// Real-time Collision Detection, p179.
public float RayCast(Vector3 from, Vector3 to, float maxFraction = 1.0f)
{
float tMin = float.MinValue;
float tMax = float.MaxValue;
Vector3 d = to - from;
Vector3 absD = VectorUtil.Abs(d);
for (int i = 0; i < 3; ++i)
{
float dComp = VectorUtil.GetComopnent(d, i);
float absDComp = VectorUtil.GetComopnent(absD, i);
float fromComp = VectorUtil.GetComopnent(from, i);
float minComp = VectorUtil.GetComopnent(Min, i);
float maxComp = VectorUtil.GetComopnent(Max, i);
if (absDComp < float.Epsilon)
{
// parallel?
if (fromComp < minComp || maxComp < fromComp)
{
return(float.MinValue);
}
}
else
{
float invD = 1.0f / dComp;
float t1 = (minComp - fromComp) * invD;
float t2 = (maxComp - fromComp) * invD;
if (t1 > t2)
{
float temp = t1;
t1 = t2;
t2 = temp;
}
tMin = Mathf.Max(tMin, t1);
tMax = Mathf.Min(tMax, t2);
if (tMin > tMax)
{
return(float.MinValue);
}
}
}
// does the ray start inside the box?
// does the ray intersect beyond the max fraction?
if (tMin < 0.0f || maxFraction < tMin)
{
return(float.MinValue);
}
// intersection detected
return(tMin);
}
private static Vector3 Quantize(Vector3 v, float step)
{
Vector3 s = new Vector3(Mathf.Sign(v.x), Mathf.Sign(v.y), Mathf.Sign(v.z));
v += 0.125f * step * Vector3.one;
v = VectorUtil.CompDiv(v, 0.25f * step * Vector3.one);
v = VectorUtil.Abs(v);
v = new Vector3(Mathf.Floor(v.x), Mathf.Floor(v.y), Mathf.Floor(v.z));
v = VectorUtil.CompMul(s, v);
return(v);
}
public Aabb BoundaryShapeBounds(SdfBrush.BoundaryShapeEnum boundaryShape, float radius)
{
Vector3 size = transform.localScale;
Aabb bounds = Aabb.Empty;
switch (boundaryShape)
{
case SdfBrush.BoundaryShapeEnum.Box:
{
Vector3 r = 0.5f * size;
bounds = new Aabb(-r, r);
bounds.Rotate(RotationRs(transform.rotation));
break;
}
case SdfBrush.BoundaryShapeEnum.Sphere:
{
Vector3 r = radius * size;
bounds = new Aabb(-r, r);
bounds.Rotate(RotationRs(transform.rotation));
break;
}
case SdfBrush.BoundaryShapeEnum.Cylinder:
{
Vector3 r = new Vector3(radius, 0.5f * size.y, radius);
bounds = new Aabb(-r, r);
bounds.Rotate(RotationRs(transform.rotation));
break;
}
case SdfBrush.BoundaryShapeEnum.Torus:
{
Vector3 r = new Vector3(0.5f * size.x, 0.0f, 0.5f * size.z);
bounds = new Aabb(-r, r);
bounds.Rotate(RotationRs(transform.rotation));
Vector3 round = radius * Vector3.one;
bounds.Min -= round;
bounds.Max += round;
break;
}
case SdfBrush.BoundaryShapeEnum.SolidAngle:
{
Vector3 r = radius * VectorUtil.Abs(transform.localScale);
bounds = new Aabb(-r, r);
break;
}
}
return(bounds);
}
public void Rotate(Quaternion q)
{
Vector3 oldExtentsA = Extent;
Vector3 newExtents = oldExtentsA;
newExtents = VectorUtil.Max(newExtents, VectorUtil.Abs(q * new Vector3(oldExtentsA.x, oldExtentsA.y, oldExtentsA.z)));
newExtents = VectorUtil.Max(newExtents, VectorUtil.Abs(q * new Vector3(-oldExtentsA.x, oldExtentsA.y, oldExtentsA.z)));
newExtents = VectorUtil.Max(newExtents, VectorUtil.Abs(q * new Vector3(oldExtentsA.x, -oldExtentsA.y, oldExtentsA.z)));
newExtents = VectorUtil.Max(newExtents, VectorUtil.Abs(q * new Vector3(oldExtentsA.x, oldExtentsA.y, -oldExtentsA.z)));
Vector3 newCenter = q * Center;
Min = newCenter - newExtents;
Max = newCenter + newExtents;
}
