/// standard object services ---------------------------------------------------
public Camera(StreamReader infile)
{
// read and condition view definition
ViewPosition = new Vector(infile);
viewDirection = new Vector(infile);
viewAngle = infile.ReadFloat();
viewDirection = viewDirection.Unitize();
if (viewDirection.IsZero())
viewDirection = new Vector(0.0f, 0.0f, 1.0f);
if (viewAngle < 10) viewAngle = 10;
if (viewAngle > 160) viewAngle = 160;
viewAngle *= (float)(Math.PI / 180);
// make other directions of frame
up = new Vector(0.0f, 1.0f, 0.0f);
right = up.Cross(viewDirection).Unitize();
if (!right.IsZero())
up = viewDirection.Cross(right).Unitize();
else
{
up = new Vector(0.0f, 0.0f, viewDirection[1] < 0.0f ? 1.0f : -1.0f);
right = up.Cross(viewDirection).Unitize();
}
} // Camera
/*
* @implementation
* Adapted from:
* <cite>'Fast, Minimum Storage Ray-Triangle Intersection'
* Moller, Trumbore;
* Journal Of Graphics Tools, v2n1p21, 1997.
* http://www.acm.org/jgt/papers/MollerTrumbore97/</cite>
*/
public bool GetIntersection(Vector rayOrigin, Vector rayDirection, ref float hitDistance)
{
// begin calculating determinant - also used to calculate U parameter
Vector pvec = rayDirection.Cross(edge2);
// if determinant is near zero, ray lies in plane of triangle
float det = edge1.Dot(pvec);
const float EPSILON = 0.000001f;
if ((det > -EPSILON) && (det < EPSILON))
return false;
float inv_det = 1.0f / det;
// calculate distance from vertex 0 to ray origin
Vector tvec = rayOrigin - verts[0];
// calculate U parameter and test bounds
float u = tvec.Dot(pvec) * inv_det;
if ((u < 0.0f) || (u > 1.0f))
return false;
// prepare to test V parameter
Vector qvec = tvec.Cross(edge1);
// calculate V parameter and test bounds
float v = rayDirection.Dot(qvec) * inv_det;
if ((v < 0.0f) || (u + v > 1.0f))
return false;
// calculate t, ray intersects triangle
hitDistance = edge2.Dot(qvec) * inv_det;
// only allow intersections in the forward ray direction
return hitDistance >= 0.0f;
}