Hello,
In my current project, I have 3 slave cameras rendering to texture with
offsets in their view matrices, and then another camera reassembling the
images with a deformation to map it onto a half-sphere dome (similar to
osgdistortion --dome). I'm trying to fix the problem where
view-dependent shading is wrong because the shading uses the slave
camera's offset view matrix instead of the master camera's view matrix.
You can also see this problem in osgdistortion --dome cow.osg, if you
move the cow so that it's on the junction of two cameras, the reflection
mapping shows the junction.
What I'm doing is, right before the draw traversal, I call a function
like this:
void MyClass::updateViewMatrices(osgViewer::CompositeViewer* viewer)
{
for (unsigned int i = 0; i < viewer->getNumViews(); i++)
{
osg::Camera* camera = viewer->getView(i)->getCamera();
osg::StateSet* stateset = camera->getOrCreateStateSet();
osg::Uniform* viewMatrixUniform =
stateset->getUniform("my_CameraViewMatrix");
if (!viewMatrixUniform)
{
viewMatrixUniform =
new osg::Uniform("my_CameraViewMatrix",
camera->getViewMatrix());
stateset->addUniform(viewMatrixUniform);
}
else
{
viewMatrixUniform->set(camera->getViewMatrix());
}
}
}
So this should set a uniform with the main camera's view matrix, which I
will want to use in the shader when rendering the slave cameras' views.
My vertex shader looks like this:
uniform mat4 osg_ViewMatrixInverse; // according to glsl_quickref.pdf
uniform mat4 my_CameraViewMatrix;
// ...
void main (void)
{
// Calculate the model view matrix relative to the main camera.
mat4 modelMatrix = gl_ModelViewMatrix * osg_ViewMatrixInverse;
mat4 modelViewMatrix = modelMatrix * my_CameraViewMatrix;
// Eye-coordinate position of vertex, needed in various calculations
// Use our modelview matrix instead of gl_ModelViewMatrix.
vec4 ecPosition = modelViewMatrix * gl_Vertex;
// Do fixed functionality vertex transform
gl_Position = ftransform();
// ...
// Use ecPosition for shading, shadows and fog
// ...
}
Is there any reason why this shouldn't work?
What I see is that shadows and fog aren't in the right place, and
anyways it doesn't fix the view-dependent shading issue I was trying to
fix... I suspect my math is wrong (it often is) but I can't spot the
problem.
Suggestions welcome.
J-S
--
______________________________________________________
Jean-Sebastien Guay [EMAIL PROTECTED]
http://www.cm-labs.com/
http://whitestar02.webhop.org/
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