sphere with blended material at position x (-5, 1, 5)

And then simply check if the point light stops shining where the sphere begins.

Unfortunately... it doesn't.

I've double checked the range/scale of the sphere, it matches the 5 'units' in the same scale as the pointlight range of '5'.

Here's a screenshot of the result and the actual attenuation calculation.

Any idea where it's going wrong?

// PER PIXEL ATTENUATION
float dist = length(PointLightPos[i] - input.wPos);
float att = saturate(1 - (dist - PointLightFPRange[0]) / (PointLightRange[0] - PointLightFPRange[0]));
att *= att;

Hi unbird,

I've got it, also wrote it down with some examples on paper.

My dummy explanation is that I take fully lit (1.0) minus the range that's attenuated divided by the total attenuation range.

Here are 2 screenshots with a point light with range 5, one with fullpower range also 5 and one with FP range 2.

There's still some more brighter light in the center in the 5 / 2 example, but that's probably because of the Y position of the light, above the terrain (the light being a sphere).

I'm also trying to find out why I do the attenuaton in the power of 2 (att = att * att).

Any idea?

Thanks.

I've now added the "att *= att" because indeed it smoothens things.

It also looks good for my goal now and the range is as I expect.