qtbase-opensource-src/examples/opengl/legacy/shared/qtlogo.cpp

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#include "qtlogo.h"
#include <QGLWidget>
#include <QMatrix4x4>
#include <QVector3D>
#include <QOpenGLFunctions_1_1>
#include <qmath.h>
static const qreal tee_height = 0.311126;
static const qreal cross_width = 0.25;
static const qreal bar_thickness = 0.113137;
static const qreal logo_depth = 0.10;
//! [0]
struct Geometry
{
QVector<GLushort> faces;
QVector<QVector3D> vertices;
QVector<QVector3D> normals;
void appendSmooth(const QVector3D &a, const QVector3D &n, int from);
void appendFaceted(const QVector3D &a, const QVector3D &n);
void finalize();
void loadArrays(QOpenGLFunctions_1_1 *functions) const;
};
//! [0]
//! [1]
class Patch
{
public:
enum Smoothing { Faceted, Smooth };
Patch(Geometry *);
void setSmoothing(Smoothing s) { sm = s; }
void translate(const QVector3D &t);
void rotate(qreal deg, QVector3D axis);
void draw(QOpenGLFunctions_1_1 *functions) const;
void addTri(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &n);
void addQuad(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &d);
GLushort start;
GLushort count;
GLushort initv;
GLfloat faceColor[4];
QMatrix4x4 mat;
Smoothing sm;
Geometry *geom;
};
//! [1]
static inline void qSetColor(float colorVec[], QColor c)
{
colorVec[0] = c.redF();
colorVec[1] = c.greenF();
colorVec[2] = c.blueF();
colorVec[3] = c.alphaF();
}
void Geometry::loadArrays(QOpenGLFunctions_1_1 *functions) const
{
functions->glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
functions->glNormalPointer(GL_FLOAT, 0, normals.constData());
}
void Geometry::finalize()
{
// TODO: add vertex buffer uploading here
// Finish smoothing normals by ensuring accumulated normals are returned
// to length 1.0.
for (int i = 0; i < normals.count(); ++i)
normals[i].normalize();
}
void Geometry::appendSmooth(const QVector3D &a, const QVector3D &n, int from)
{
// Smooth normals are achieved by averaging the normals for faces meeting
// at a point. First find the point in geometry already generated
// (working backwards, since most often the points shared are between faces
// recently added).
int v = vertices.count() - 1;
for ( ; v >= from; --v)
if (qFuzzyCompare(vertices[v], a))
break;
if (v < from) {
// The vertex was not found so add it as a new one, and initialize
// its corresponding normal
v = vertices.count();
vertices.append(a);
normals.append(n);
} else {
// Vert found, accumulate normals into corresponding normal slot.
// Must call finalize once finished accumulating normals
normals[v] += n;
}
// In both cases (found or not) reference the vertex via its index
faces.append(v);
}
void Geometry::appendFaceted(const QVector3D &a, const QVector3D &n)
{
// Faceted normals are achieved by duplicating the vertex for every
// normal, so that faces meeting at a vertex get a sharp edge.
int v = vertices.count();
vertices.append(a);
normals.append(n);
faces.append(v);
}
Patch::Patch(Geometry *g)
: start(g->faces.count())
, count(0)
, initv(g->vertices.count())
, sm(Patch::Smooth)
, geom(g)
{
qSetColor(faceColor, QColor(Qt::darkGray));
}
void Patch::rotate(qreal deg, QVector3D axis)
{
mat.rotate(deg, axis);
}
void Patch::translate(const QVector3D &t)
{
mat.translate(t);
}
//! [2]
void Patch::draw(QOpenGLFunctions_1_1 *functions) const
{
functions->glPushMatrix();
functions->glMultMatrixf(mat.constData());
functions->glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, faceColor);
const GLushort *indices = geom->faces.constData();
functions->glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_SHORT, indices + start);
functions->glPopMatrix();
}
//! [2]
void Patch::addTri(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &n)
{
QVector3D norm = n.isNull() ? QVector3D::normal(a, b, c) : n;
if (sm == Smooth) {
geom->appendSmooth(a, norm, initv);
geom->appendSmooth(b, norm, initv);
geom->appendSmooth(c, norm, initv);
} else {
geom->appendFaceted(a, norm);
geom->appendFaceted(b, norm);
geom->appendFaceted(c, norm);
}
count += 3;
}
void Patch::addQuad(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &d)
{
QVector3D norm = QVector3D::normal(a, b, c);
if (sm == Smooth) {
addTri(a, b, c, norm);
addTri(a, c, d, norm);
} else {
// If faceted share the two common vertices
addTri(a, b, c, norm);
int k = geom->vertices.count();
geom->appendSmooth(a, norm, k);
geom->appendSmooth(c, norm, k);
geom->appendFaceted(d, norm);
count += 3;
}
}
static inline QVector<QVector3D> extrude(const QVector<QVector3D> &vertices, qreal depth)
{
QVector<QVector3D> extr = vertices;
for (int v = 0; v < extr.count(); ++v)
extr[v].setZ(extr[v].z() - depth);
return extr;
}
class Rectoid
{
public:
void translate(const QVector3D &t)
{
for (int i = 0; i < parts.count(); ++i)
parts[i]->translate(t);
}
void rotate(qreal deg, QVector3D axis)
{
for (int i = 0; i < parts.count(); ++i)
parts[i]->rotate(deg, axis);
}
// No special Rectoid destructor - the parts are fetched out of this member
// variable, and destroyed by the new owner
QList<Patch *> parts;
};
class RectPrism : public Rectoid
{
public:
RectPrism(Geometry *g, qreal width, qreal height, qreal depth);
};
RectPrism::RectPrism(Geometry *g, qreal width, qreal height, qreal depth)
{
enum { bl, br, tr, tl };
Patch *fb = new Patch(g);
fb->setSmoothing(Patch::Faceted);
// front face
QVector<QVector3D> r(4);
r[br].setX(width);
r[tr].setX(width);
r[tr].setY(height);
r[tl].setY(height);
QVector3D adjToCenter(-width / 2.0, -height / 2.0, depth / 2.0);
for (int i = 0; i < 4; ++i)
r[i] += adjToCenter;
fb->addQuad(r[bl], r[br], r[tr], r[tl]);
// back face
QVector<QVector3D> s = extrude(r, depth);
fb->addQuad(s[tl], s[tr], s[br], s[bl]);
// side faces
Patch *sides = new Patch(g);
sides->setSmoothing(Patch::Faceted);
sides->addQuad(s[bl], s[br], r[br], r[bl]);
sides->addQuad(s[br], s[tr], r[tr], r[br]);
sides->addQuad(s[tr], s[tl], r[tl], r[tr]);
sides->addQuad(s[tl], s[bl], r[bl], r[tl]);
parts << fb << sides;
}
class RectTorus : public Rectoid
{
public:
RectTorus(Geometry *g, qreal iRad, qreal oRad, qreal depth, int numSectors);
};
RectTorus::RectTorus(Geometry *g, qreal iRad, qreal oRad, qreal depth, int k)
{
QVector<QVector3D> inside;
QVector<QVector3D> outside;
for (int i = 0; i < k; ++i) {
qreal angle = (i * 2 * M_PI) / k;
inside << QVector3D(iRad * qSin(angle), iRad * qCos(angle), depth / 2.0);
outside << QVector3D(oRad * qSin(angle), oRad * qCos(angle), depth / 2.0);
}
inside << QVector3D(0.0, iRad, 0.0);
outside << QVector3D(0.0, oRad, 0.0);
QVector<QVector3D> in_back = extrude(inside, depth);
QVector<QVector3D> out_back = extrude(outside, depth);
// Create front, back and sides as separate patches so that smooth normals
// are generated for the curving sides, but a faceted edge is created between
// sides and front/back
Patch *front = new Patch(g);
for (int i = 0; i < k; ++i)
front->addQuad(outside[i], inside[i],
inside[(i + 1) % k], outside[(i + 1) % k]);
Patch *back = new Patch(g);
for (int i = 0; i < k; ++i)
back->addQuad(in_back[i], out_back[i],
out_back[(i + 1) % k], in_back[(i + 1) % k]);
Patch *is = new Patch(g);
for (int i = 0; i < k; ++i)
is->addQuad(in_back[i], in_back[(i + 1) % k],
inside[(i + 1) % k], inside[i]);
Patch *os = new Patch(g);
for (int i = 0; i < k; ++i)
os->addQuad(out_back[(i + 1) % k], out_back[i],
outside[i], outside[(i + 1) % k]);
parts << front << back << is << os;
}
QtLogo::QtLogo(QObject *parent, int divisions, qreal scale)
: QObject(parent)
, geom(new Geometry())
{
buildGeometry(divisions, scale);
}
QtLogo::~QtLogo()
{
qDeleteAll(parts);
delete geom;
}
void QtLogo::setColor(QColor c)
{
for (int i = 0; i < parts.count(); ++i)
qSetColor(parts[i]->faceColor, c);
}
//! [3]
void QtLogo::buildGeometry(int divisions, qreal scale)
{
qreal cw = cross_width * scale;
qreal bt = bar_thickness * scale;
qreal ld = logo_depth * scale;
qreal th = tee_height *scale;
RectPrism cross(geom, cw, bt, ld);
RectPrism stem(geom, bt, th, ld);
QVector3D z(0.0, 0.0, 1.0);
cross.rotate(45.0, z);
stem.rotate(45.0, z);
qreal stem_downshift = (th + bt) / 2.0;
stem.translate(QVector3D(0.0, -stem_downshift, 0.0));
RectTorus body(geom, 0.20, 0.30, 0.1, divisions);
parts << stem.parts << cross.parts << body.parts;
geom->finalize();
}
//! [3]
//! [4]
void QtLogo::draw(QOpenGLFunctions_1_1 *functions) const
{
geom->loadArrays(functions);
functions->glEnableClientState(GL_VERTEX_ARRAY);
functions->glEnableClientState(GL_NORMAL_ARRAY);
for (int i = 0; i < parts.count(); ++i)
parts[i]->draw(functions);
functions->glDisableClientState(GL_VERTEX_ARRAY);
functions->glDisableClientState(GL_NORMAL_ARRAY);
}
//! [4]