void bezierSplit( const Bezier& b, Bezier* b0, Bezier* b1 ) {
Point p01 = midLine( b.p0, b.p1 );
Point p12 = midLine( b.p1, b.p2 );
Point p23 = midLine( b.p2, b.p3 );
Point p02 = midLine( p01, p12 );
Point p13 = midLine( p12, p23 );
Point p03 = midLine( p02, p13 );
b0->set( b.p0, p01, p02, p03 );
b1->set( p03, p13, p23, b.p3 );
}
vector<VertexObject*> DivideAndConquerFor3DCH::find2DConvexHull( list<VertexObject*> *pointSet )
{
vector<VertexObject*> upper;
vector<VertexObject*> lower;
list<VertexObject*>::iterator pointIter;
D3DXVECTOR2 midLine( pointSet->back()->v->x - pointSet->front()->v->x, pointSet->back()->v->y - pointSet->front()->v->y );
for( pointIter = pointSet->begin(); pointIter != pointSet->end(); pointIter++ )
{
D3DXVECTOR2 currentLine( (*pointIter)->v->x - pointSet->front()->v->x, (*pointIter)->v->y - pointSet->front()->v->y );
float crossProduct = midLine.x * currentLine.y - midLine.y * currentLine.x;
if( crossProduct > 0 || (*pointIter) == pointSet->front() || (*pointIter) == pointSet->back() )
{
upper.push_back( (*pointIter) );
}
}
list<VertexObject*>::reverse_iterator re_pointIter;
midLine = D3DXVECTOR2( pointSet->front()->v->x - pointSet->back()->v->x, pointSet->front()->v->y - pointSet->back()->v->y );
for( re_pointIter = pointSet->rbegin(); re_pointIter != pointSet->rend(); re_pointIter++ )
{
D3DXVECTOR2 currentLine( (*re_pointIter)->v->x - pointSet->back()->v->x, (*re_pointIter)->v->y - pointSet->back()->v->y );
float crossProduct = midLine.x * currentLine.y - midLine.y * currentLine.x;
if( crossProduct > 0 || (*re_pointIter) == pointSet->front() || (*re_pointIter) == pointSet->back() )
{
lower.push_back( (*re_pointIter) );
}
}
vector<VertexObject*> upperChain;
vector<VertexObject*> lowerChain;
upperChain.push_back( upper[ 0 ] );
upperChain.push_back( upper[ 1 ] );
for( int i = 2; i < upper.size(); i++ )
{
for( ; upperChain.size() >= 2 ; )
{
int upperChainSize = upperChain.size();
D3DXVECTOR2 currentLine( upper[ i ]->v->x - upperChain[ upperChainSize - 1 ]->v->x, upper[ i ]->v->y - upperChain[ upperChainSize - 1 ]->v->y );
D3DXVECTOR2 preLine( upperChain[ upperChainSize - 1 ]->v->x - upperChain[ upperChainSize - 2 ]->v->x, upperChain[ upperChainSize - 1 ]->v->y - upperChain[ upperChainSize - 2 ]->v->y );
float crossProduct = preLine.x * currentLine.y - preLine.y * currentLine.x;
if( crossProduct > 0 )
{
upperChain.pop_back();
}
else
{
break;
}
}
upperChain.push_back( upper[ i ] );
}
lowerChain.push_back( lower[ 0 ] );
lowerChain.push_back( lower[ 1 ] );
for( int i = 2; i < lower.size(); i++ )
{
for( ; lowerChain.size() >= 2 ; )
{
int lowerChainSize = lowerChain.size();
D3DXVECTOR2 currentLine( lower[ i ]->v->x - lowerChain[ lowerChainSize - 1 ]->v->x, lower[ i ]->v->y - lowerChain[ lowerChainSize - 1 ]->v->y );
D3DXVECTOR2 preLine( lowerChain[ lowerChainSize - 1 ]->v->x - lowerChain[ lowerChainSize - 2 ]->v->x, lowerChain[ lowerChainSize - 1 ]->v->y - lowerChain[ lowerChainSize - 2 ]->v->y );
float crossProduct = preLine.x * currentLine.y - preLine.y * currentLine.x;
if( crossProduct > 0 )
{
lowerChain.pop_back();
}
else
{
break;
}
}
lowerChain.push_back( lower[ i ] );
}
upperChain.pop_back();
lowerChain.pop_back();
for( int i = 0; i < lowerChain.size(); i++ )
{
upperChain.push_back( lowerChain[ i ] );
}
return upperChain;
}