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Constraints can limit the translation and/or rotation of a (Manipulated)Frame.
Try the different possible constraints using the T (translate) and R (rotate) keys. G and D change the constraint directions. Press Space to change the coordinate system (World, Camera or Local) which defines the constraint directions.
Press the Control key while moving the mouse to move the camera.
#include <QGLViewer/qglviewer.h> class Viewer : public QGLViewer { protected: virtual void init(); virtual void draw(); virtual QString helpString() const; virtual void keyPressEvent(QKeyEvent *); void displayText(); void displayType(const qglviewer::AxisPlaneConstraint::Type type, const int x, const int y, const char c); void displayDir(const unsigned short dir, const int x, const int y, const char c); private: int transDir; int rotDir; qglviewer::ManipulatedFrame* frame; void changeConstraint(); qglviewer::AxisPlaneConstraint* constraints[3]; unsigned short activeConstraint; };
#include "constrainedFrame.h" using namespace qglviewer; using namespace std; static AxisPlaneConstraint::Type nextTranslationConstraintType(const AxisPlaneConstraint::Type& type) { switch (type) { case AxisPlaneConstraint::FREE : return AxisPlaneConstraint::PLANE; break; case AxisPlaneConstraint::PLANE : return AxisPlaneConstraint::AXIS; break; case AxisPlaneConstraint::AXIS : return AxisPlaneConstraint::FORBIDDEN; break; case AxisPlaneConstraint::FORBIDDEN : return AxisPlaneConstraint::FREE; break; default : return AxisPlaneConstraint::FREE; } } static AxisPlaneConstraint::Type nextRotationConstraintType(const AxisPlaneConstraint::Type& type) { switch (type) { case AxisPlaneConstraint::FREE : return AxisPlaneConstraint::AXIS; break; case AxisPlaneConstraint::PLANE : return AxisPlaneConstraint::FREE; break; case AxisPlaneConstraint::AXIS : return AxisPlaneConstraint::FORBIDDEN; break; case AxisPlaneConstraint::FORBIDDEN : return AxisPlaneConstraint::FREE; break; default : return AxisPlaneConstraint::FREE; } } void Viewer::changeConstraint() { unsigned short previous = activeConstraint; activeConstraint = (activeConstraint+1)%3; constraints[activeConstraint]->setTranslationConstraintType(constraints[previous]->translationConstraintType()); constraints[activeConstraint]->setTranslationConstraintDir (constraints[previous]->translationConstraintDir()); constraints[activeConstraint]->setRotationConstraintType (constraints[previous]->rotationConstraintType()); constraints[activeConstraint]->setRotationConstraintDir (constraints[previous]->rotationConstraintDir()); frame->setConstraint(constraints[activeConstraint]); } void Viewer::init() { constraints[0] = new LocalConstraint(); constraints[1] = new WorldConstraint(); constraints[2] = new CameraConstraint(camera()); transDir = 0; // X direction rotDir = 0; // X direction activeConstraint = 0; frame = new ManipulatedFrame(); setManipulatedFrame(frame); frame->setConstraint(constraints[activeConstraint]); // Preserve CAMERA bindings, see setMouseStateKey documentation. setMouseStateKey(QGLViewer::CAMERA, Qt::AltButton); // The frames can be move without any key pressed setMouseStateKey(QGLViewer::FRAME, Qt::NoButton); // The camera can always be moved with the Control key. setMouseStateKey(QGLViewer::CAMERA, Qt::ControlButton); setDrawAxis(); restoreFromFile(); help(); } void Viewer::draw() { glMultMatrixd(frame->matrix()); drawAxis(0.4); const float scale = 0.3; glScalef(scale, scale, scale); const float nbSteps = 500.0; glBegin(GL_QUAD_STRIP); for (float i=0; i<nbSteps; ++i) { float ratio = i/nbSteps; float angle = 21.0*ratio; float c = cos(angle); float s = sin(angle); float r1 = 1.0 - 0.8*ratio; float r2 = 0.8 - 0.8*ratio; float alt = ratio - 0.5; const float nor = .5; const float up = sqrt(1.0-nor*nor); glColor3f(1-ratio, .2 , ratio); glNormal3f(nor*c*scale, up*scale, nor*s*scale); glVertex3f(r1*c, alt, r1*s); glVertex3f(r2*c, alt+0.05, r2*s); } glEnd(); displayText(); } void Viewer::keyPressEvent(QKeyEvent *e) { switch (e->key()) { case Qt::Key_G : transDir = (transDir+1)%3; break; case Qt::Key_D : rotDir = (rotDir+1)%3; break; case Qt::Key_Space: changeConstraint(); break; case Qt::Key_T : constraints[activeConstraint]->setTranslationConstraintType(nextTranslationConstraintType(constraints[activeConstraint]->translationConstraintType())); break; case Qt::Key_R : constraints[activeConstraint]->setRotationConstraintType(nextRotationConstraintType(constraints[activeConstraint]->rotationConstraintType())); break; default: QGLViewer::keyPressEvent(e); } Vec dir(0.0,0.0,0.0); dir[transDir] = 1.0; constraints[activeConstraint]->setTranslationConstraintDir(dir); dir = Vec(0.0,0.0,0.0); dir[rotDir] = 1.0; constraints[activeConstraint]->setRotationConstraintDir(dir); updateGL(); } void Viewer::displayType(const AxisPlaneConstraint::Type type, const int x, const int y, const char c) { char text[12]; switch (type) { case AxisPlaneConstraint::FREE: sprintf(text, "FREE (%c)", c); break; case AxisPlaneConstraint::PLANE: sprintf(text, "PLANE (%c)", c); break; case AxisPlaneConstraint::AXIS: sprintf(text, "AXIS (%c)", c); break; case AxisPlaneConstraint::FORBIDDEN: sprintf(text, "FORBIDDEN (%c)", c); break; } drawText(x, y, text); } void Viewer::displayDir(const unsigned short dir, const int x, const int y, const char c) { char text[6]; switch (dir) { case 0: sprintf(text, "X (%c)", c); break; case 1: sprintf(text, "Y (%c)", c); break; case 2: sprintf(text, "Z (%c)", c); break; } drawText(x, y, text); } void Viewer::displayText() { glColor3fv(foregroundColor().address()); glDisable(GL_LIGHTING); drawText(10, height()-30, "TRANSLATION :"); displayDir(transDir, 190, height()-30, 'G'); displayType(constraints[activeConstraint]->translationConstraintType(), 10, height()-60, 'T'); drawText(width()-220,height()-30, "ROTATION"); displayDir(rotDir, width()-100, height()-30, 'D'); displayType(constraints[activeConstraint]->rotationConstraintType(), width()-220, height()-60, 'R'); switch (activeConstraint) { case 0 : drawText(20,20, "Constraint direction defined w/r to LOCAL (SPACE)"); break; case 1 : drawText(20,20, "Constraint direction defined w/r to WORLD (SPACE)"); break; case 2 : drawText(20,20, "Constraint direction defined w/r to CAMERA (SPACE)"); break; } } QString Viewer::helpString() const { QString text("<h2>C o n s t r a i n e d F r a m e</h2>"); text += "A manipulated frame can be constrained in its displacement.<br>"; text += "Try the different translation (press <b>G</b> and <b>T</b>) and rotation "; text += "(<b>D</b> and <b>R</b>) constraints while moving the frame with the mouse.<br>"; text += "The constraints can be defined with respect to various coordinates"; text += "systems : press <b>Space</b> to switch.<br>"; text += "Press the <b>Control</b> key while moving the mouse to move the camera.<br>"; text += "You can easily define your own constraints to create a specific frame behavior."; return text; }
#include "constrainedFrame.h" #include <qapplication.h> int main(int argc, char** argv) { // Read command lines arguments. QApplication application(argc,argv); // Instantiate the viewer. Viewer v; // Make the viewer window visible on screen. v.show(); // Set the viewer as the application main widget. application.setMainWidget(&v); // Run main loop. return application.exec(); }
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