/**************************************************************************\ * * This file is part of the Coin 3D visualization library. * Copyright (C) 1998-2007 by Systems in Motion. All rights reserved. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * ("GPL") version 2 as published by the Free Software Foundation. * See the file LICENSE.GPL at the root directory of this source * distribution for additional information about the GNU GPL. * * For using Coin with software that can not be combined with the GNU * GPL, and for taking advantage of the additional benefits of our * support services, please contact Systems in Motion about acquiring * a Coin Professional Edition License. * * See http://www.coin3d.org/ for more information. * * Systems in Motion, Postboks 1283, Pirsenteret, 7462 Trondheim, NORWAY. * http://www.sim.no/ sales@sim.no coin-support@coin3d.org * \**************************************************************************/ #ifdef HAVE_CONFIG_H #include #endif // HAVE_CONFIG_H #ifdef HAVE_VRML97 /*! \class SoVRMLBillboard SoVRMLBillboard.h Inventor/VRMLnodes/SoVRMLBillboard.h \brief The SoVRMLBillboard class is used for rotating geometry towards the viewpoint. \ingroup VRMLnodes \WEB3DCOPYRIGHT \verbatim Billboard { eventIn MFNode addChildren eventIn MFNode removeChildren exposedField SFVec3f axisOfRotation 0 1 0 # (-inf, inf) exposedField MFNode children [] field SFVec3f bboxCenter 0 0 0 # (-inf, inf) field SFVec3f bboxSize -1 -1 -1 # (0, inf) or -1,-1,-1 } \endverbatim The Billboard node is a grouping node which modifies its coordinate system so that the Billboard node's local Z-axis turns to point at the viewer. The Billboard node has children which may be other children nodes. The axisOfRotation field specifies which axis to use to perform the rotation. This axis is defined in the local coordinate system. When the axisOfRotation field is not (0, 0, 0), the following steps describe how to rotate the billboard to face the viewer: \li a. Compute the vector from the Billboard node's origin to the viewer's position. This vector is called the billboard-to-viewer vector. \li b. Compute the plane defined by the axisOfRotation and the billboard-to-viewer vector. \li c. Rotate the local Z-axis of the billboard into the plane from b., pivoting around the axisOfRotation. When the axisOfRotation field is set to (0, 0, 0), the special case of viewer-alignment is indicated. In this case, the object rotates to keep the billboard's local Y-axis parallel with the Y-axis of the viewer. This special case is distinguished by setting the axisOfRotation to (0, 0, 0). The following steps describe how to align the billboard's Y-axis to the Y-axis of the viewer: \li d. Compute the billboard-to-viewer vector. \li e. Rotate the Z-axis of the billboard to be collinear with the billboard-to-viewer vector and pointing towards the viewer's position. \li f. Rotate the Y-axis of the billboard to be parallel and oriented in the same direction as the Y-axis of the viewer. If the axisOfRotation and the billboard-to-viewer line are coincident, the plane cannot be established and the resulting rotation of the billboard is undefined. For example, if the axisOfRotation is set to (0,1,0) (Y-axis) and the viewer flies over the billboard and peers directly down the Y-axis, the results are undefined. Multiple instances of Billboard nodes (DEF/USE) operate as expected: each instance rotates in its unique coordinate system to face the viewer. Subclause 4.6.5, Grouping and children nodes (), provides a description of the children, addChildren, and removeChildren fields and eventIns. The bboxCenter and bboxSize fields specify a bounding box that encloses the Billboard node's children. This is a hint that may be used for optimization purposes. The results are undefined if the specified bounding box is smaller than the actual bounding box of the children at any time. A default bboxSize value, (-1, -1, -1), implies that the bounding box is not specified and if needed shall be calculated by the browser. A description of the bboxCenter and bboxSize fields is contained in 4.6.4, Bounding boxes (), \ENDWEB3D The following example VRML scene is a simple illustration of how SoVRMLBillboard::axisOfRotation constrains rotation around the given vector: \verbatim #VRML V2.0 utf8 Transform { translation -2 0 0 children [ Billboard { children [ Box { } ] } ] } Transform { translation 2 0 0 children [ Billboard { axisOfRotation 0 1 0 children [ Box { } ] } ] } Transform { translation 0 -2 0 children [ Box { size 10 0.1 10 } ] } \endverbatim */ // ************************************************************************* /*! \var SoSFVec3f SoVRMLBillboard::axisOfRotation The axis of rotation for the geometry. */ /*! \var SoSFVec3f SoVRMLBillboard::bboxCenter The bounding box center hint. Default value is (0, 0, 0). */ /*! \var SoSFVec3f SoVRMLBillboard::bboxSize The bounding box size hint. Default value is (-1, -1, -1). */ // ************************************************************************* #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // ************************************************************************* SO_NODE_SOURCE(SoVRMLBillboard); // ************************************************************************* // Doc in parent void SoVRMLBillboard::initClass(void) { SO_NODE_INTERNAL_INIT_CLASS(SoVRMLBillboard, SO_VRML97_NODE_TYPE); } /*! Constructor. */ SoVRMLBillboard::SoVRMLBillboard(void) { SO_VRMLNODE_INTERNAL_CONSTRUCTOR(SoVRMLBillboard); SO_VRMLNODE_ADD_EXPOSED_FIELD(axisOfRotation, (0.0f, 0.0f, 0.0f)); SO_VRMLNODE_ADD_FIELD(bboxCenter, (0.0f, 0.0f, 0.0f)); SO_VRMLNODE_ADD_FIELD(bboxSize, (-1.0f, -1.0f, -1.0f)); } /*! Constructor. \a numchildren is the expected number of children. */ SoVRMLBillboard::SoVRMLBillboard(int numchildren) : inherited(numchildren) { } /*! Destructor. */ SoVRMLBillboard::~SoVRMLBillboard() { } // ************************************************************************* // Doc in parent void SoVRMLBillboard::doAction(SoAction * action) { SoState * state = action->getState(); state->push(); this->performRotation(state); SoGroup::doAction(action); state->pop(); } // Doc in parent void SoVRMLBillboard::callback(SoCallbackAction * action) { SoVRMLBillboard::doAction((SoAction*) action); } // Doc in parent void SoVRMLBillboard::GLRender(SoGLRenderAction * action) { switch (action->getCurPathCode()) { case SoAction::NO_PATH: case SoAction::BELOW_PATH: this->GLRenderBelowPath(action); break; case SoAction::OFF_PATH: // do nothing. Separator will reset state. break; case SoAction::IN_PATH: this->GLRenderInPath(action); break; } } // Doc in parent void SoVRMLBillboard::getBoundingBox(SoGetBoundingBoxAction * action) { SoState * state = action->getState(); state->push(); this->performRotation(state); SoGroup::getBoundingBox(action); state->pop(); } // Doc in parent void SoVRMLBillboard::getMatrix(SoGetMatrixAction * action) { // FIXME: hmmm, what should I do here. pederb, 2001-10-30 } // Doc in parent void SoVRMLBillboard::pick(SoPickAction * action) { SoVRMLBillboard::doAction((SoAction*) action); } // Doc in parent void SoVRMLBillboard::search(SoSearchAction * action) { SoNode::search(action); if (action->isFound()) return; SoGroup::doAction(action); } // Doc in parent void SoVRMLBillboard::GLRenderBelowPath(SoGLRenderAction * action) { SoState * state = action->getState(); // never cache this node SoCacheElement::invalidate(state); state->push(); this->performRotation(state); int n = this->getChildren()->getLength(); SoNode ** childarray = (SoNode**) this->getChildren()->getArrayPtr(); action->pushCurPath(); for (int i = 0; i < n && !action->hasTerminated(); i++) { action->popPushCurPath(i, childarray[i]); if (action->abortNow()) { // only cache if we do a full traversal break; } childarray[i]->GLRenderBelowPath(action); #if COIN_DEBUG // The GL error test is default disabled for this optimized // path. If you get a GL error reporting an error in the // Separator node, enable this code by setting the environment // variable COIN_GLERROR_DEBUGGING to "1" to see exactly which // node caused the error. static SbBool chkglerr = sogl_glerror_debugging(); if (chkglerr) { cc_string str; cc_string_construct(&str); const unsigned int errs = coin_catch_gl_errors(&str); if (errs > 0) { SoDebugError::post("SoVRMLBillboard::GLRenderBelowPath", "GL error: '%s', nodetype: %s", cc_string_get_text(&str), (*this->getChildren())[i]->getTypeId().getName().getString()); } cc_string_clean(&str); } #endif // COIN_DEBUG } action->popCurPath(); state->pop(); } // Doc in parent void SoVRMLBillboard::GLRenderInPath(SoGLRenderAction * action ) { int numindices; const int * indices; SoAction::PathCode pathcode = action->getPathCode(numindices, indices); if (pathcode == SoAction::IN_PATH) { SoState * state = action->getState(); SoCacheElement::invalidate(state); SoNode ** childarray = (SoNode**) this->getChildren()->getArrayPtr(); state->push(); this->performRotation(state); int childidx = 0; for (int i = 0; i < numindices; i++) { for (; childidx < indices[i] && !action->hasTerminated(); childidx++) { SoNode * offpath = childarray[childidx]; if (offpath->affectsState()) { action->pushCurPath(childidx, offpath); if (!action->abortNow()) { offpath->GLRenderOffPath(action); } action->popCurPath(pathcode); } } SoNode * inpath = childarray[childidx]; action->pushCurPath(childidx, inpath); if (!action->abortNow()) { inpath->GLRenderInPath(action); } action->popCurPath(pathcode); childidx++; } state->pop(); } else { // we got to the end of the path assert(action->getCurPathCode() == SoAction::BELOW_PATH); this->GLRenderBelowPath(action); } } // Doc in parent void SoVRMLBillboard::GLRenderOffPath(SoGLRenderAction * action) { // do nothing } // Doc in parent void SoVRMLBillboard::notify(SoNotList * list) { inherited::notify(list); } // // private method that appends the needed rotation to the state // void SoVRMLBillboard::performRotation(SoState * state) const { SbMatrix imm = SoModelMatrixElement::get(state).inverse(); const SbViewVolume & vv = SoViewVolumeElement::get(state); SbVec3f up, toviewer; imm.multDirMatrix(vv.getViewUp(), up); imm.multVecMatrix(vv.getProjectionPoint(), toviewer); if (toviewer.normalize() < FLT_EPSILON) { // we're not going to be able to calculate anything if the // projection point is in origo return; } SbVec3f rotaxis = this->axisOfRotation.getValue(); SbVec3f yaxis(0.0f, 1.0f, 0.0f); SbVec3f zaxis(0.0f, 0.0f, 1.0f); SbRotation rot = SbRotation::identity(); if (rotaxis == SbVec3f(0.0f, 0.0f, 0.0f)) { // 1. Compute the billboard-to-viewer vector. // 2. Rotate the Z-axis of the billboard to be collinear with the // billboard-to-viewer vector and pointing towards the viewer's position. // 3. Rotate the Y-axis of the billboard to be parallel and oriented in the // same direction as the Y-axis of the viewer. rot.setValue(zaxis, toviewer); rot.multVec(yaxis, yaxis); rot *= SbRotation(yaxis, up); } else { // 1. Compute the vector from the Billboard node's origin to the viewer's // position. This vector is called the billboard-to-viewer vector. // 2. Compute the plane defined by the axisOfRotation and the // billboard-to-viewer vector. // 3. Rotate the local Z-axis of the billboard into the plane from 2., // pivoting around the axisOfRotation. SbVec3f planenormal(rotaxis.cross(toviewer)); if (planenormal.normalize() > FLT_EPSILON) { // Calculate projection vector of local Z-axis to plane defined by // the axisOfRotation and the billboard-to-viewer vector and then // apply rotation around axisOfRotation that will rotate Z-axis to // this projection. SbVec3f vecinplane = zaxis - planenormal * planenormal[2]; (void) vecinplane.normalize(); if (vecinplane.dot(toviewer) < 0.0f) vecinplane = - vecinplane; float angle = (float) acos(SbClamp(zaxis.dot(vecinplane), -1.0f, 1.0f)); rot.setValue(rotaxis, planenormal[2] < 0.0f ? angle : - angle); } } SoModelMatrixElement::rotateBy(state, (SoNode*) this, rot); } #endif // HAVE_VRML97