C++ FEdge::center2d方法代码示例

void CulledOccluderSource::cullViewEdges(ViewMap& viewMap, bool extensiveFEdgeSearch)
{
	// Cull view edges by marking them as non-displayable.
	// This avoids the complications of trying to delete edges from the ViewMap.

	// Non-displayable view edges will be skipped over during visibility calculation.

	// View edges will be culled according to their position w.r.t. the viewport proscenium (viewport + 5% border,
	// or some such).

	// Get proscenium boundary for culling
	real viewProscenium[4];
	GridHelpers::getDefaultViewProscenium(viewProscenium);
	real prosceniumOrigin[2];
	prosceniumOrigin[0] = (viewProscenium[1] - viewProscenium[0]) / 2.0;
	prosceniumOrigin[1] = (viewProscenium[3] - viewProscenium[2]) / 2.0;
	if (G.debug & G_DEBUG_FREESTYLE) {
		cout << "Proscenium culling:" << endl;
		cout << "Proscenium: [" << viewProscenium[0] << ", " << viewProscenium[1] << ", " << viewProscenium[2] <<
		        ", " << viewProscenium[3] << "]"<< endl;
		cout << "Origin: [" << prosceniumOrigin[0] << ", " << prosceniumOrigin[1] << "]"<< endl;
	}

	// A separate occluder proscenium will also be maintained, starting out the same as the viewport proscenium, and
	// expanding as necessary so that it encompasses the center point of at least one feature edge in each
	// retained view edge.
	// The occluder proscenium will be used later to cull occluding triangles before they are inserted into the Grid.
	// The occluder proscenium starts out the same size as the view proscenium
	GridHelpers::getDefaultViewProscenium(occluderProscenium);

	// XXX Freestyle is inconsistent in its use of ViewMap::viewedges_container and vector<ViewEdge*>::iterator.
	// Probably all occurences of vector<ViewEdge*>::iterator should be replaced ViewMap::viewedges_container
	// throughout the code.
	// For each view edge
	ViewMap::viewedges_container::iterator ve, veend;

	for (ve = viewMap.ViewEdges().begin(), veend = viewMap.ViewEdges().end(); ve != veend; ve++) {
		// Overview:
		//    Search for a visible feature edge
		//    If none: mark view edge as non-displayable
		//    Otherwise:
		//        Find a feature edge with center point inside occluder proscenium.
		//        If none exists, find the feature edge with center point closest to viewport origin.
		//            Expand occluder proscenium to enclose center point.

		// For each feature edge, while bestOccluderTarget not found and view edge not visibile
		bool bestOccluderTargetFound = false;
		FEdge *bestOccluderTarget = NULL;
		real bestOccluderDistance = 0.0;
		FEdge *festart = (*ve)->fedgeA();
		FEdge *fe = festart;
		// All ViewEdges start culled
		(*ve)->setIsInImage(false);

		// For simple visibility calculation: mark a feature edge that is known to have a center point inside
		// the occluder proscenium. Cull all other feature edges.
		do {
			// All FEdges start culled
			fe->setIsInImage(false);

			// Look for the visible edge that can most easily be included in the occluder proscenium.
			if (!bestOccluderTargetFound) {
				// If center point is inside occluder proscenium,
				if (insideProscenium(occluderProscenium, fe->center2d())) {
					// Use this feature edge for visibility deterimination
					fe->setIsInImage(true);
					expandGridSpaceOccluderProscenium(fe);
					// Mark bestOccluderTarget as found
					bestOccluderTargetFound = true;
					bestOccluderTarget = fe;
				}
				else {
					real d = distance2D(fe->center2d(), prosceniumOrigin);
					// If center point is closer to viewport origin than current target
					if (bestOccluderTarget == NULL || d < bestOccluderDistance) {
						// Then store as bestOccluderTarget
						bestOccluderDistance = d;
						bestOccluderTarget = fe;
					}
				}
			}

			// If feature edge crosses the view proscenium
			if (!(*ve)->isInImage() && crossesProscenium(viewProscenium, fe)) {
				// Then the view edge will be included in the image
				(*ve)->setIsInImage(true);
			}
			fe = fe->nextEdge();
		} while (fe != NULL && fe != festart && !(bestOccluderTargetFound && (*ve)->isInImage()));

		// Either we have run out of FEdges, or we already have the one edge we need to determine visibility
		// Cull all remaining edges.
		while (fe != NULL && fe != festart) {
			fe->setIsInImage(false);
			fe = fe->nextEdge();
		}

		// If bestOccluderTarget was not found inside the occluder proscenium, 
		// we need to expand the occluder proscenium to include it.
		if ((*ve)->isInImage() && bestOccluderTarget != NULL && ! bestOccluderTargetFound) {
//.........这里部分代码省略.........