protected double intersectsAt(
Plane plane, double effectiveRadius, Vec4 endpoint1, Vec4 endpoint2) {
// Test the distance from the first end-point.
double dq1 = plane.dot(endpoint1);
boolean bq1 = dq1 <= -effectiveRadius;
// Test the distance from the possibly reduced second end-point.
double dq2 = plane.dot(endpoint2);
boolean bq2 = dq2 <= -effectiveRadius;
if (bq1
&& bq2) // endpoints more distant from plane than effective radius; box is on neg. side of
// plane
return -1;
if (bq1 == bq2) // endpoints less distant from plane than effective radius; can't draw any
// conclusions
return 0;
// Compute and return the endpoints of the cylinder on the positive side of the plane.
this.tmp3.subtract3AndSet(endpoint1, endpoint2);
double t = (effectiveRadius + dq1) / plane.getNormal().dot3(this.tmp3);
this.tmp3.subtract3AndSet(endpoint2, endpoint1).multiply3AndSet(t).add3AndSet(endpoint1);
// truncate the line to only that in the positive halfspace (e.g., inside the frustum)
if (bq1) endpoint1.set(this.tmp3);
else endpoint2.set(this.tmp3);
return t;
}
/** {@inheritDoc} */
public double getEffectiveRadius(Plane plane) {
if (plane == null) return 0;
// Determine the effective radius of the box axis relative to the plane.
Vec4 n = plane.getNormal();
return 0.5 * (Math.abs(this.s.dot3(n)) + Math.abs(this.t.dot3(n)));
}
