Hi,
Thanks for all the replies. My problem was solved by applying some sort of
perspective correction to my texture coordinates.
While creating the geometry I supplied a Vec3Array instead of a Vec2Array as
tex coord array. The tex coords that stay on short edge of the trapezoid, get a
z value of (len_short_edge / len_long_edge) whereas the the other tex coords
got 1.
Before sampling, the fragment shader divided the incoming tex coord vector by
its z. (In order to obtain a texture coordinate whose z is always 1).
I changed:
osg::Vec2Array *t = new osg::Vec2Array;
t->push_back(osg::Vec2(0, 0));
t->push_back(osg::Vec2(0, 1));
t->push_back(osg::Vec2(1, 1));
t->push_back(osg::Vec2(1, 0));
geom->setTexCoordArray(0, t);
to:
osg::Vec3Array *t = new osg::Vec3Array;
t->push_back(osg::Vec3(0, 0, 1));
t->push_back(osg::Vec3(0, 0.33f, 0.33f));
t->push_back(osg::Vec3(0.33f, 0.33f, 0.33f));
t->push_back(osg::Vec3(1, 0, 1));
geom->setTexCoordArray(0, t);
and used the following fragment shader:
uniform sampler2D sampler;
void main()
{
vec3 texCoord = gl_TexCoord[0];
gl_FragColor = texture2D(sampler, texCoord / texCoord.z);
}
Have a nice day,
Can
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=12874#12874
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
