bezierEval.h File Reference

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Functions
void	bezierCurveEval (float u0, float u1, int order, float *ctlpoints, int stride, int dimension, float u, float retpoint[])
void	bezierCurveEvalDer (float u0, float u1, int order, float *ctlpoints, int stride, int dimension, float u, float retDer[])
void	bezierCurveEvalDerGen (int der, float u0, float u1, int order, float *ctlpoints, int stride, int dimension, float u, float retDer[])
void	bezierSurfEvalDerGen (int uder, int vder, float u0, float u1, int uorder, float v0, float v1, int vorder, int dimension, float *ctlpoints, int ustride, int vstride, float u, float v, float ret[])
void	bezierSurfEval (float u0, float u1, int uorder, float v0, float v1, int vorder, int dimension, float *ctlpoints, int ustride, int vstride, float u, float v, float ret[])
void	bezierSurfEvalNormal (float u0, float u1, int uorder, float v0, float v1, int vorder, int dimension, float *ctlpoints, int ustride, int vstride, float u, float v, float retNormal[])

Function Documentation

bezierCurveEval()

void bezierCurveEval	(	float	u0,
		float	u1,
		int	order,
		float *	ctlpoints,
		int	stride,
		int	dimension,
		float	u,
		float	retpoint[]
	)

Definition at line 75 of file bezierEval.cc.

{
  float uprime = (u-u0)/(u1-u0);
  float *ctlptr = ctlpoints;
  float oneMinusX = 1.0f-uprime;
  float XPower = 1.0f;
 
  int i,k;
  for(k=0; k<dimension; k++)
    retpoint[k] = (*(ctlptr + k));
 
  for(i=1; i<order; i++){
    ctlptr += stride;
    XPower *= uprime;
    for(k=0; k<dimension; k++) {
      retpoint[k] = retpoint[k]*oneMinusX + ctlptr[k]* binomialCoefficients[order-1][i] * XPower;
    }
  }
}

Referenced by bezierCurveEvalDer(), and bezierCurveEvalDerGen().

bezierCurveEvalDer()

void bezierCurveEvalDer	(	float	u0,
		float	u1,
		int	order,
		float *	ctlpoints,
		int	stride,
		int	dimension,
		float	u,
		float	retDer[]
	)

Definition at line 125 of file bezierEval.cc.

{
  int i,k;
  float width = u1-u0;
  float *ctlptr = ctlpoints;
 
  float buf[MAX_ORDER][MAX_DIMENSION];
  if(order == 1){
    for(k=0; k<dimension; k++)
      retDer[k]=0;
  }
  for(i=0; i<order-1; i++){
    for(k=0; k<dimension; k++) {
      buf[i][k] = (ctlptr[stride+k] - ctlptr[k])*(order-1)/width;
    }
    ctlptr += stride;
  }
 
  bezierCurveEval(u0, u1, order-1, (float*) buf, MAX_DIMENSION,  dimension, u, retDer);
}

bezierCurveEvalDerGen()

void bezierCurveEvalDerGen	(	int	der,
		float	u0,
		float	u1,
		int	order,
		float *	ctlpoints,
		int	stride,
		int	dimension,
		float	u,
		float	retDer[]
	)

Definition at line 146 of file bezierEval.cc.

{
  int i,k,r;
  float *ctlptr = ctlpoints;
  float width=u1-u0;
  float buf[MAX_ORDER][MAX_ORDER][MAX_DIMENSION];
  if(der<0) der=0;
  for(i=0; i<order; i++){
    for(k=0; k<dimension; k++){
      buf[0][i][k] = ctlptr[k];
    }
    ctlptr += stride;
  }
 
 
  for(r=1; r<=der; r++){
    for(i=0; i<order-r; i++){
      for(k=0; k<dimension; k++){
    buf[r][i][k] = (buf[r-1][i+1][k] - buf[r-1][i][k])*(order-r)/width;
      }
    }
  }
 
  bezierCurveEval(u0, u1, order-der, (float *) (buf[der]), MAX_DIMENSION, dimension, u, retDer);
}

Referenced by bezierSurfEvalDerGen().

bezierSurfEval()

void bezierSurfEval	(	float	u0,
		float	u1,
		int	uorder,
		float	v0,
		float	v1,
		int	vorder,
		int	dimension,
		float *	ctlpoints,
		int	ustride,
		int	vstride,
		float	u,
		float	v,
		float	ret[]
	)

Definition at line 192 of file bezierEval.cc.

{
  bezierSurfEvalDerGen(0, 0, u0, u1, uorder, v0, v1, vorder, dimension, ctlpoints, ustride, vstride, u, v, ret);
  if(dimension == 4) /*homogeneous*/{
    ret[0] /= ret[3];
    ret[1] /= ret[3];
    ret[2] /= ret[3];
  }
}

Referenced by bezierPatchEval(), and bezierPatchMeshEval().

bezierSurfEvalDerGen()

void bezierSurfEvalDerGen	(	int	uder,
		int	vder,
		float	u0,
		float	u1,
		int	uorder,
		float	v0,
		float	v1,
		int	vorder,
		int	dimension,
		float *	ctlpoints,
		int	ustride,
		int	vstride,
		float	u,
		float	v,
		float	ret[]
	)

Definition at line 176 of file bezierEval.cc.

{
  int i;
  float newPoints[MAX_ORDER][MAX_DIMENSION];
 
  for(i=0; i<uorder; i++){
 
    bezierCurveEvalDerGen(vder, v0, v1, vorder, ctlpoints+ustride*i, vstride, dimension, v, newPoints[i]);
 
  }
 
  bezierCurveEvalDerGen(uder, u0, u1, uorder, (float *) newPoints, MAX_DIMENSION, dimension, u, ret);
}

Referenced by bezierSurfEval(), and bezierSurfEvalNormal().

bezierSurfEvalNormal()

void bezierSurfEvalNormal	(	float	u0,
		float	u1,
		int	uorder,
		float	v0,
		float	v1,
		int	vorder,
		int	dimension,
		float *	ctlpoints,
		int	ustride,
		int	vstride,
		float	u,
		float	v,
		float	retNormal[]
	)

Definition at line 202 of file bezierEval.cc.

{
  float partialU[4];
  float partialV[4];
  assert(dimension>=3 && dimension <=4);
  bezierSurfEvalDerGen(1,0, u0, u1, uorder, v0, v1, vorder, dimension, ctlpoints, ustride, vstride, u, v, partialU);
  bezierSurfEvalDerGen(0,1, u0, u1, uorder, v0, v1, vorder, dimension, ctlpoints, ustride, vstride, u, v, partialV);
 
  if(dimension == 3){/*inhomogeneous*/
    crossProduct(partialU, partialV, retNormal);
 
    normalize(retNormal);
 
    return;
  }
  else { /*homogeneous*/
    float val[4]; /*the point coordinates (without derivative)*/
    float newPartialU[MAX_DIMENSION];
    float newPartialV[MAX_DIMENSION];
    int i;
    bezierSurfEvalDerGen(0,0, u0, u1, uorder, v0, v1, vorder, dimension, ctlpoints, ustride, vstride, u, v, val);
 
    for(i=0; i<=2; i++){
      newPartialU[i] = partialU[i] * val[3] - val[i] * partialU[3];
      newPartialV[i] = partialV[i] * val[3] - val[i] * partialV[3];
    }
    crossProduct(newPartialU, newPartialV, retNormal);
    normalize(retNormal);
  }
}

Referenced by bezierPatchEvalNormal(), and bezierPatchMeshEval().