/**
* @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>
*/
bool TriangleIntersection
(
const Triangle* pT,
const Vector3f* pRayOrigin,
const Vector3f* pRayDirection,
real64* pHitDistance_o
)
{
/* make vectors for two edges sharing vert0 */
const Vector3f edge1 = Vector3fSub( &pT->aVertexs[1], &pT->aVertexs[0] );
const Vector3f edge2 = Vector3fSub( &pT->aVertexs[2], &pT->aVertexs[0] );
/* begin calculating determinant - also used to calculate U parameter */
const Vector3f pvec = Vector3fCross( pRayDirection, &edge2 );
/* if determinant is near zero, ray lies in plane of triangle */
const real64 det = Vector3fDot( &edge1, &pvec );
bool isHit = false;
if( (det <= -EPSILON) | (det >= EPSILON) )
{
const real64 inv_det = 1.0 / det;
/* calculate distance from vertex 0 to ray origin */
const Vector3f tvec = Vector3fSub( pRayOrigin, &pT->aVertexs[0] );
/* calculate U parameter and test bounds */
const real64 u = Vector3fDot( &tvec, &pvec ) * inv_det;
if( (u >= 0.0) & (u <= 1.0) )
{
/* prepare to test V parameter */
const Vector3f qvec = Vector3fCross( &tvec, &edge1 );
/* calculate V parameter and test bounds */
const real64 v = Vector3fDot( pRayDirection, &qvec ) * inv_det;
if( (v >= 0.0) & (u + v <= 1.0) )
{
/* calculate t, ray intersects triangle */
*pHitDistance_o = Vector3fDot( &edge2, &qvec ) * inv_det;
/* only allow intersections in the forward ray direction */
isHit = (*pHitDistance_o >= 0.0);
}
}
}
return isHit;
}
//Mouse drag, calculate rotation
void ArcBall_t::drag(const Point2fT* NewPt, Quat4fT* NewRot)
{
//Map the point to the sphere
this->_mapToSphere(NewPt, &this->EnVec);
//Return the quaternion equivalent to the rotation
if (NewRot)
{
Vector3fT Perp;
//Compute the vector perpendicular to the begin and end vectors
Vector3fCross(&Perp, &this->StVec, &this->EnVec);
//Compute the length of the perpendicular vector
if (Vector3fLength(&Perp) > Epsilon) //if its non-zero
{
//We're ok, so return the perpendicular vector as the transform after all
NewRot->s.X = Perp.s.X;
NewRot->s.Y = Perp.s.Y;
NewRot->s.Z = Perp.s.Z;
//In the quaternion values, w is cosine (theta / 2), where theta is rotation angle
NewRot->s.W= Vector3fDot(&this->StVec, &this->EnVec);
}
else //if its zero
{
//The begin and end vectors coincide, so return an identity transform
NewRot->s.X =
NewRot->s.Y =
NewRot->s.Z =
NewRot->s.W = 0.0f;
}
}
}
//Mouse drag, calculate rotation
inline void ArcBallDrag(ArcBall_t *a, double x, double y, Quat4fT* NewRot) {
//Map the point to the sphere
ArcBallMapToSphere(a, x, y, &(a->EnVec));
//Return the quaternion equivalent to the rotation
if (NewRot) {
Vector3fT Perp;
//Compute the vector perpendicular to the begin and end vectors
Vector3fCross(&Perp, &(a->StVec), &(a->EnVec));
//Compute the length of the perpendicular vector
if (Vector3fLength(&Perp) > ArcBallEpsilon) { //if its non-zero
//We're ok, so return the perpendicular vector as the transform after all
NewRot->s.X = Perp.s.X;
NewRot->s.Y = Perp.s.Y;
NewRot->s.Z = Perp.s.Z;
//In the quaternion values, w is cosine (theta / 2), where theta is rotation angle
NewRot->s.W= Vector3fDot(&(a->StVec), &(a->EnVec));
} else { //if its zero
//The begin and end vectors coincide, so return an identity transform
NewRot->s.X = 0.0f;
NewRot->s.Y = 0.0f;
NewRot->s.Z = 0.0f;
NewRot->s.W = 0.0f;
}
}
}
/**
* The normal vector, unnormalised.
*/
static Vector3f TriangleNormalV
(
const Triangle* pT
)
{
const Vector3f edge1 = Vector3fSub( &pT->aVertexs[1], &pT->aVertexs[0] );
const Vector3f edge3 = Vector3fSub( &pT->aVertexs[2], &pT->aVertexs[1] );
return Vector3fCross( &edge1, &edge3 );
}
void Objects::timber4(float width, float fromX, float fromY, float toX, float toY) {
float ir=width/(float)2;
Tuple3fT a; a.s.X=fromX-toX; a.s.Y=fromY-toY; a.s.Z=0;
Tuple3fT b; b.s.X=0; b.s.Y=0; b.s.Z=-1;
Tuple3fT normal, dir;
Vector3fCross(&normal, &a, &b);
GLfloat l=Vector3fLength(&normal);
normal.s.X=normal.s.X/l; normal.s.Y=normal.s.Y/l; normal.s.Z=normal.s.Z/l;
dir.s.X=normal.s.X*ir; dir.s.Y=normal.s.Y*ir; dir.s.Z=normal.s.Z*ir;
l=Vector3fLength(&a);
a.s.X=a.s.X/l; a.s.Y=a.s.Y/l; a.s.Z=a.s.Z/l;
glBegin(GL_TRIANGLES);
// If it's too slow, leave these 4 triangles away
// 4 triangles to model the two caps
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,-ir);
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,ir);
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,ir);
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,-ir);
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,-ir);
glNormal3f(a.s.X,a.s.Y,a.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,-ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,-ir);
glNormal3f(-a.s.X,-a.s.Y,-a.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,-ir);
// 4 triangles for 2 sides
glNormal3f(0,0,1);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,ir);
glNormal3f(0,0,1);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,ir);
glNormal3f(0,0,1);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,ir);
glNormal3f(0,0,1);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,ir);
glNormal3f(0,0,1);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,ir);
glNormal3f(0,0,1);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,ir);
glNormal3f(0,0,-1);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,-ir);
glNormal3f(0,0,-1);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,-ir);
glNormal3f(0,0,-1);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,-ir);
glNormal3f(0,0,-1);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,-ir);
glNormal3f(0,0,-1);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,-ir);
glNormal3f(0,0,-1);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,-ir);
// Schiefe Ebene
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,-ir);
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,ir);
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,ir);
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(fromX-dir.s.X,fromY-dir.s.Y,-ir);
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,ir);
glNormal3f(-normal.s.X,-normal.s.Y,-normal.s.Z);
glVertex3f(toX-dir.s.X,toY-dir.s.Y,-ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,-ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(fromX+dir.s.X,fromY+dir.s.Y,-ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,ir);
glNormal3f(normal.s.X,normal.s.Y,normal.s.Z);
glVertex3f(toX+dir.s.X,toY+dir.s.Y,-ir);
glEnd();
}
