Graphics Graphics Korea University cgvr.korea.ac.kr 1 Applying Actions 강 신 진

CGVR Graphics Korea University cgvr.korea.ac.kr 2 Inventor Actions General Model Applying an Action Rendering Calculating a Bounding Box Accumulating a Transformation Matrix Writing to a File Searching for a Node Picking Contents

CGVR Graphics Korea University cgvr.korea.ac.kr 3 Inventor Actions Available Action List Using This ActionYou Can Perform This Task SoGetBoundingBoxActionCompute a 3D bounding box SoGetMatrixAcionCompute a transformation matrix SoWriteActionWrite Scene graph to a file SoSearchActionSearch for paths to specific nodes SoHandleEventActionAllow object to handle an event SoRayPickActionPick object in the scene graph along a ray SoCallBackActionTraverse the scene graph and perform your own action using callback function SoGLRenderAction Draw, or render, the scene graph

CGVR Graphics Korea University cgvr.korea.ac.kr 4 General Model Initialize the action SbViewportRegion region(300, 200); SoGLRenderAction renderAction(region); Set up special parameters for the action SoGLRenderAction renderAction(region, TRUE); Apply the action to a node renderAction->apply(root) Obtain the result of the action, if possible

CGVR Graphics Korea University cgvr.korea.ac.kr 5 Applying an Action Action Application Node Path Path list Traversal state Internal class to store transient state elements Inventor database management

CGVR Graphics Korea University cgvr.korea.ac.kr 6 Rendering - Execution Execution of SoGLRenderAction If the node is a group >>Visit each children If the node is a property group >>Replace a value of traversal state If the node is derived from SoTransformation >>Modify the current transformation If the node is shape node >>Draw shape using the current element

CGVR Graphics Korea University cgvr.korea.ac.kr 7 Rendering - Transparency Setting the Transparency Quality setTransparencyType() Transparency Levels  SCREEN_DOOR  ADD  DELAYED_ADD  SORTED_OBJECT_ADD  BLEND  DELAYED_BLEND  SORTED_OBJECT_BLEND

CGVR Graphics Korea University cgvr.korea.ac.kr 8 Rendering - Antialiasing 2 Types of Antialiasing Smoothing Using the Accumulation Buffer Smoothing SoGLRenderAction :: setSmoothing(SbBool smooth) Accumulation Buffer SoGLRenderAction :: setNumPasses(int num)

CGVR Graphics Korea University cgvr.korea.ac.kr 9 Rendering - Off-screen Rendering SoOffScreenRenderer Class Render an image into off-screen memory buffer  To generate image for a PostScript printer  To generate image for a Texture map SoOffScreenRenderer :: SetComponent(Components components)  LUMIANCE  LUMIANCE_TRANSPARENCY  RGB  RGB_TRANSPARENCY

CGVR Graphics Korea University cgvr.korea.ac.kr 10 Rendering - Source TEXTURE MAPPING SbBool generateTextureMap (SoNode *root, SoTexture2 *texture, short textureWidth, short textureHeight) { SbViewportRegion myViewport(textureWidth, textureHeight); // Render the scene SoOffscreenRenderer *myRenderer = new SoOffscreenRenderer(myViewport); myRenderer->setBackgroundColor(SbColor(0.3, 0.3, 0.3)); if (!myRenderer->render(root)) { delete myRenderer; return FALSE; } // Generate the texture texture->image.setValue(SbVec2s(textureWidth, textureHeight), SoOffscreenRenderer::RGB, myRenderer->getBuffer()); delete myRenderer; return TRUE; }

CGVR Graphics Korea University cgvr.korea.ac.kr 11 Rendering - Caching Saving of an operation Don’t need to traverse the scene graph every time SoSeparator node has 2 field for caching render caching:  renderCaching(SoSFEnum) bounding-box caching  boundingBoxCaching(SoSFEnum)  SoSFEnum => AUTO, ON, OFF How Caching Working Check a valid cache existence Ignore below scene graph and use cache(if C exists)

CGVR Graphics Korea University cgvr.korea.ac.kr 12 Calculating a Bounding Box Create an instance of the action sbViewportRegion vpReg; vpReg.setWindowSize(300, 200); SoGetBoundingBoxAction bboxAction(vpReg); Apply the Action bboxAction.apply(root); Obtain Result SoTransform *myTransform; myTransform->center = bboxAction.getCenter();

CGVR Graphics Korea University cgvr.korea.ac.kr 13 Accumulating a Transformation Matrix Create an instance of the action soGetMatrixAction mtxAction Apply the Action getMatrix() getInverse()

CGVR Graphics Korea University cgvr.korea.ac.kr 14 Writing to a File SoWriteAction class is used SoWriteAction myAction; Writing in binary with file pointer FILE *fp; myAction.getOutput()->setBinary(TRUE); myAction.getOutput()->setFilePointer(fp); myAction.apply(root); Writing in ASCII myAction.getOutput()->openFile(“file.iv”); myAciton.getOutput()->setBinary(FALSE); myAction.apply(root); myAction.getOutput()->closeFile();

CGVR Graphics Korea University cgvr.korea.ac.kr 15 Searching for a Node Example SoSearchAction mySearchAction mySearchAction.setType(SoLight::getClassTrypeId()); mySearchAction.setInterest (SoSearchAction::FIRST); mySearchAction.apply(root); If(mySearchAction.getPath() == NULL){ SoDirectionLight *myLight = new SoDirectionalLight; root->insertChild(myLight, 0); }

CGVR Graphics Korea University cgvr.korea.ac.kr 16 Picking –1 SoRayPickAction is used Find objects along a ray from the camera

CGVR Graphics Korea University cgvr.korea.ac.kr 17 Picking – 2 Specifying the Picking Ray SbViewportRegion viewport(400, 300); SbVec2s cursorPosition(250, 150); SoRayPickAction myPickAction(viewport); myPickAction.setRay(SbVec3f(0.0, 0.0, 0.0), //starting point SbVec3f(0.0, 0.0, -1.0)); //direction vector pickAction->apply(rootNode); Obtain result SoPath *pathToPickObject; Const SoPickPoint *myPickedPoint = pickAction.getPickedPoint(); If(myPickedPoint != NULL) pathToPickedobject = myPickedPoint->getPath();

CGVR Graphics Korea University cgvr.korea.ac.kr 18 Picking – 2 SoDetail Have an additional information about the pick Classes that store an SoDetail Class nameType of detail added SoCubeSoCubeDetail SoCylinderSoCylinderDetail SoPointSetSoPointDetail SoConeSoConeDetail

CGVR Graphics Korea University cgvr.korea.ac.kr 19 Using the Pick Action Writing the path to the Picked Object SbBool writePickedPath (SoNode *root, const SbViewportRegion &viewport, const SbVec2s &cursorPosition) { SoRayPickAction PickAction(viewport); PickAction.setPoint(cursorPosition); PickAction.setRadius(8.0); PickAction.apply(root); const SoPickedPoint *myPickedPoint = pickAction.getPickedPoint(); If(myPickedPoint == NULL) return FALSE; SoWriteAction myWriteAction; myWrtieAction.apply(myPickedPoint->getpath()); return TRUE; }

CGVR Graphics Korea University cgvr.korea.ac.kr 20 Calling Back to the Application SoCallbackAction Method which is called whenever a specified node encountered during the traversal Void printSpheres(SoNode *root) { SoCallbackAction myAction; myAction.addPreCallback(SoSphere::getClassTypeId(), printHeaderCallback, NULL); myAction.addTriangleCallback(SoSphere::getClassTypeId(), printTriangleCallback, NULL); myAction.apply(root); }