Point Light Attenuation - Revision history

Mr F: /* Explanation */

2019-10-24T08:07:24Z

‎Explanation

2019-05-30T06:54:28Z

‎Explanation

2019-05-30T06:53:46Z

2019-05-30T06:53:29Z

2019-05-30T06:52:47Z

2019-05-30T06:52:21Z

‎Explanation

2019-05-30T06:47:41Z

‎Explanation

2019-05-30T06:33:49Z

‎What value should I use?

2019-05-30T06:29:05Z

‎Explanation

2019-05-30T06:24:56Z

‎Explanation

@@ Line 15: / Line 15: @@
 r = Light Range
-This is an arbitrary hand-tweaked function. It does in fact resembles the inverse square curve, except fixed at distance of 5 and then scaled based on Range parameter. It has a nice property of being exactly 1 in the center. Scaling the same gradient allowed Unity to even store it inside a texture. A 8-bit texture unfortunately, that also lacks precision and produces visible banding when rendering with gamma correction.
+This is an arbitrary hand-tweaked function. It does in fact resemble the inverse square curve, except fixed at distance of 5 and then scaled based on Range parameter. It has a nice property of being exactly 1 in the center. Scaling the same gradient allowed Unity to even store it inside a texture. A 8-bit texture unfortunately, that also lacks precision and produces visible banding when rendering with gamma correction.
 <hr>
 '''Bakery's "physical falloff"''' defaulted to a different formula:

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 {{note|Note that all mentioned renderers also include an additional range-based masking to slightly fade lighting away near the limit, as this is necessary for performance. But if range is set adequately to only kick in where the original falloff is dim, its effect is perceptually negligible}}
-{{note|Keep in mind that physical falloff is not scaled with Range, but mainly influenced by light’s brightness. It is highly recommended to enable tonemapper when setting up lights with physical falloff.}}
+{{note|Keep in mind that physical falloff is not scaled with Range, but mainly influenced by light’s brightness. It is highly recommended to enable tonemapper when using it.}}
 = What value should I use? =

@@ Line 2: / Line 2: @@
 [[File:Falloff graph.png|thumb|Comparison of different falloff curves]]
 [[File:Falloff comp.png|thumb|Perceptual comparison. Range = 20. Light intensity is set to 1 for Unity and 20 for Bakery to make them look as close as possible. Bottom row is tonemapped to compress bright values.]]
-[[File:Image8.png|thumb|Effect of Light Range on falloff.<br>Top: Unity (falloff is scaled).<br>Bottom: Bakery/HDRP/Frostbite/etc (falloff is slightly faded).]]
+[[File:Image8.png|thumb|Effect of Light Range on falloff.<br>Top: Unity (scales).<br>Bottom: Bakery/HDRP/Frostbite/etc (fades slightly).]]
 In real world, lighting attenuation is governed by the [https://en.wikipedia.org/wiki/Inverse-square_law inverse-square law]:
 [[File:Falloff ph.png]]

@@ Line 2: / Line 2: @@
 [[File:Falloff graph.png|thumb|Comparison of different falloff curves]]
 [[File:Falloff comp.png|thumb|Perceptual comparison. Range = 20. Light intensity is set to 1 for Unity and 20 for Bakery to make them look as close as possible. Bottom row is tonemapped to compress bright values.]]
-[[File:Image8.png|thumb|Effect of Light Range on falloff.<br>Top: Unity.<br>Bottom: Bakery/HDRP/Frostbite/etc.]]
+[[File:Image8.png|thumb|Effect of Light Range on falloff.<br>Top: Unity (falloff is scaled).<br>Bottom: Bakery/HDRP/Frostbite/etc (falloff is slightly faded).]]
 In real world, lighting attenuation is governed by the [https://en.wikipedia.org/wiki/Inverse-square_law inverse-square law]:
 [[File:Falloff ph.png]]

@@ Line 2: / Line 2: @@
 [[File:Falloff graph.png|thumb|Comparison of different falloff curves]]
 [[File:Falloff comp.png|thumb|Perceptual comparison. Range = 20. Light intensity is set to 1 for Unity and 20 for Bakery to make them look as close as possible. Bottom row is tonemapped to compress bright values.]]
-[[File:Image8.png|thumb|Effect of Light Range on falloff. Top: Unity. Bottom: everything else.]]
+[[File:Image8.png|thumb|Effect of Light Range on falloff.<br>Top: Unity.<br>Bottom: Bakery/HDRP/Frostbite/etc.]]
 In real world, lighting attenuation is governed by the [https://en.wikipedia.org/wiki/Inverse-square_law inverse-square law]:
 [[File:Falloff ph.png]]

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 = What value should I use? =
 When matching Bakery light to a HDRP light, Faloff min size will be automatically set to 0.01 to look identical.
-This value makes sense if your point light does indeed represent a 1cm emissive surface. However, there are cases when you'd better set it to a higher value:
+This value makes sense if your point light does indeed represent a 1cm emissive surface. However, there are cases when you can set it to a higher value:
 * When literally using point lights for larger surfaces (e.g. lamp of a traffic light).
 * When building for mobile platforms where lightmap compression is limited and cannot represent extremely bright values well; or tonemapping not possible.

← Older revision		Revision as of 06:29, 30 May 2019
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	[[File:Falloff bakery.png]]		[[File:Falloff bakery.png]]

−	With Light Size being 0.01, it looks similar to HDRP formula. With a value of 1 it works like the original Bakery falloff.	+	With Light Size being 0.01, it looks similar to HDRP formula, except instead of clamping it will slightly rescale the curve. With a value of 1 it works like the original Bakery falloff.