//Calculate an Up vector
vec3 CArcBallCamera::getUp()
{
float o = (m_omega + PiOver2);
float ph = Absolutef(m_phi - PiOver2);
vec3 p;
p.x = (m_rho * cos(o) * sin(ph));
p.z = (m_rho * sin(o) * sin(ph));
p.y = (m_rho * cos(ph));
p.normalize();
return p;
}
float ComputeTriangleSquareDist(vec3f vertices[3], vec3f p, vec3f& outClosestPoint, vec3f& outBaryCoords)
{
vec3f dif = vertices[0] - p;
vec3f edge0 = vertices[1] - vertices[0];
vec3f edge1 = vertices[2] - vertices[0];
float a00 = edge0.length2();
float a01 = edge0.dot(edge1);
float a11 = edge1.length2();
float b0 = dif.dot(edge0);
float b1 = dif.dot(edge1);
float c = dif.length2();
float det = Absolutef(a00 * a11 - a01*a01);
float s = a01*b1 - a11*b0;
float t = a01*b0 - a00*b1;
float sqrDistance;
//Conditions
if (s + t <= det)
{
if (s < (float)0)
{
if (t < (float)0) // region 4
{
if (b0 < (float)0)
{
t = (float)0;
if (-b0 >= a00)
{
s = (float)1;
sqrDistance = a00 + ((float)2)*b0 + c;
}
else
{
s = -b0/a00;
sqrDistance = b0*s + c;
}
}
else
{
s = (float)0;
if (b1 >= (float)0)
{
t = (float)0;
sqrDistance = c;
}
else if (-b1 >= a11)
{
t = (float)1;
sqrDistance = a11 + ((float)2)*b1 + c;
}
else
{
t = -b1/a11;
sqrDistance = b1*t + c;
}
}
}
else // region 3
{
s = (float)0;
if (b1 >= (float)0)
{
t = (float)0;
sqrDistance = c;
}
else if (-b1 >= a11)
{
t = (float)1;
sqrDistance = a11 + ((float)2)*b1 + c;
}
else
{
t = -b1/a11;
sqrDistance = b1*t + c;
}
}
}
else if (t < (float)0) // region 5
{
t = (float)0;
if (b0 >= (float)0)
{
s = (float)0;
sqrDistance = c;
}
else if (-b0 >= a00)
{
s = (float)1;
sqrDistance = a00 + ((float)2)*b0 + c;
}
else
{
s = -b0/a00;
sqrDistance = b0*s + c;
}
}
else // region 0
{
// minimum at interior point
float invDet = ((float)1)/det;
s *= invDet;
t *= invDet;
sqrDistance = s*(a00*s + a01*t + ((float)2)*b0) +
t*(a01*s + a11*t + ((float)2)*b1) + c;
}
}
else
{
float tmp0, tmp1, numer, denom;
if (s < (float)0) // region 2
{
tmp0 = a01 + b0;
tmp1 = a11 + b1;
if (tmp1 > tmp0)
{
numer = tmp1 - tmp0;
denom = a00 - ((float)2)*a01 + a11;
if (numer >= denom)
{
s = (float)1;
t = (float)0;
sqrDistance = a00 + ((float)2)*b0 + c;
}
else
{
s = numer/denom;
t = (float)1 - s;
sqrDistance = s*(a00*s + a01*t + ((float)2)*b0) +
t*(a01*s + a11*t + ((float)2)*b1) + c;
}
}
else
{
s = (float)0;
if (tmp1 <= (float)0)
{
t = (float)1;
sqrDistance = a11 + ((float)2)*b1 + c;
}
else if (b1 >= (float)0)
{
t = (float)0;
sqrDistance = c;
}
else
{
t = -b1/a11;
sqrDistance = b1*t + c;
}
}
}
else if (t < (float)0) // region 6
{
tmp0 = a01 + b1;
tmp1 = a00 + b0;
if (tmp1 > tmp0)
{
numer = tmp1 - tmp0;
denom = a00 - ((float)2)*a01 + a11;
if (numer >= denom)
{
t = (float)1;
s = (float)0;
sqrDistance = a11 + ((float)2)*b1 + c;
}
else
{
t = numer/denom;
s = (float)1 - t;
sqrDistance = s*(a00*s + a01*t + ((float)2)*b0) +
t*(a01*s + a11*t + ((float)2)*b1) + c;
}
}
else
{
t = (float)0;
if (tmp1 <= (float)0)
{
s = (float)1;
sqrDistance = a00 + ((float)2)*b0 + c;
}
else if (b0 >= (float)0)
{
s = (float)0;
sqrDistance = c;
}
else
{
s = -b0/a00;
sqrDistance = b0*s + c;
}
}
}
else // region 1
{
numer = a11 + b1 - a01 - b0;
if (numer <= (float)0)
{
s = (float)0;
t = (float)1;
sqrDistance = a11 + ((float)2)*b1 + c;
}
else
{
denom = a00 - ((float)2)*a01 + a11;
if (numer >= denom)
{
s = (float)1;
t = (float)0;
sqrDistance = a00 + ((float)2)*b0 + c;
}
else
{
s = numer/denom;
t = (float)1 - s;
sqrDistance = s*(a00*s + a01*t + ((float)2)*b0) +
t*(a01*s + a11*t + ((float)2)*b1) + c;
}
}
}
}
// Account for numerical round-off error.
if (sqrDistance < (float)0)
{
sqrDistance = (float)0;
}
//mClosestPoint0 = *mPoint;
outClosestPoint = vertices[0] + s*edge0 + t*edge1;
outBaryCoords.y = s;
outBaryCoords.z = t;
outBaryCoords.x = (float)1 - s - t;
return sqrDistance;
}
