Alright, I have checked your article and the paper mentioned (PSSM), thanks for the pointer.

 

So If I have well understood:

 

In a first time you render all the shadowmap for your game:

Render Shadowmap for projected ligt

Render Shadowmap for omni light with cubemap or multiple frustum

Etc…

Render Cascaded Shadowmap for the sun light (with day and light cycle managed):

    Here for the directional light representing the Sun

    you render 4 Shadowmap for each 4 frustum slice transformed in light space in one texture (aka texture atlas)

 

Now render all gathered Shadowmap in a preprocess (Deferred Shadowing) -> Shadow collector

   Render each Shadowmap collected from the viewer point of view and store the shadow factor in a screen-sized texture

   Render Cascaded Shadowmap (Put the 4 light space matrix in constant register and select the right light projection to use via compare/dot product)

   And store the shadow factor…

 

When you said to store shadow factor in r, g or b channel, you mean that the different shadow factor must not be blend together and should be left separated

Until they are use for lighting calculation ? So in the above description, spot light should be render in r channel and cascaded in g, then at lighting do two texture fetch ?

And I not understand why shadow collector is the z-prepass, don’t you need to do a z-prepass before to render in the shadow collector,

You can save a lot of compare and texture fetch or I missed something ?

 

Thanks for your help.

 

Lagarde Sébastien

Software engineer

Neko entertainment

 

 


De : gdalgorithms-list-bounces@lists.sourceforge.net [mailto:gdalgorithms-list-bounces@lists.sourceforge.net] De la part de Wolfgang Engel
Envoyé : mercredi 4 avril 2007 14:34
À : 'Game Development Algorithms'
Objet : Re: [Algorithms] Deferred shadow mask generation

 

Oh and the shadow collector pass is the Z pre-pass …

 

From: gdalgorithms-list-bounces@lists.sourceforge.net [mailto:gdalgorithms-list-bounces@lists.sourceforge.net] On Behalf Of Lagarde Sébastien
Sent: Wednesday, April 04, 2007 4:55 AM
To: gdalgorithms-list@lists.sourceforge.net
Subject: [Algorithms] Deferred shadow mask generation

 

Hello,

I heard that the Crytech engine2 use a specific technique they call “deferred shadow mask generation” for blend all shadow buffer in one shadow buffer

Then practice a “smart blur” on it to get soft shadows.

This mask is then reuse later to render shadow in the scene.

 

Anyone heard about a similar technique like this or have some information on how to gather many shadow buffer in one ?

 

Thank you.

 

Lagarde Sébastien

Software engineer

Neko entertainment