lovr-ODE/contrib/TerrainAndCone/dTerrainZ.cpp

//Benoit CHAPEROT 2003-2004 www.jstarlab.com
//some code inspired by Magic Software
#include <ode/common.h>
#include <ode/collision.h>
#include <ode/matrix.h>
#include <ode/rotation.h>
#include <ode/odemath.h>
#include "collision_kernel.h"
#include "collision_std.h"
#include "collision_std_internal.h"
#include "collision_util.h"
//#include <drawstuff/drawstuff.h>
#include "windows.h"
#include "ode\ode.h"

#define CONTACT(p,skip) ((dContactGeom*) (((char*)p) + (skip)))
#define MAXCONTACT 10
#define TERRAINTOL 0.0f

static bool IsAPowerOfTwo(int f)
{
	dAASSERT(f!=0);
	while ((f&1) != 1)	
		f >>= 1;

	return (f == 1);
}

static int GetPowerOfTwo(int f)
{
	dAASSERT(f!=0);
	int n = 0;
	while ((f&1) != 1)
	{
		n++;
		f >>= 1;
	}
	
	return n;
}

dxTerrainZ::dxTerrainZ (dSpaceID space, dReal *pHeights,dReal vLength,int nNumNodesPerSide, int bFinite, int bPlaceable) :
dxGeom (space,bPlaceable)
{
	dIASSERT(IsAPowerOfTwo(nNumNodesPerSide));
	dIASSERT(pHeights);
	dIASSERT(vLength > 0.f);
	dIASSERT(nNumNodesPerSide > 0);
	type = dTerrainZClass;
	m_vLength = vLength;
	m_pHeights = new dReal[nNumNodesPerSide * nNumNodesPerSide];
	dIASSERT(m_pHeights);
	m_nNumNodesPerSide = nNumNodesPerSide;
	m_vNodeLength = m_vLength / m_nNumNodesPerSide;
	m_nNumNodesPerSideShift = GetPowerOfTwo(m_nNumNodesPerSide);
	m_nNumNodesPerSideMask  = m_nNumNodesPerSide - 1;
	m_vMinHeight = dInfinity;
	m_vMaxHeight = -dInfinity;
	m_bFinite = bFinite;

	for (int i=0;i<nNumNodesPerSide * nNumNodesPerSide;i++)
	{
		m_pHeights[i] = pHeights[i];
		if (m_pHeights[i] < m_vMinHeight)	m_vMinHeight = m_pHeights[i];
		if (m_pHeights[i] > m_vMaxHeight)	m_vMaxHeight = m_pHeights[i];
	}
}

dxTerrainZ::~dxTerrainZ()
{
	dIASSERT(m_pHeights);
	delete [] m_pHeights;
}

void dxTerrainZ::computeAABB()
{
	if (m_bFinite)
	{
		if (gflags & GEOM_PLACEABLE)
		{
			dReal dx[6],dy[6],dz[6];
			dx[0] = 0;
			dx[1] = final_posr->R[0] * m_vLength;
			dx[2] = 0;
			dx[3] = final_posr->R[1] * m_vLength;
			dx[4] = final_posr->R[2] * m_vMinHeight;
			dx[5] = final_posr->R[2] * m_vMaxHeight;
			
			dy[0] = 0;
			dy[1] = final_posr->R[4] * m_vLength;
			dy[2] = 0;
			dy[3] = final_posr->R[5] * m_vLength;
			dy[4] = final_posr->R[6] * m_vMinHeight;
			dy[5] = final_posr->R[6] * m_vMaxHeight;
			
			dz[0]  = 0;
			dz[1]  = final_posr->R[8] * m_vLength;
			dz[2]  = 0;
			dz[3]  = final_posr->R[9] * m_vLength;
			dz[4]  = final_posr->R[10] * m_vMinHeight;
			dz[5]  = final_posr->R[10] * m_vMaxHeight;

			aabb[0] = final_posr->pos[0] + MIN(dx[0],dx[1]) + MIN(dx[2],dx[3]) + MIN(dx[4],dx[5]);
			aabb[1] = final_posr->pos[0] + MAX(dx[0],dx[1]) + MAX(dx[2],dx[3]) + MAX(dx[4],dx[5]);
			aabb[2] = final_posr->pos[1] + MIN(dy[0],dy[1]) + MIN(dy[2],dy[3]) + MIN(dy[4],dy[5]);
			aabb[3] = final_posr->pos[1] + MAX(dy[0],dy[1]) + MAX(dy[2],dy[3]) + MAX(dy[4],dy[5]);
			aabb[4] = final_posr->pos[2] + MIN(dz[0],dz[1]) + MIN(dz[2],dz[3]) + MIN(dz[4],dz[5]);
			aabb[5] = final_posr->pos[2] + MAX(dz[0],dz[1]) + MAX(dz[2],dz[3]) + MAX(dz[4],dz[5]);
		}
		else
		{
			aabb[0] = 0;
			aabb[1] = m_vLength;
			aabb[2] = 0;
			aabb[3] = m_vLength;
			aabb[4] = m_vMinHeight;
			aabb[5] = m_vMaxHeight;
		}
	}
	else
	{
		if (gflags & GEOM_PLACEABLE)
		{
			aabb[0] = -dInfinity;
			aabb[1] = dInfinity;
			aabb[2] = -dInfinity;
			aabb[3] = dInfinity;
			aabb[4] = -dInfinity;
			aabb[5] = dInfinity;
		}
		else
		{
			aabb[0] = -dInfinity;
			aabb[1] = dInfinity;
			aabb[2] = -dInfinity;
			aabb[3] = dInfinity;
			aabb[4] = m_vMinHeight;
			aabb[5] = m_vMaxHeight;
		}
	}
}

dReal dxTerrainZ::GetHeight(int x,int y)
{
	return m_pHeights[	(((unsigned int)(y) & m_nNumNodesPerSideMask) << m_nNumNodesPerSideShift)
					+	 ((unsigned int)(x) & m_nNumNodesPerSideMask)];
}

dReal dxTerrainZ::GetHeight(dReal x,dReal y)
{
	int nX		= int(floor(x / m_vNodeLength));
	int nY		= int(floor(y / m_vNodeLength));
	dReal dx	= (x - (dReal(nX) * m_vNodeLength)) / m_vNodeLength;
	dReal dy	= (y - (dReal(nY) * m_vNodeLength)) / m_vNodeLength;
	dIASSERT((dx >= 0.f) && (dx <= 1.f));
	dIASSERT((dy >= 0.f) && (dy <= 1.f));

	dReal z,z0;
	
	if (dx + dy < 1.f)
	{
		z0	= GetHeight(nX,nY);
		z	= z0	
			+ (GetHeight(nX+1,nY) - z0) * dx
			+ (GetHeight(nX,nY+1) - z0) * dy;
	}
	else
	{
		z0	= GetHeight(nX+1,nY+1);
		z	= z0	
			+ (GetHeight(nX+1,nY) - z0) * (1.f - dy)
			+ (GetHeight(nX,nY+1) - z0) * (1.f - dx);
	}

	return z;	
}

bool dxTerrainZ::IsOnTerrain(int nx,int ny,int w,dReal *pos)
{
	dVector3 Min,Max;
	Min[0] = nx * m_vNodeLength;
	Min[1] = ny * m_vNodeLength;
	Max[0] = (nx+1) * m_vNodeLength;
	Max[1] = (ny+1) * m_vNodeLength;
	dReal Tol = m_vNodeLength * TERRAINTOL;
	
	if ((pos[0]<Min[0]-Tol) || (pos[0]>Max[0]+Tol))
		return false;

	if ((pos[1]<Min[1]-Tol) || (pos[1]>Max[1]+Tol))
		return false;

	dReal dx	= (pos[0] - (dReal(nx) * m_vNodeLength)) / m_vNodeLength;
	dReal dy	= (pos[1] - (dReal(ny) * m_vNodeLength)) / m_vNodeLength;

	if ((w == 0) && (dx + dy > 1.f+TERRAINTOL))
		return false;

	if ((w == 1) && (dx + dy < 1.f-TERRAINTOL))
		return false;

	return true;
}

dGeomID dCreateTerrainZ(dSpaceID space, dReal *pHeights,dReal vLength,int nNumNodesPerSide, int bFinite, int bPlaceable)
{
	return new dxTerrainZ(space, pHeights,vLength,nNumNodesPerSide, bFinite, bPlaceable);
}

dReal dGeomTerrainZPointDepth (dGeomID g, dReal x, dReal y, dReal z)
{
	dUASSERT (g && g->type == dTerrainZClass,"argument not a terrain");
  g->recomputePosr();
	dxTerrainZ *t = (dxTerrainZ*) g;
	return t->GetHeight(x,y) - z;
}

typedef dReal dGetDepthFn(dGeomID g, dReal x, dReal y, dReal z);
#define RECOMPUTE_RAYNORMAL
//#define DO_RAYDEPTH

#define DMESS(A)	\
			dMessage(0,"Contact Plane (%d %d %d) %.5e %.5e (%.5e %.5e %.5e)(%.5e %.5e %.5e)).",	\
					x,y,A,	\
					pContact->depth,	\
					dGeomSphereGetRadius(o2),		\
					pContact->pos[0],	\
					pContact->pos[1],	\
					pContact->pos[2],	\
					pContact->normal[0],	\
					pContact->normal[1],	\
					pContact->normal[2]);
/*
(z is up)

y
.
F
|
C-D
|\|
A-B-E.x
*/
int dxTerrainZ::dCollideTerrainUnit(
	int x,int y,dxGeom *o2,int numMaxContacts,
	int flags,dContactGeom *contact, int skip)
{
	dColliderFn *CollideRayN;
	dColliderFn *CollideNPlane;
	dGetDepthFn *GetDepth;
	int numContacts = 0;
	int numPlaneContacts = 0;
	int i;
	
	if (numContacts == numMaxContacts)
		return numContacts;

	dContactGeom PlaneContact[MAXCONTACT];
	flags = (flags & 0xffff0000) | MAXCONTACT;
	
	switch (o2->type)
	{
	case dSphereClass:
		CollideRayN		= dCollideRaySphere;
		CollideNPlane	= dCollideSpherePlane;
		GetDepth		= dGeomSpherePointDepth;
		break;
	case dBoxClass:
		CollideRayN		= dCollideRayBox;
		CollideNPlane	= dCollideBoxPlane;
		GetDepth		= dGeomBoxPointDepth;
		break;
	case dCCylinderClass:
		CollideRayN		= dCollideRayCCylinder;
		CollideNPlane	= dCollideCCylinderPlane;
		GetDepth		= dGeomCCylinderPointDepth;
		break;
	case dRayClass:
		CollideRayN		= NULL;
		CollideNPlane	= dCollideRayPlane;
		GetDepth		= NULL;
		break;
	case dConeClass:
		CollideRayN		= dCollideRayCone;
		CollideNPlane	= dCollideConePlane;
		GetDepth		= dGeomConePointDepth;
		break;
	default:
		dIASSERT(0);
	}

	dReal Plane[4],lBD,lCD,lBC;
	dVector3 A,B,C,D,BD,CD,BC,AB,AC;
	A[0] = x * m_vNodeLength;
	A[1] = y * m_vNodeLength;
	A[2] = GetHeight(x,y);
	B[0] = (x+1) * m_vNodeLength;
	B[1] = y * m_vNodeLength;
	B[2] = GetHeight(x+1,y);
	C[0] = x * m_vNodeLength;
	C[1] = (y+1) * m_vNodeLength;
	C[2] = GetHeight(x,y+1);
	D[0] = (x+1) * m_vNodeLength;
	D[1] = (y+1) * m_vNodeLength;
	D[2] = GetHeight(x+1,y+1);

	dOP(BC,-,C,B);
	lBC = dLENGTH(BC);
	dOPEC(BC,/=,lBC);

	dOP(BD,-,D,B);
	lBD = dLENGTH(BD);
	dOPEC(BD,/=,lBD);

	dOP(CD,-,D,C);
	lCD = dLENGTH(CD);
	dOPEC(CD,/=,lCD);

	dOP(AB,-,B,A);
	dNormalize3(AB);

	dOP(AC,-,C,A);
	dNormalize3(AC);

	if (CollideRayN)
	{
#ifdef RECOMPUTE_RAYNORMAL
		dVector3 E,F;
		dVector3 CE,FB,AD;
		dVector3 Normal[3];
		E[0] = (x+2) * m_vNodeLength;
		E[1] = y * m_vNodeLength;
		E[2] = GetHeight(x+2,y);
		F[0] = x * m_vNodeLength;
		F[1] = (y+2) * m_vNodeLength;
		F[2] = GetHeight(x,y+2);
		dOP(AD,-,D,A);
		dNormalize3(AD);
		dOP(CE,-,E,C);
		dNormalize3(CE);
		dOP(FB,-,B,F);
		dNormalize3(FB);

		//BC
		dCROSS(Normal[0],=,AD,BC);
		dNormalize3(Normal[0]);

		//BD
		dCROSS(Normal[1],=,CE,BD);
		dNormalize3(Normal[1]);

		//CD
		dCROSS(Normal[2],=,FB,CD);
		dNormalize3(Normal[2]);
#endif		
		int nA[3],nB[3];
		dContactGeom ContactA[3],ContactB[3];
		dxRay rayBC(0,lBC);	
		dGeomRaySet(&rayBC, B[0], B[1], B[2], BC[0], BC[1], BC[2]);
		nA[0] = CollideRayN(&rayBC,o2,flags,&ContactA[0],sizeof(dContactGeom));
		dGeomRaySet(&rayBC, C[0], C[1], C[2], -BC[0], -BC[1], -BC[2]);
		nB[0] = CollideRayN(&rayBC,o2,flags,&ContactB[0],sizeof(dContactGeom));
		
		dxRay rayBD(0,lBD);	
		dGeomRaySet(&rayBD, B[0], B[1], B[2], BD[0], BD[1], BD[2]);
		nA[1] = CollideRayN(&rayBD,o2,flags,&ContactA[1],sizeof(dContactGeom));
		dGeomRaySet(&rayBD, D[0], D[1], D[2], -BD[0], -BD[1], -BD[2]);
		nB[1] = CollideRayN(&rayBD,o2,flags,&ContactB[1],sizeof(dContactGeom));
	
		dxRay rayCD(0,lCD);	
		dGeomRaySet(&rayCD, C[0], C[1], C[2], CD[0], CD[1], CD[2]);
		nA[2] = CollideRayN(&rayCD,o2,flags,&ContactA[2],sizeof(dContactGeom));
		dGeomRaySet(&rayCD, D[0], D[1], D[2], -CD[0], -CD[1], -CD[2]);
		nB[2] = CollideRayN(&rayCD,o2,flags,&ContactB[2],sizeof(dContactGeom));
	
		for (i=0;i<3;i++)
		{
			if (nA[i] & nB[i])
			{
				dContactGeom *pContact = CONTACT(contact,numContacts*skip);
				pContact->pos[0] = (ContactA[i].pos[0] + ContactB[i].pos[0])/2;
				pContact->pos[1] = (ContactA[i].pos[1] + ContactB[i].pos[1])/2;
				pContact->pos[2] = (ContactA[i].pos[2] + ContactB[i].pos[2])/2;
#ifdef RECOMPUTE_RAYNORMAL
				pContact->normal[0] = -Normal[i][0];
				pContact->normal[1] = -Normal[i][1];
				pContact->normal[2] = -Normal[i][2];
#else
				pContact->normal[0] = (ContactA[i].normal[0] + ContactB[i].normal[0])/2;	//0.f;
				pContact->normal[1] = (ContactA[i].normal[1] + ContactB[i].normal[1])/2;	//0.f;
				pContact->normal[2] = (ContactA[i].normal[2] + ContactB[i].normal[2])/2;	//-1.f;
				dNormalize3(pContact->normal);
#endif
#ifdef DO_RAYDEPTH
				dxRay rayV(0,1000.f);
				dGeomRaySet(&rayV,	pContact->pos[0],
									pContact->pos[1],
									pContact->pos[2],
									-pContact->normal[0],
									-pContact->normal[1],
									-pContact->normal[2]);
		
				dContactGeom ContactV;
				if (CollideRayN(&rayV,o2,flags,&ContactV,sizeof(dContactGeom)))
				{
					pContact->depth = ContactV.depth;
					numContacts++;	
				}
#else
            if (GetDepth == NULL)
               {
				   dxRay rayV(0,1000.f);
				   dGeomRaySet(&rayV,	pContact->pos[0],
									   pContact->pos[1],
									   pContact->pos[2],
									   -pContact->normal[0],
									   -pContact->normal[1],
									   -pContact->normal[2]);
		
				   dContactGeom ContactV;
				   if (CollideRayN(&rayV,o2,flags,&ContactV,sizeof(dContactGeom)))
				   {
					   pContact->depth = ContactV.depth;
					   numContacts++;	
				   }
               }
            else
               {
				   pContact->depth =  GetDepth(o2,
				   pContact->pos[0],
				   pContact->pos[1],
				   pContact->pos[2]);
				   numContacts++;
               }
#endif
				if (numContacts == numMaxContacts)
					return numContacts;

			}
		}
	}

	dCROSS(Plane,=,AB,AC);
	dNormalize3(Plane);
	Plane[3] = Plane[0] * A[0] + Plane[1] * A[1] + Plane[2] * A[2];
	dxPlane planeABC(0,Plane[0],Plane[1],Plane[2],Plane[3]);
	numPlaneContacts = CollideNPlane(o2,&planeABC,flags,PlaneContact,sizeof(dContactGeom));

	for (i=0;i<numPlaneContacts;i++)
	{
		if (IsOnTerrain(x,y,0,PlaneContact[i].pos))
		{
			dContactGeom *pContact = CONTACT(contact,numContacts*skip);
			pContact->pos[0] = PlaneContact[i].pos[0];
			pContact->pos[1] = PlaneContact[i].pos[1];
			pContact->pos[2] = PlaneContact[i].pos[2];
			pContact->normal[0] = -PlaneContact[i].normal[0];
			pContact->normal[1] = -PlaneContact[i].normal[1];
			pContact->normal[2] = -PlaneContact[i].normal[2];
			pContact->depth = PlaneContact[i].depth;

			//DMESS(0);
			numContacts++;

			if (numContacts == numMaxContacts)
					return numContacts;
		}
	}

	dCROSS(Plane,=,CD,BD);
	dNormalize3(Plane);
	Plane[3] = Plane[0] * D[0] + Plane[1] * D[1] + Plane[2] * D[2];
	dxPlane planeDCB(0,Plane[0],Plane[1],Plane[2],Plane[3]);
	numPlaneContacts = CollideNPlane(o2,&planeDCB,flags,PlaneContact,sizeof(dContactGeom));

	for (i=0;i<numPlaneContacts;i++)
	{
		if (IsOnTerrain(x,y,1,PlaneContact[i].pos))
		{
			dContactGeom *pContact = CONTACT(contact,numContacts*skip);
			pContact->pos[0] = PlaneContact[i].pos[0];
			pContact->pos[1] = PlaneContact[i].pos[1];
			pContact->pos[2] = PlaneContact[i].pos[2];
			pContact->normal[0] = -PlaneContact[i].normal[0];
			pContact->normal[1] = -PlaneContact[i].normal[1];
			pContact->normal[2] = -PlaneContact[i].normal[2];
			pContact->depth = PlaneContact[i].depth;
			//DMESS(1);
			numContacts++;

			if (numContacts == numMaxContacts)
					return numContacts;
		}
	}

	return numContacts;
}

int dCollideTerrainZ(dxGeom *o1, dxGeom *o2, int flags,dContactGeom *contact, int skip)
{
	dIASSERT (skip >= (int)sizeof(dContactGeom));
	dIASSERT (o1->type == dTerrainZClass);
	int i,j;

	if ((flags & 0xffff) == 0)
		flags = (flags & 0xffff0000) | 1;

	int numMaxTerrainContacts = (flags & 0xffff);
	dxTerrainZ *terrain = (dxTerrainZ*) o1;

	dReal aabbbak[6];
	int gflagsbak;

	dVector3 pos0;
	int numTerrainContacts = 0;

	dxPosR *bak;
   dxPosR X1;

	if (terrain->gflags & GEOM_PLACEABLE)
	{
		dOP(pos0,-,o2->final_posr->pos,terrain->final_posr->pos);
		dMULTIPLY1_331(X1.pos,terrain->final_posr->R,pos0);
		dMULTIPLY1_333(X1.R,terrain->final_posr->R,o2->final_posr->R);
		bak = o2->final_posr;
		o2->final_posr = &X1;
		memcpy(aabbbak,o2->aabb,sizeof(dReal)*6);
		gflagsbak = o2->gflags;
		o2->computeAABB();
	}

	int nMinX	= int(floor(o2->aabb[0] / terrain->m_vNodeLength));
	int nMaxX	= int(floor(o2->aabb[1] / terrain->m_vNodeLength)) + 1;
	int nMinY	= int(floor(o2->aabb[2] / terrain->m_vNodeLength));
	int nMaxY	= int(floor(o2->aabb[3] / terrain->m_vNodeLength)) + 1;

	if (terrain->m_bFinite)
	{
		nMinX = MAX(nMinX,0);
		nMaxX = MIN(nMaxX,terrain->m_nNumNodesPerSide);
		nMinY = MAX(nMinY,0);
		nMaxY = MIN(nMaxY,terrain->m_nNumNodesPerSide);

		if ((nMinX >= nMaxX) || (nMinY >= nMaxY))
			goto dCollideTerrainZExit;
	}

	dVector3 AabbTop;
	AabbTop[0] = (o2->aabb[0]+o2->aabb[1]) / 2;
	AabbTop[1] = (o2->aabb[2]+o2->aabb[3]) / 2;
	AabbTop[2] = o2->aabb[5];
	if (o2->type != dRayClass)
	{
		dReal AabbTopDepth = terrain->GetHeight(AabbTop[0],AabbTop[1]) - AabbTop[2];
		if (AabbTopDepth > 0.f)
		{
			contact->depth = AabbTopDepth;
			dReal MaxDepth = (o2->aabb[5]-o2->aabb[4]) / 2;
			if (contact->depth > MaxDepth)
				contact->depth = MaxDepth;
			contact->g1 = o1;
			contact->g2 = o2;
			dOPE(contact->pos,=,AabbTop);
			contact->normal[0] = 0.f;
			contact->normal[1] = 0.f;
			contact->normal[2] = -1.f;

			numTerrainContacts = 1;
			goto dCollideTerrainZExit;
		}
	}
	
	for (i=nMinX;i<nMaxX;i++)
	{
		for (j=nMinY;j<nMaxY;j++)
		{
			numTerrainContacts += terrain->dCollideTerrainUnit(
				i,j,o2,numMaxTerrainContacts - numTerrainContacts,
				flags,CONTACT(contact,numTerrainContacts*skip),skip	);
		}
	}

	dIASSERT(numTerrainContacts <= numMaxTerrainContacts);

	for (i=0; i<numTerrainContacts; i++) 
	{
		CONTACT(contact,i*skip)->g1 = o1;
		CONTACT(contact,i*skip)->g2 = o2;
	}

dCollideTerrainZExit:

	if (terrain->gflags & GEOM_PLACEABLE)
	{
      o2->final_posr = bak;
		memcpy(o2->aabb,aabbbak,sizeof(dReal)*6);
		o2->gflags = gflagsbak;

		for (i=0; i<numTerrainContacts; i++) 
		{
			dOPE(pos0,=,CONTACT(contact,i*skip)->pos);
			dMULTIPLY0_331(CONTACT(contact,i*skip)->pos,terrain->final_posr->R,pos0);
			dOP(CONTACT(contact,i*skip)->pos,+,CONTACT(contact,i*skip)->pos,terrain->final_posr->pos);

			dOPE(pos0,=,CONTACT(contact,i*skip)->normal);
			dMULTIPLY0_331(CONTACT(contact,i*skip)->normal,terrain->final_posr->R,pos0);
		}
	}

	return numTerrainContacts;
}
/*
void dsDrawTerrainZ(int x,int z,float vLength,float vNodeLength,int nNumNodesPerSide,float *pHeights,const float *pR,const float *ppos)
{
	float A[3],B[3],C[3],D[3];
	float R[12];
	float pos[3];
	if (pR)
		memcpy(R,pR,sizeof(R));
	else
	{
		memset(R,0,sizeof(R));
		R[0] = 1.f;
		R[5] = 1.f;
		R[10] = 1.f;
	}
	
	if (ppos)
		memcpy(pos,ppos,sizeof(pos));
	else
		memset(pos,0,sizeof(pos));
	
	float vx,vz;
	vx = vLength * x;
	vz = vLength * z;
	
	int i;
	for (i=0;i<nNumNodesPerSide;i++)
	{
		for (int j=0;j<nNumNodesPerSide;j++)
		{
			A[0] = i * vNodeLength + vx;
			A[1] = j * vNodeLength + vz;
			A[2] = GetHeight(i,j,nNumNodesPerSide,pHeights);
			B[0] = (i+1) * vNodeLength + vx;
			B[1] = j * vNodeLength + vz;
			B[2] = GetHeight(i+1,j,nNumNodesPerSide,pHeights);
			C[0] = i * vNodeLength + vx;
			C[1] = (j+1) * vNodeLength + vz;
			C[2] = GetHeight(i,j+1,nNumNodesPerSide,pHeights);
			D[0] = (i+1) * vNodeLength + vx;
			D[1] = (j+1) * vNodeLength + vz;
			D[2] = GetHeight(i+1,j+1,nNumNodesPerSide,pHeights);
			dsDrawTriangle(pos,R,C,A,B,1);
			dsDrawTriangle(pos,R,D,C,B,1);
		}
	}
}
*/