/*************************************************************************/
/*	File : CollisionManager.cpp										 */
/*																		 */	
/*************************************************************************/
#include "CKAll.h"
#include "CollisionManager.h"

//{secret}
int 
CollisionManager::GetNearestFace(CK3dEntity* ent1,CK3dEntity* ent2)
{
	float d2,d2min=10000000.0f;
	int facemin=0;

	VxVector pos,lpos;
	VxVector* p0;
	VxVector* p1;
	VxVector* p2;
	ent2->GetBaryCenter(&lpos);
	ent1->InverseTransform(&pos,&lpos,ent2);

	CKMesh* mesh = ent1->GetCurrentMesh();
	if(!mesh) return -1;
	CKVINDEX* fidx = mesh->GetFacesIndices();
	int fc = mesh->GetFaceCount();

	CKDWORD vStride;
	BYTE* varray = (BYTE*)mesh->GetPositionsPtr(&vStride);

	VxVector bary;
	for(int i=0;i<fc;i++,fidx+=3) {
		if(DotProduct(pos,mesh->GetFaceNormal(i)) > 0.0) {
			p0 = (VxVector*)(varray+fidx[0]*vStride);
			p1 = (VxVector*)(varray+fidx[1]*vStride);
			p2 = (VxVector*)(varray+fidx[2]*vStride);
			bary = (*p0+*p1+*p2)/3.0f;
			
			// fisrst method
			d2 = SquareMagnitude(bary - pos);
			if(d2 < d2min) {
				d2min = d2;
				facemin = i;
			}
			

			/*
			// second method
			d2 = DotProduct(pos-bary,f->FaceNormal);
			if(d2 < d2min) {
				d2min = d2;
				facemin = i;
			}
			*/
			
			/*
			// last method : NOT finshed : need to compare the two scalar product
			d2 = SquareMagnitude(bary - pos);
			if(d2 < d2min) {
				float ps = DotProduct(pos-bary,f->FaceNormal);

				d2min = d2;
				facemin = i;
			}
			*/

		}
	}

	return facemin;
}

//{secret}
int 
CollisionManager::GetNearestFace(CK3dEntity* ent,VxVector& wpos)
{
	CKMesh* mesh = ent->GetCurrentMesh();
	if(!mesh) return -1;

	int fc = mesh->GetFaceCount();
	CKVINDEX* fidx = mesh->GetFacesIndices();

	CKDWORD vStride;
	BYTE* varray = (BYTE*)mesh->GetPositionsPtr(&vStride);

	// we take the position of the given position in the entity referential
	VxVector pos;
	ent->InverseTransform(&pos,&wpos);

	VxVector fpos,bary;
	VxVector* p0;
	float d2,d2min=10000000.0f;
	int facemin=0;
	for(int i=0;i<fc;++i,fidx+=3) {
		p0 = (VxVector*)(varray+*fidx*vStride);
		fpos = pos - *p0;
		if ((d2 = DotProduct(fpos,mesh->GetFaceNormal(i))) > 0.0) {
			
			/*
			p1 = (VxVector*)(varray+fidx[1]*vStride);
			p2 = (VxVector*)(varray+fidx[2]*vStride);
			bary = (*p0+*p1+*p2)*0.3333333f;
			
			// fisrst method
			d2 = SquareMagnitude(bary - pos);
			*/
			if(d2 < d2min) {
				d2min = d2;
				facemin = i;
			}
		}
	}

	return facemin;
}

//{secret}
CKBOOL
CollisionManager::GetNearestVertex(CK3dEntity* ent1,CK3dEntity* ent2,VxVector& nearest)
{
//	float d2,d2min=10000000.0f;
//	int facemin=0;

	VxVector pos1,pos2;
	ent1->GetBaryCenter(&pos2);
	ent1->Transform(&pos2,&pos2);
	ent2->GetBaryCenter(&pos1);
	ent2->Transform(&pos1,&pos1);

	VxIntersectionDesc desc;
	ent1->RayIntersection(&pos1,&pos2,&desc,NULL);
	ent1->Transform(&nearest,&(desc.IntersectionPoint));
	/*
	CKMesh* mesh = ent1->GetCurrentMesh();
	if(!mesh) return FALSE;

	CKDWORD vStride;
	BYTE* varray = (BYTE*)mesh->GetPositionsPtr(&vStride);
	int vcount = mesh->GetVertexCount();

	
	VxVector* p0;
	VxVector bary;
	for(int i=0;i<vcount;i++,varray += vStride) {
		p0 = (VxVector*)varray;

		// fisrst method
		d2 = SquareMagnitude(*p0 - pos);
		if(d2 < d2min) {
			d2min = d2;
			nearest = *p0;
		}
	}
	*/
	
	return TRUE;
}

//{secret}
int
CollisionManager::GetNearestVertex(CK3dEntity* ent,VxVector& wpos)
{
	CKMesh* mesh = ent->GetCurrentMesh();
	if(!mesh) return -1;

	CKDWORD vStride;
	BYTE* varray = (BYTE*)mesh->GetPositionsPtr(&vStride);
	
	int vcount = mesh->GetVertexCount();
	if(!vcount) return -1;
	
	VxVector* p0;
	float d2,d2min=10000000.0f;
	int nearest;
	
	// we take the position of the given position in the entity referential
	VxVector pos;
	ent->InverseTransform(&pos,&wpos);
	
	// we iterate on each vertex to find the closest one from the 
	// position 3d we gave
	for(int i=0;i<vcount;++i,varray += vStride) {
		p0 = (VxVector*)varray;

		// fisrst method
		d2 = SquareMagnitude(*p0 - pos);
		if(d2 < d2min) {
			d2min = d2;
			nearest = i;
		}
	}
	
	return nearest;
}