/** Generate elements
*/
static void makeElements( const SURF& surf,
std::vector<Element>& elements )
{
const unsigned n1 = surf.numIntervals1();
const unsigned n2 = surf.numIntervals2();
for ( unsigned j = 0; j < n2; j++ ) {
for ( unsigned i = 0; i < n1; i++ ) {
// following indices with boundary periodicity
const std::size_t iNext =
( i < n1 - 1 ? i+1 :
(surf.periodic1() ? 0 : i+1) );
const std::size_t jNext =
( j < n2 - 1 ? j+1 :
(surf.periodic2() ? 0 : j+1) );
// index shift to next line
const unsigned stride =
n1 + static_cast<unsigned>(not surf.periodic1());
// the four vertices of a quadrilateral
const std::size_t i1 = j * stride + i;
const std::size_t i2 = j * stride + iNext;
const std::size_t i4 = jNext * stride + i;
const std::size_t i3 = jNext * stride + iNext;
if ( surf.withTriangles() ) {
// generate two triangles
Element tri1, tri2;
tri1.push_back( i1 );
tri1.push_back( i2 );
tri1.push_back( i3 );
tri2.push_back( i3 );
tri2.push_back( i4 );
tri2.push_back( i1 );
elements.push_back( tri1 );
elements.push_back( tri2 );
}
else {
// generate a quadrilateral
Element quad;
quad.push_back( i1 );
quad.push_back( i2 );
quad.push_back( i3 );
quad.push_back( i4 );
elements.push_back( quad );
}
}
}
return;
}
/** Generate points
*/
static void makePoints( const SURF& surf,
std::vector<Point>& points )
{
const unsigned n1 =
surf.numIntervals1() + (surf.periodic1() ? 0 : 1 );
const unsigned n2 =
surf.numIntervals2() + (surf.periodic2() ? 0 : 1 );
for ( unsigned j = 0; j < n2; j++ ) {
for ( unsigned i = 0; i < n1; i++ ) {
points.push_back( surf.makePoint( i, j ) );
}
}
}
