cube.cpp Example File
opengl/pbuffers/cube.cpp

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 #include "cube.h"
 #include "glwidget.h"

 #include <QtGui/QImage>
 #include <QtCore/QPropertyAnimation>

 static const qreal FACE_SIZE = 0.4;

 static const qreal speeds[] = { 1.8f, 2.4f, 3.6f };
 static const qreal amplitudes[] = { 2.0f, 2.5f, 3.0f };

 static inline void qSetColor(float colorVec[], QColor c)
 {
     colorVec[0] = c.redF();
     colorVec[1] = c.greenF();
     colorVec[2] = c.blueF();
     colorVec[3] = c.alphaF();
 }

 int Geometry::append(const QVector3D &a, const QVector3D &n, const QVector2D &t)
 {
     int v = vertices.count();
     vertices.append(a);
     normals.append(n);
     texCoords.append(t);
     faces.append(v);
     colors.append(QVector4D(0.6f, 0.6f, 0.6f, 1.0f));
     return v;
 }

 void Geometry::addQuad(const QVector3D &a, const QVector3D &b,
                            const QVector3D &c, const QVector3D &d,
                            const QVector<QVector2D> &tex)
 {
     QVector3D norm = QVector3D::normal(a, b, c);
     // append first triangle
     int aref = append(a, norm, tex[0]);
     append(b, norm, tex[1]);
     int cref = append(c, norm, tex[2]);
     // append second triangle
     faces.append(aref);
     faces.append(cref);
     append(d, norm, tex[3]);
 }

 void Geometry::loadArrays() const
 {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glEnableClientState(GL_COLOR_ARRAY);
     glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
     glNormalPointer(GL_FLOAT, 0, normals.constData());
     glTexCoordPointer(2, GL_FLOAT, 0, texCoords.constData());
     glColorPointer(4, GL_FLOAT, 0, colors.constData());
 }

 void Geometry::setColors(int start, GLfloat colorArray[4][4])
 {
     int off = faces[start];
     for (int i = 0; i < 4; ++i)
         colors[i + off] = QVector4D(colorArray[i][0],
                                       colorArray[i][1],
                                       colorArray[i][2],
                                       colorArray[i][3]);
 }

 Tile::Tile(const QVector3D &loc)
     : location(loc)
     , start(0)
     , count(0)
     , useFlatColor(false)
     , geom(0)
 {
     qSetColor(faceColor, QColor(Qt::darkGray));
 }

 void Tile::setColors(GLfloat colorArray[4][4])
 {
     useFlatColor = true;
     geom->setColors(start, colorArray);
 }

 static inline void qMultMatrix(const QMatrix4x4 &mat)
 {
     if (sizeof(qreal) == sizeof(GLfloat))
         glMultMatrixf((GLfloat*)mat.constData());
 #ifndef QT_OPENGL_ES
     else if (sizeof(qreal) == sizeof(GLdouble))
         glMultMatrixd((GLdouble*)mat.constData());
 #endif
     else
     {
         GLfloat fmat[16];
         qreal const *r = mat.constData();
         for (int i = 0; i < 16; ++i)
             fmat[i] = r[i];
         glMultMatrixf(fmat);
     }
 }

 void Tile::draw() const
 {
     QMatrix4x4 mat;
     mat.translate(location);
     mat.rotate(orientation);
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     qMultMatrix(mat);
     glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, faceColor);
     glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_SHORT, geom->indices() + start);
     glPopMatrix();
 }

 TileBuilder::TileBuilder(Geometry *g, qreal depth, qreal size)
     : verts(4)
     , tex(4)
     , start(g->count())
     , count(0)
     , geom(g)
 {
     // front face - make a square with bottom-left at origin
     verts[br].setX(size);
     verts[tr].setX(size);
     verts[tr].setY(size);
     verts[tl].setY(size);

     // these vert numbers are good for the tex-coords
     for (int i = 0; i < 4; ++i)
         tex[i] = verts[i].toVector2D();

     // now move verts half cube width across so cube is centered on origin
     for (int i = 0; i < 4; ++i)
         verts[i] -= QVector3D(size / 2.0f, size / 2.0f, -depth);

     // add the front face
     g->addQuad(verts[bl], verts[br], verts[tr], verts[tl], tex);

     count = g->count() - start;
 }

 void TileBuilder::initialize(Tile *tile) const
 {
     tile->start = start;
     tile->count = count;
     tile->geom = geom;
     qSetColor(tile->faceColor, color);
 }

 Tile *TileBuilder::newTile(const QVector3D &loc) const
 {
     Tile *tile = new Tile(loc);
     initialize(tile);
     return tile;
 }

 Cube::Cube(const QVector3D &loc)
     : Tile(loc)
     , rot(0.0f)
     , r(0), a(0)
 {
 }

 Cube::~Cube()
 {
 }

 void Cube::setAltitude(qreal a)
 {
     if (location.y() != a)
     {
         location.setY(a);
         emit changed();
     }
 }

 void Cube::setRange(qreal r)
 {
     if (location.x() != r)
     {
         location.setX(r);
         emit changed();
     }
 }

 void Cube::setRotation(qreal r)
 {
     if (r != rot)
     {
         orientation = QQuaternion::fromAxisAndAngle(QVector3D(1.0f, 1.0f, 1.0f), r);
         emit changed();
     }
 }

 void Cube::removeBounce()
 {
     delete a;
     a = 0;
     delete r;
     r = 0;
 }

 void Cube::startAnimation()
 {
     if (r)
     {
         r->start();
         r->setCurrentTime(startx);
     }
     if (a)
         a->start();
     if (rtn)
         rtn->start();
 }

 void Cube::setAnimationPaused(bool paused)
 {
     if (paused)
     {
         if (r)
             r->pause();
         if (a)
             a->pause();
         if (rtn)
             rtn->pause();
     }
     else
     {
         if (r)
             r->resume();
         if (a)
             a->resume();
         if (rtn)
             rtn->resume();
     }
 }

 CubeBuilder::CubeBuilder(Geometry *g, qreal depth, qreal size)
     : TileBuilder(g, depth)
     , ix(0)
 {
     for (int i = 0; i < 4; ++i)
         verts[i].setZ(size / 2.0f);
     // back face - "extrude" verts down
     QVector<QVector3D> back(verts);
     for (int i = 0; i < 4; ++i)
         back[i].setZ(-size / 2.0f);

     // add the back face
     g->addQuad(back[br], back[bl], back[tl], back[tr], tex);

     // add the sides
     g->addQuad(back[bl], back[br], verts[br], verts[bl], tex);
     g->addQuad(back[br], back[tr], verts[tr], verts[br], tex);
     g->addQuad(back[tr], back[tl], verts[tl], verts[tr], tex);
     g->addQuad(back[tl], back[bl], verts[bl], verts[tl], tex);

     count = g->count() - start;
 }

 Cube *CubeBuilder::newCube(const QVector3D &loc) const
 {
     Cube *c = new Cube(loc);
     initialize(c);
     qreal d = 4000.0f;
     qreal d3 = d / 3.0f;
     // Animate movement from left to right
     c->r = new QPropertyAnimation(c, "range");
     c->r->setStartValue(-1.3f);
     c->r->setEndValue(1.3f);
     c->startx = ix * d3 * 3.0f;
     c->r->setDuration(d * 4.0f);
     c->r->setLoopCount(-1);
     c->r->setEasingCurve(QEasingCurve(QEasingCurve::CosineCurve));
     // Animate movement from bottom to top
     c->a = new QPropertyAnimation(c, "altitude");
     c->a->setEndValue(loc.y());
     c->a->setStartValue(loc.y() + amplitudes[ix]);
     c->a->setDuration(d / speeds[ix]);
     c->a->setLoopCount(-1);
     c->a->setEasingCurve(QEasingCurve(QEasingCurve::CosineCurve));
     // Animate rotation
     c->rtn = new QPropertyAnimation(c, "rotation");
     c->rtn->setStartValue(c->rot);
     c->rtn->setEndValue(359.0f);
     c->rtn->setDuration(d * 2.0f);
     c->rtn->setLoopCount(-1);
     c->rtn->setDuration(d / 2);
     ix = (ix + 1) % 3;
     return c;
 }