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Awesome job so far everyone! Please give us your feedback on how our article efforts are going. We still need more finished articles for our May contest theme: Remake the Classics

#Actualt_guen03

Posted 19 February 2012 - 07:21 AM

Hi,
thank your for your responses.

You're the first to address to my be my last name only Posted Image
And I've been in these forums since 2006 ;)


Yey, im the first one : )

You seem to think that if one of the vertices has z > 1 then the triangle can't be rasterized on screen, it doesn't work like that.


Yes i realy thought this way, thanks for making this clear.

The shadow volume covers everything except what you've shaded.


But wouldn't this be false either. The shadow volume would enclose more objects then it should (Ok, in my sketch there is only one object, but if there would be more, then the shadow volume would enclose objects which were originally not shadowed)
The situation gets even worse, when you think about a shadow volume perpendicular to the z axis in eye space.

ViewSpace2

ClipSpace2


I wonder, why this behaviour is never mentioned in texts describing stencil shadows. Sketches i saw are just extruding the shadow volumes in eyespace where everything looks fine, but in clipspace i got this mess, where everything goes to the far plane.

#2t_guen03

Posted 18 February 2012 - 06:41 AM

Hi,
thank your for your responses.

You're the first to address to my be my last name only Posted Image
And I've been in these forums since 2006 ;)


Yey, im the first one : )

You seem to think that if one of the vertices has z > 1 then the triangle can't be rasterized on screen, it doesn't work like that.


Yes i realy thought this way, thanks for making this clear.

The shadow volume covers everything except what you've shaded.


But wouldn't this be false either. The shadow volume would enclose more objects then it should (Ok, in my sketch there is only one object, but if there would be more, then the shadow volume would enclose objects which were originally not shadowed)
The situation gets even worse, when you think about a shadow volume perpendicular to the z axis in eye space.

ViewSpace2

ClipSpace2


I wounder, why this behaviour is never mentioned in texts describing stencil shadows. Sketches i saw are just extruding the shadow volumes in eyespace where everything looks fine, but in clipspace i got this mess, where everything goes to the far plane.

#1t_guen03

Posted 18 February 2012 - 06:37 AM

Hi,
thank your for your responses.

You're the first to address to my be my last name only :)
And I've been in these forums since 2006 ;)


Yey, im the first one : )

You seem to think that if one of the vertices has z > 1 then the triangle can't be rasterized on screen, it doesn't work like that.


Yes i realy thought this way, thanks for making this clear.

The shadow volume covers everything except what you've shaded.


But wouldn't this be false either. I mean like you said, then the shadow volume is enclosing more objects as it should (Ok in my sketch is only one object, but if there would be more then it would enclose objects which were not originally in the shadow)
The situation gets even worse, when you think about a shadow volume perpendicular to the z axis in eye space.

ViewSpace2

ClipSpace2


I wounder, why this behaviour is never mentioned in texts describing stencil shadows. Sketches i saw are just extruding the shadow volumes in eyespace where everything looks fine, but in clipspace i got this mess, where everything goes to the far plane.

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