1. Homework Tips

2. We will learn What actions are Apply actions to a node or a path Compute 3D bounding box Compute cumulative transformation matrix Insert callbacks for GLRender action

3. Actions We learned how to build the scene graph We saw the most commonly used action –GL Rendering

4. Applying action Action is applied to a node The graph rooted by the node is traversed Each node implements its own behavior Initialize the action Apply Obtain the results

5. Bounding box // Initilization. If use new, use also delete SbViewportRegion vpr = viewer->getViewportRegion(); SoGetBoundingBoxAction bboxAction (vpr); // Apply action to a pointer to node bboxAction.apply(node); // Obtain results bboxAction.getCenter(); bboxAction.getBoundingBox(); // aligned with XYZ bboxAction.getXFBoundingBox(); // The most accurate

6. Transformation matrix // Initilization SoGetMatrixAction mtxAction; // Apply to transformation node or to a path mtxAction.apply(transformation node) // Obtain results mtxAction.getMatrix(); mtxAction.getInverse();

7. GLRender callbacks Inventor Toolmaker, chapter 2. Define your class: class MyClass: public SoNode{ // Callback for rendering virtual void GLRender(SoGLRenderAction *action); } Implement GLRender() in Cpp file void GLRender(SoGLRenderAction *action){ SoNode::GLRender(action); // Important to call the original }