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Fractal Software => Fragmentarium => Topic started by: Crist-JRoger on September 02, 2016, 09:23:19 PM




Title: Natural shadow blur
Post by: Crist-JRoger on September 02, 2016, 09:23:19 PM
A question to GLSL guru  :embarrass: So everybody knows that Eiffie's shadows in DE-renderer are very quick and looks great. Is there a some way to create natural realistic smooth of shadow? I mean "bokeh"-looked effect when shaded object is far from source of shadow (sorry for bad English)
Examples to understand what I mean:

(http://radojuva.com/wp-content/uploads/2012/08/nature-prototipe-bokeh.jpg)

(https://synergiscad.files.wordpress.com/2013/07/gb4.jpg)

(http://image.shutterstock.com/z/stock-photo-tree-shadow-on-white-wall-389357242.jpg)


Title: Re: Natural shadow blur
Post by: knighty on September 02, 2016, 09:40:41 PM
 :)


Title: Re: Natural shadow blur
Post by: Crist-JRoger on September 02, 2016, 09:45:54 PM
I know, I want too much from the free program  88)


Title: Re: Natural shadow blur
Post by: hobold on September 09, 2016, 10:33:35 AM
The technical term for the phenomenon you mention is "penumbra" (in case you want to wikipedia or google).

It is caused by the sun (or the respective light source) being larger than a single point. Therefore, being in light or being in shadow is not a binary yes/no decision - the sun can be partially visible from a point on the surface. When that happens, this surface point is partially in shadow and partially in light.

Most rendering software models light sources as single points; that is simple and quick to compute. Simulating a more realistic light source is not so easy, especially not when one wants to add it as an isolated feature to an existing renderer. Conceptually it is simpler to program a more complete simulation of light, then penumbra are inherently part of the rendered images. But that is a lot of work, too - and the method does require quite a bit of computation.


Title: Re: Natural shadow blur
Post by: Crist-JRoger on September 09, 2016, 08:41:19 PM
DE renderer (one of last updates) has sun - SpotLight; and sun has size - LightSize; and objects has shadows HardShadow, shadows calculates with distance, so they have some soft edges. I'm not a programmer, but I think that just need to change blur algorithm and link it to size of sun + distance. No?  :-\ I don't say that it's too easy, but it is not so bad

About isolated features - I can not agree with you. Look at DE-Raytracer and DE-Kn or DE-PK  :dink:


Title: Re: Natural shadow blur
Post by: SCORPION on October 05, 2016, 01:11:08 AM
Сергей, на деми личку проверь