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/****************************************************************************
Copyright (C) 2002-2007 Gilles Debunne (Gilles.Debunne@imag.fr)
This file is part of the QGLViewer library.
Version 2.2.6-3, released on August 28, 2007.
http://artis.imag.fr/Members/Gilles.Debunne/QGLViewer
libQGLViewer is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
libQGLViewer is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with libQGLViewer; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
#include "select.h"
#include <qmessagebox.h>
#include <math.h>
using namespace std;
static void drawSpiral(const bool specialColor = false)
{
const float nbSteps = 100.0;
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 = 0.5 - 0.3*ratio;
float r2 = 0.3 - 0.3*ratio;
float alt = ratio - 0.5;
const float nor = .5;
const float up = sqrt(1.0-nor*nor);
if (specialColor)
glColor3f(1.0-ratio, .8 , ratio/2.0);
else
glColor3f(1.0-ratio, 0.2, ratio);
glNormal3f(nor*c, nor*s, up);
glVertex3f(r2*c, r2*s, alt+0.05);
glVertex3f(r1*c, r1*s, alt);
}
glEnd();
}
void Viewer::drawWithNames()
{
// Draw spirals, pushing a name (id) for each of them
const int nb = 10;
for (int i=0; i<nb; ++i)
{
glPushMatrix();
glTranslatef(cos(2.0*i*M_PI/nb), sin(2.0*i*M_PI/nb), 0.);
glPushName(i);
drawSpiral();
glPopName();
glPopMatrix();
}
}
void Viewer::postSelection(const QPoint& point)
{
// Compute orig and dir, used to draw a representation of the intersecting line
camera()->convertClickToLine(point, orig, dir);
// Find the selectedPoint coordinates, using camera()->pointUnderPixel().
bool found;
selectedPoint = camera()->pointUnderPixel(point, found);
selectedPoint -= 0.01*dir; // Small offset to make point clearly visible.
// Note that "found" is different from (selectedObjectId()>=0) because of the size of the select region.
if (selectedName() == -1)
QMessageBox::information(this, "No selection",
"No object selected under pixel " + QString::number(point.x()) + "," + QString::number(point.y()));
else
QMessageBox::information(this, "Selection",
"Spiral number " + QString::number(selectedName()) + " selected under pixel " +
QString::number(point.x()) + "," + QString::number(point.y()));
}
void Viewer::init()
{
restoreStateFromFile();
glLineWidth(3.0);
glPointSize(10.0);
help();
}
void Viewer::draw()
{
// Draw ten spirals
const int nb = 10;
for (int i=0; i<nb; ++i)
{
glPushMatrix();
glTranslatef(cos(2.0*i*M_PI/nb), sin(2.0*i*M_PI/nb), 0.0);
drawSpiral(i == selectedName());
glPopMatrix();
}
// Draw the intersection line
glBegin(GL_LINES);
glVertex3fv(orig);
glVertex3fv(orig + 100.0*dir);
glEnd();
// Draw (approximated) intersection point on selected object
if (selectedName() >= 0)
{
glColor3f(0.9, 0.2, 0.1);
glBegin(GL_POINTS);
glVertex3fv(selectedPoint);
glEnd();
}
}
QString Viewer::helpString() const
{
QString text("<h2>S e l e c t</h2>");
text += "Left click while pressing the <b>Shift</b> key to select an object of the scene.<br><br>";
text += "A line is drawn between the selected point and the camera selection position. ";
text += "using <i>convertClickToLine()</i>, a useful function for analytical intersections.<br><br>";
text += "To add object selection in your viewer, all you need to do is to define the <i>drawWithNames</i> function. ";
text += "It gives a name to each selectable object and selection is then performed using the OpenGL <i>GL_SELECT</i> render mode.<br><br>";
text += "Feel free to cut and paste this implementation in your own applications.";
return text;
}
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