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Monday, October 31, 2016

Lighting guide part 4 addendum/clarification

So recently it was brought to my attention that the wording I used in my previous lighting guide was confusing or came across as flat out wrong.  This was specifically because I was trying to simplify the concept for a general audience.  As a result of this though I feel a clarification is in order.

Here's the post in question (I recommend reading it if nothing else for the excellent screenshots):

https://forum.game-guru.com/thread/216552?page=1#msg2561577

And the specific bit I want to address is here:

"Now on to what rubs me against the wolfish fur: Lee is wrong.

Quote: "The response was nothing less than astonishing. Lee told me outright that the brightness of the static lights is DIRECTLY tied to the bloom slider."


It isnt. I've been using mid level bloom settings around 50 in most of my scenes. I've only started to go higher because I was going for a washed out, hazy retro'ish look with recent efforts.
Seeing this I loaded up a large, completely lit map of mine and started to play with the bloom slider. I got the results I have expected. Bloom is just that. Bloom. While it adds a lot haze and shininess directly to light sources and bright surfaces it does not affect the lightmaps themselves
."

This is 100% correct.

THE ONLY VALUES THAT SHOULD EVER DIRECTLY INCREASE LIGHT POTENCY SHOULD BE THE ACTUAL LIGHT VALUES OF AMBIENT/SURFACE LIGHT.

My response was thus:

"Sorry if I was unclear - surface light value IS the primary driver for static light potency (as mentioned I think in my lighting guide, section 3) ... but bloom *DOES* have an impact on how bright those values appear. It's obvious the way I worded that in my 4th guide is a bit in error and will need a fix to clarify.

But basically I get what Lee was saying. Because of the additive effect bloom has on light values as rendered, it has an EFFECTIVE (as in not direct, but end result is similar) value of increasing the light's brightness.

Even wolf's example shows this very clearly:



Pay specific attention to the wall underneath the foremost blue column in the middle of the room. It very clearly is getting brighter.


So as you can see - the pillar in the middle is increasing in brightness per the renderer.  While the ACTUAL LIGHTMAPPING IS NOT CHANGED the appearance to the end user is that it is brighter.


Hope that clears things up!


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