// SimplerConvexUmbrellaSdfAlgo.cpp: implementation of the SimplerConvexUmbrellaSdfAlgo class.
//
//////////////////////////////////////////////////////////////////////

#include "SimplerConvexUmbrellaSdfAlgo.h"
using namespace SDF;

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

SimplerConvexUmbrellaSdfAlgo::SimplerConvexUmbrellaSdfAlgo()
{

}

SimplerConvexUmbrellaSdfAlgo::~SimplerConvexUmbrellaSdfAlgo()
{

}

//--------------------------------
// x - the closest point on the surface
// p - the pt to classify
// tris - the tris that share that closest pt
//--------------------------------
SimplerConvexUmbrellaSdfAlgo::PointClass
SimplerConvexUmbrellaSdfAlgo::
classify_pt_by_umbrella_tris(const TriangleList &tris, const Point &x, const Point &p)
{
	//	We do this by going through every triangle, and calculating other triangles'
	//	relative positions to it.  There are three possible relative positions:
	//		COPLANAR - the two triangles are co-planar
	//		B_BEHIND_A - tri B is behind A - meaning its centroid is behind A's face plane
	//		B_INFRONT_A - ditto.
	//	For any triangle A, if there exists two triangles B1 B2 such that B1 is behind
	//	and B2 is in front, then A must NOT be a face on the convex umbrella.
	//	But if B1 and B2 do not exist, then all other triangles B are either coplanar,
	//	or ALL have relative position p - where p is either BEHIND or INFRONT.
	//	If p is BEHIND, we classify the point as outside.
	//	If p is INFRONT, we classify the point as inside.

	PointClass klass = DONT_KNOW;

	for(unsigned int i = 0; i < tris.size(); i++) {
		MeshTriangle *A = tris.at(i);

		// Relative position info for A
		int numBehind = 0;
		int numInFront = 0;

		//--------------------------------
		// Go through all other tris
		// and calcualte relative positions
		//--------------------------------
		for(unsigned int j = 0; j < tris.size(); j++ ) {
			if( j == i ) {
				continue;
			}
			MeshTriangle *B = tris.at(j);

			// Is this behind?
			RelativePosition relPos =
				calc_relative_position_of_umbrella_tris(*A, *B);

			if(relPos == COPLANAR) {
				// This doesn't help.
				// Ignore it.
			}
			else if(relPos == B_BEHIND_A) {
				numBehind++;
			}
			else if(relPos == B_INFRONT_A) {
				numInFront++;
			}
			else {
				// Weird..this shouldn't happen
				fprintf(stderr, "\n\n *** classify_pt_by_umbrella_tris: WE GOT RELPOS_DONT_KNOW for two tris.. \n\n");
			}
		}

		//--------------------------------
		// Now see - is A a face on the convex umbrella?
		//--------------------------------
		if(numBehind > 0 && numInFront > 0) {
			// Some were in front, some were behind.
			// This is definitely NOT on the convex umb
			// Keep seraching.
			continue;
		}
		else if(numBehind > 0 && numInFront == 0) {
			// All other tris were coplanar or behind!!
			// We can classify the point as outside!
			klass = EXTERIOR;

			// We're done.
			break;
		}
		else if(numInFront > 0 && numBehind == 0) {
			// All other tris were coplanar or IN FRONT of A!!
			// We can classify the point as inside.
			klass = INTERIOR;

			// We're done.
			break;
		}
		else {
			// All the faces are coplanar.
			// OK, just use any one of them to classify the point.
			// Let's use A.

				//--------------------------------
				// TODO - We should check that they all agree on the classification!
				//--------------------------------

			klass = this->classify_pt_by_single_best_triangle(*A, this->);

			// ADDED this line 2005-12-06
			break;
		}
	}

	return klass;
}