[osg-users] RTT Camera does not render anything

[Christian Buchner]

Maybe you forgot to add the camera to the main scene graph?

An addChild() into the scene graph root should do the trick.


2015-04-14 15:16 GMT+02:00 Andreas Schreiber <ayss at online.de>:

> Hi
>
>
> I'm trying to generate a texture with a rtt-camera, so I can use this
> texture later in my main scene.
> To verify if the texture is correct I'm trying to put the texture on a
> quad in my main scene.
>
> I use the following method for the rtt-camera, the red clearColor I used
> to test what the camera renders, but it did not help me out.
>
>
> Code:
> osg::Camera *createRTTCamera(osg::Camera::BufferComponent buffer,
> osg::Texture *tex, bool isAbsolute)
> {
>     osg::ref_ptr<osg::Camera> camera = new osg::Camera;
>         osg::Vec4f textureStartColor = osg::Vec4f(1.0, 0.0, 0.0, 0.0);
>     camera->setClearColor(textureStartColor);
>     camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
>
> camera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
>     camera->setRenderOrder(osg::Camera::PRE_RENDER);
>
>     if (tex)
>     {
>         tex->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
>         tex->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);
>         camera->setViewport(0, 0, tex->getTextureWidth(),
> tex->getTextureHeight());
>         camera->attach(buffer, tex);
>     }
>     if (isAbsolute)
>     {
>         camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
>                 camera->setProjectionMatrix(osg::Matrix::ortho2D(0.0, 1.0,
> 0.0, 1.0));
>         camera->setViewMatrix(osg::Matrix::identity());
>                 osg::Vec3 corner = osg::Vec3();
>         camera->addChild(createScreenQuad(1.0f, 1.0f, 1, corner));
>     }
>     return camera.release();
> }
>
>
>
> In the main part I do the following:
>
> 1. I initialize the global texture2D variable with an image
>
> 2. Create the rrt camera with color_buffer, the texture (which is global),
> and 1 for absolute
>
> 3. load geometry
>
> 4.      Setup Light, here an example
>
> Code:
> osg::ref_ptr<osg::LightSource> sunLight = new osg::LightSource();
>         sunLight.get()->setLight(createLightSpot(osg::Vec4(0, 1, 0, 0),
> osg::Vec4(0, 1, 0, 1)));
>         sunLight.get()->setReferenceFrame(osg::LightSource::ABSOLUTE_RF);
>         sunLight.get()->setLocalStateSetModes(osg::StateAttribute::ON);
>
>
>
> 5. Add the light and the geometry to the rtt camera
> 6. Add the light and the geometry to the main scene
>
> Now there should be the scene on the quad geometry which I generated, but
> this is always rendered with the color of the light and nothing else on it.
> It isn't even a mix of the light color and the clear color of the rtt
> camera, its just the light color.
>
> Here is my quad generation as well:
>
> Code:
>         osg::ref_ptr<osg::Geode> planeRTT = new osg::Geode();
>         osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry();
>         planeRTT->addDrawable(geometry);
>
>         osg::ref_ptr<osg::Vec3Array> vertexArray = new osg::Vec3Array();
>         vertexArray->push_back(osg::Vec3(1, -0.25, -1));
>         vertexArray->push_back(osg::Vec3(1, 0.75, -1));
>         vertexArray->push_back(osg::Vec3(1, 0.75, 1));
>         vertexArray->push_back(osg::Vec3(1, -0.25, 1));
>         geometry->setVertexArray(vertexArray);
>
>         osg::ref_ptr<osg::Vec4Array> colorArray = new osg::Vec4Array();
>         colorArray->push_back(osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f));
>         geometry->setColorArray(colorArray);
>         geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
>
>         osg::ref_ptr<osg::Vec2Array> texCoordArray = new osg::Vec2Array();
>         texCoordArray->push_back(osg::Vec2(0.0f, 0.0f));
>         texCoordArray->push_back(osg::Vec2(1.0f, 0.0f));
>         texCoordArray->push_back(osg::Vec2(1.0f, 1.0f));
>         texCoordArray->push_back(osg::Vec2(0.0f, 1.0f));
>         geometry->setTexCoordArray(0, texCoordArray);
>
>         geometry->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLE_FAN, 0,
> 4));
>
>
> planeRTT.get()->getOrCreateStateSet()->setTextureAttributeAndModes(0,
> rttTexture.get(), osg::StateAttribute::ON);
>
>
>
> Did I miss something or did I mixed up some order?!
> Would be grateful for any help!
>
> ...
>
> Thank you!
>
> Cheers,
> Andreas
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=63381#63381
>
>
>
>
>
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