// tesselates the contours in preparation for a 3D output;
// returns true if all was fine, false otherwise
bool VRML_LAYER::Tesselate( VRML_LAYER* holes, bool aHolesOnly )
{
if( !tess )
{
error = "Tesselate(): GLU tesselator was not initialized";
return false;
}
pholes = holes;
Fault = false;
if( aHolesOnly )
gluTessProperty( tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NEGATIVE );
else
gluTessProperty( tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_POSITIVE );
if( contours.size() < 1 || vertices.size() < 3 )
{
error = "Tesselate(): not enough vertices";
return false;
}
// finish the winding calculation on all vertices prior to setting 'fix'
if( !fix )
{
for( unsigned int i = 0; i < contours.size(); ++i )
{
if( contours[i]->size() < 3 )
continue;
VERTEX_3D* vp0 = vertices[ contours[i]->back() ];
VERTEX_3D* vp1 = vertices[ contours[i]->front() ];
areas[i] += ( vp1->x - vp0->x ) * ( vp1->y + vp0->y );
}
}
// prevent the addition of any further contours and contour vertices
fix = true;
// clear temporary internals which may have been used in a previous run
clearTmp();
// request an outline
gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_TRUE );
// adjust internal indices for extra points and holes
if( holes )
hidx = holes->GetSize();
else
hidx = 0;
eidx = idx + hidx;
if( aHolesOnly && ( checkNContours( true ) == 0 ) )
{
error = "tesselate(): no hole contours";
return false;
}
else if( !aHolesOnly && ( checkNContours( false ) == 0 ) )
{
error = "tesselate(): no solid contours";
return false;
}
// open the polygon
gluTessBeginPolygon( tess, this );
if( aHolesOnly )
{
pholes = NULL; // do not accept foreign holes
hidx = 0;
eidx = idx;
// add holes
pushVertices( true );
gluTessEndPolygon( tess );
if( Fault )
return false;
return true;
}
// add solid outlines
pushVertices( false );
// close the polygon
gluTessEndPolygon( tess );
if( Fault )
return false;
// if there are no outlines we cannot proceed
if( outline.empty() )
{
error = "tesselate(): no points in result";
return false;
}
// at this point we have a solid outline; add it to the tesselator
gluTessBeginPolygon( tess, this );
if( !pushOutline( NULL ) )
return false;
// add the holes contained by this object
pushVertices( true );
// import external holes (if any)
if( hidx && ( holes->Import( idx, tess ) < 0 ) )
{
std::ostringstream ostr;
ostr << "Tesselate():FAILED: " << holes->GetError();
error = ostr.str();
return false;
}
if( Fault )
return false;
// erase the previous outline data and vertex order
// but preserve the extra vertices
while( !outline.empty() )
{
delete outline.back();
outline.pop_back();
}
ordmap.clear();
ord = 0;
// go through the vertex lists and reset ephemeral parameters
for( unsigned int i = 0; i < vertices.size(); ++i )
{
vertices[i]->o = -1;
}
for( unsigned int i = 0; i < extra_verts.size(); ++i )
{
extra_verts[i]->o = -1;
}
// close the polygon; this creates the outline points
// and the point ordering list 'ordmap'
solid.clear();
gluTessEndPolygon( tess );
// repeat the last operation but request a tesselated surface
// rather than an outline; this creates the triangles list.
gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_FALSE );
gluTessBeginPolygon( tess, this );
if( !pushOutline( holes ) )
return false;
gluTessEndPolygon( tess );
if( Fault )
return false;
return true;
}
// tesselates the contours in preparation for a 3D output;
// returns true if all was fine, false otherwise
bool VRML_LAYER::Tesselate( VRML_LAYER* holes )
{
if( !tess )
{
error = "Tesselate(): GLU tesselator was not initialized";
return false;
}
pholes = holes;
Fault = false;
if( contours.size() < 1 || vertices.size() < 3 )
{
error = "Tesselate(): not enough vertices";
return false;
}
// finish the winding calculation on all vertices prior to setting 'fix'
if( !fix )
{
for( unsigned int i = 0; i < contours.size(); ++i )
{
if( contours[i]->size() < 3 )
continue;
VERTEX_3D* vp0 = vertices[ contours[i]->back() ];
VERTEX_3D* vp1 = vertices[ contours[i]->front() ];
areas[i] += ( vp1->x - vp0->x ) * ( vp1->y + vp0->y );
}
}
// prevent the addition of any further contours and contour vertices
fix = true;
// clear temporary internals which may have been used in a previous run
clearTmp();
// request an outline
gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_TRUE );
// adjust internal indices for extra points and holes
if( holes )
hidx = holes->GetSize();
else
hidx = 0;
eidx = idx + hidx;
// open the polygon
gluTessBeginPolygon( tess, this );
pushVertices( false );
// close the polygon
gluTessEndPolygon( tess );
if( Fault )
return false;
// push the (solid) outline to the tesselator
if( !pushOutline( holes ) )
return false;
// add the holes contained by this object
pushVertices( true );
// import external holes (if any)
if( hidx && ( holes->Import( idx, tess ) < 0 ) )
{
std::ostringstream ostr;
ostr << "Tesselate():FAILED: " << holes->GetError();
error = ostr.str();
return NULL;
}
if( Fault )
return false;
// erase the previous outline data and vertex order
// but preserve the extra vertices
for( int i = outline.size(); i > 0; --i )
{
delete outline.back();
outline.pop_back();
}
for( unsigned int i = ordmap.size(); i > 0; --i )
ordmap.pop_back();
// go through the vertex lists and reset ephemeral parameters
for( unsigned int i = 0; i < vertices.size(); ++i )
{
vertices[i]->o = -1;
}
for( unsigned int i = 0; i < extra_verts.size(); ++i )
{
extra_verts[i]->o = -1;
}
ord = 0;
// close the polygon; we now have all the data necessary for the tesselation
gluTessEndPolygon( tess );
// request a tesselated surface
gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_FALSE );
if( !pushOutline( holes ) )
return false;
gluTessEndPolygon( tess );
if( Fault )
return false;
return true;
}
