//calculate the cost of a ray-traced line
double CostmapModel::lineCost(int x0, int x1,
int y0, int y1){
double line_cost = 0.0;
double point_cost = -1.0;
for( LineIterator line( x0, y0, x1, y1 ); line.isValid(); line.advance() )
{
point_cost = pointCost( line.getX(), line.getY() ); //Score the current point
if(point_cost < 0)
return -1;
if(line_cost < point_cost)
line_cost = point_cost;
}
return line_cost;
}
QgsGraph* RgShortestPathWidget::getPath( QgsPoint& p1, QgsPoint& p2 )
{
if ( mFrontPointLineEdit->text().isNull() || mBackPointLineEdit->text().isNull() )
{
QMessageBox::critical( this, tr( "Point not selected" ), tr( "First, select start and stop points." ) );
return NULL;
}
QgsGraphBuilder builder(
mPlugin->iface()->mapCanvas()->mapRenderer()->destinationCrs(),
mPlugin->iface()->mapCanvas()->mapRenderer()->hasCrsTransformEnabled(),
mPlugin->topologyToleranceFactor() );
{
const QgsGraphDirector *director = mPlugin->director();
if ( director == NULL )
{
QMessageBox::critical( this, tr( "Plugin isn't configured" ), tr( "Plugin isn't configured!" ) );
return NULL;
}
connect( director, SIGNAL( buildProgress( int, int ) ), mPlugin->iface()->mainWindow(), SLOT( showProgress( int, int ) ) );
connect( director, SIGNAL( buildMessage( QString ) ), mPlugin->iface()->mainWindow(), SLOT( showStatusMessage( QString ) ) );
QVector< QgsPoint > points;
QVector< QgsPoint > tiedPoint;
points.push_back( mFrontPoint );
points.push_back( mBackPoint );
director->makeGraph( &builder, points, tiedPoint );
p1 = tiedPoint[ 0 ];
p2 = tiedPoint[ 1 ];
// not need
delete director;
}
if ( p1 == QgsPoint( 0.0, 0.0 ) )
{
QMessageBox::critical( this, tr( "Tie point failed" ), tr( "Start point doesn't tie to the road!" ) );
return NULL;
}
if ( p2 == QgsPoint( 0.0, 0.0 ) )
{
QMessageBox::critical( this, tr( "Tie point failed" ), tr( "Stop point doesn't tie to the road!" ) );
return NULL;
}
QgsGraph *graph = builder.graph();
QVector< int > pointIdx( 0, 0 );
QVector< double > pointCost( 0, 0.0 );
int startVertexIdx = graph->findVertex( p1 );
int criterionNum = 0;
if ( mCriterionName->currentIndex() > 0 )
criterionNum = 1;
QgsGraph* shortestpathTree = QgsGraphAnalyzer::shortestTree( graph, startVertexIdx, criterionNum );
delete graph;
if ( shortestpathTree->findVertex( p2 ) == -1 )
{
QMessageBox::critical( this, tr( "Path not found" ), tr( "Path not found" ) );
return NULL;
}
return shortestpathTree;
}
//calculate the cost of a ray-traced line
double CostmapModel::lineCost(int x0, int x1,
int y0, int y1){
//Bresenham Ray-Tracing
int deltax = abs(x1 - x0); // The difference between the x's
int deltay = abs(y1 - y0); // The difference between the y's
int x = x0; // Start x off at the first pixel
int y = y0; // Start y off at the first pixel
int xinc1, xinc2, yinc1, yinc2;
int den, num, numadd, numpixels;
double line_cost = 0.0;
double point_cost = -1.0;
if (x1 >= x0) // The x-values are increasing
{
xinc1 = 1;
xinc2 = 1;
}
else // The x-values are decreasing
{
xinc1 = -1;
xinc2 = -1;
}
if (y1 >= y0) // The y-values are increasing
{
yinc1 = 1;
yinc2 = 1;
}
else // The y-values are decreasing
{
yinc1 = -1;
yinc2 = -1;
}
if (deltax >= deltay) // There is at least one x-value for every y-value
{
xinc1 = 0; // Don't change the x when numerator >= denominator
yinc2 = 0; // Don't change the y for every iteration
den = deltax;
num = deltax / 2;
numadd = deltay;
numpixels = deltax; // There are more x-values than y-values
}
else // There is at least one y-value for every x-value
{
xinc2 = 0; // Don't change the x for every iteration
yinc1 = 0; // Don't change the y when numerator >= denominator
den = deltay;
num = deltay / 2;
numadd = deltax;
numpixels = deltay; // There are more y-values than x-values
}
for (int curpixel = 0; curpixel <= numpixels; curpixel++)
{
point_cost = pointCost(x, y); //Score the current point
if(point_cost < 0)
return -1;
if(line_cost < point_cost)
line_cost = point_cost;
num += numadd; // Increase the numerator by the top of the fraction
if (num >= den) // Check if numerator >= denominator
{
num -= den; // Calculate the new numerator value
x += xinc1; // Change the x as appropriate
y += yinc1; // Change the y as appropriate
}
x += xinc2; // Change the x as appropriate
y += yinc2; // Change the y as appropriate
}
return line_cost;
}
