Re: [osg-users] texture sampler uniforms

Sergey Polischuk Wed, 21 Mar 2012 01:45:09 -0700

Hi Daniel

It is ok by spec to use sampler when texture is not bound, but it can easily crash on bad drivers (i've had such crashes on intel cards)

You can create 1x1 pixel white texture and set on all scene on all first four texture units. It will apply only to those nodes which dont have their own textures set on appropriate units and wont change textures that are in place, so you can use your shader code

Cheers, Sergey

21.03.2012, 11:59, "Daniel Schmid" <[email protected]>:

I would like to build a generic fragment shader that can handle up to 4 texture units, instead of building fragment shaders for each number of used texture units.
Is there a way to figure out in my fragment shader if a texture unit is used or not ? When a uniform sampler contains no valid texture, it seems that its values are 0. And by fragment code like

                vec4 color = texture2D( baseTexture, gl_TexCoord[0].xy );
                color *= texture2D( baseTexture2, gl_TexCoord[1].xy );
                color *= texture2D( baseTexture3, gl_TexCoord[2].xy );
               color *= texture2D( baseTexture4, gl_TexCoord[3].xy );

the fragments get black as soon as a uniform sampler is not bound to a texture…

Von: [email protected] [mailto:[email protected]] Im Auftrag von Sergey Polischuk
Gesendet: Dienstag, 20. März 2012 16:50
An: OpenSceneGraph Users
Betreff: Re: [osg-users] texture sampler uniforms

Hi

you need to manually create them and add to statesets. If you'll save model after that - they will be saved correctly and will be there on model load.

20.03.2012, 17:15, "Daniel Schmid" <[email protected]>:
Hi there
I was searching osg to find out what happens with textures when a model node is loaded from file (for example openflight *.flt model). Does osg automatically create uniforms samplers for shaders to access the textures? Do these uniforms have specific names ? or do I have to manually create and bind uniforms for the textures ?

Regards
Daniel

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Re: [osg-users] texture sampler uniforms

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