RE: [www-vrml] combining textures and materials

["Bederov, Sergey" <bederov@parallelgraphics.com>]

	Hello Kay and Hermetic,
	If a coloured image is combined from three channels using
transparent layers, the result will be very dark or anyway have low
contrast. For example, to combine three layers with equal intensity:
   layer 1 (the lowest):    transparency=0
   layer 2 (in the middle): transparency=.5
   layer 3 (at the top):    transparency=.333
	You will get not the sum of three images, but their average. It is
three times darker than the original picture.
	Maybe the effect of combining texture and color can be achieved in
some other way? For example, you can illuminate the surface with a coloured
picture by a DirectionalLight with varying color. For the light not to
illuminate other geometry, it can be placed into a Group together with the
picture. And all other geometry hm... into an other Group, so that other
lights don't disturb the color.
                                        Sergey Bederov


-----Original Message-----
From: swe@cyworx.com [mailto:swe@cyworx.com]
Sent: Thursday, March 10, 2005 4:12 PM
To: www-vrml@web3d.org
Subject: RE: [www-vrml] combining textures and materials


Hi Kay,

this sounds like a very interesting stuff, do you have something online
to show this?

> You could solve the color issue, if you use three underlying planes,
> separate the color image to r,g,b components and texture every planes with
> one component, setting the planes transparent (maybe 0.5)... If you need
it
> dynamically, write a php script or a java servlet which sends the
requested
> component instead of accessing directly the image

gruesse

 	hermetic
-------------------------------------------------------------------------
for list subscription/unsubscription,
go to http://www.web3d.org/cgi-bin/public_list_signup/lwgate/listsavail.html