public static DistanceType CheckDistances(Tri tri1, Tri tri2)
{
//plane equation: p2 = normal2 * X + d2
float distance1 = Vector3.Dot(tri2.normal, tri1.v0) + tri2.d;
float distance2 = Vector3.Dot(tri2.normal, tri1.v1) + tri2.d;
float distance3 = Vector3.Dot(tri2.normal, tri1.v2) + tri2.d;
if (Math.Abs(distance1) > float.Epsilon &&
Math.Abs(distance2) > float.Epsilon &&
Math.Abs(distance3) > float.Epsilon)
{
if ((distance1 < 0 && distance2 < 0 && distance3 < 0)
||
(distance1 > 0 && distance2 > 0 && distance3 > 0))
{
return(DistanceType.NON_ZERO_SAME_SIGN);
}
else
{
return(DistanceType.NON_ZERO_DIFFERENT_SIGN);
}
}
else
{
return(DistanceType.ZERO);
}
}
static void Main(string[] args)
{
Tri tri1 = new Tri(new float[9] {
0, 10, 20, 60, 60, 60, 10, 10, 60
});
Tri tri2 = new Tri(new float[9] {
0, 0, 20, 60, -60, 60, 10, -10, 60
});
var isIntersect = TriTriOverlap.IsTriTriIntersect(tri1, tri2);
Console.WriteLine("isIntersect: " + isIntersect);
tri1 = new Tri(new float[9] {
0, 10, 20, 60, 60, 60, 10, 10, 60
});
tri2 = new Tri(new float[9] {
0, 20, 20, 60, -60, 60, 10, -10, 60
});
isIntersect = TriTriOverlap.IsTriTriIntersect(tri1, tri2);
Console.WriteLine("isIntersect: " + isIntersect);
tri1 = new Tri(new float[9] {
-20, -20, 0, 20, 20, 20, -10, -10, 20,
});
tri2 = new Tri(new float[9] {
20, -30, 0, 30, 30, 10, -15, -15, 25
});
isIntersect = TriTriOverlap.IsTriTriIntersect(tri1, tri2);
Console.WriteLine("isIntersect: " + isIntersect);
// var triPoints_modelSpace = [
//0, 10, 20, 60, 60, 60, 10, 10, 60,
//0, 20, 20, 60, -60, 60, 10, -10, 60]
}
public static bool IsTriTriIntersect(Tri tri1, Tri tri2)
{
var distanceTri1_2 = CheckDistances(tri1, tri2);
if (distanceTri1_2 == DistanceType.NON_ZERO_SAME_SIGN)
{
return(false);
}
var distanceTri2_1 = CheckDistances(tri2, tri1);
if (distanceTri2_1 == DistanceType.NON_ZERO_SAME_SIGN)
{
return(false);
}
if (distanceTri1_2 == DistanceType.ZERO || distanceTri2_1 == DistanceType.ZERO)
{
return(IsCoplanarIntersect(tri1, tri2));
}
var L_intersectLine = Vector3.Cross(tri1.normal, tri2.normal);
var max = Math.Abs(L_intersectLine.X);
var index = 0;
var bb = Math.Abs(L_intersectLine.Y);
var cc = Math.Abs(L_intersectLine.Z);
if (bb > max)
{
max = bb; index = 1;
}
if (cc > max)
{
max = cc; index = 2;
}
float vp0, vp1, vp2, up0, up1, up2;
vp0 = tri1.v0.ElemByIndex(index);
vp1 = tri1.v1.ElemByIndex(index);
vp2 = tri1.v2.ElemByIndex(index);
up0 = tri2.v0.ElemByIndex(index);
up1 = tri2.v1.ElemByIndex(index);
up2 = tri2.v2.ElemByIndex(index);
// compute interval for triangle 1
float a = 0, b = 0, c = 0, x0 = 0, x1 = 0;
float dv0 = Vector3.Dot(tri2.normal, tri1.v0) + tri2.d;
float dv1 = Vector3.Dot(tri2.normal, tri1.v1) + tri2.d;
float dv2 = Vector3.Dot(tri2.normal, tri1.v2) + tri2.d;
float dv0dv1 = dv0 * dv1;
float dv0dv2 = dv0 * dv2;
if (ComputeIntervals(vp0, vp1, vp2, dv0, dv1, dv2, dv0dv1, dv0dv2, ref a, ref b, ref c, ref x0, ref x1))
{
return(false);
//return TriTriCoplanar(n1, v0, v1, v2, u0, u1, u2);
}
// compute interval for triangle 1
float du0 = Vector3.Dot(tri1.normal, tri2.v0) + tri1.d;
float du1 = Vector3.Dot(tri1.normal, tri2.v1) + tri1.d;
float du2 = Vector3.Dot(tri1.normal, tri2.v2) + tri1.d;
float du0du1 = du0 * du1;
float du0du2 = du0 * du2;
// compute interval for triangle 2
float d = 0, e = 0, f = 0, y0 = 0, y1 = 0;
if (ComputeIntervals(up0, up1, up2, du0, du1, du2, du0du1, du0du2, ref d, ref e, ref f, ref y0, ref y1))
{
return(false);
//return TriTriCoplanar(n1, v0, v1, v2, u0, u1, u2);
}
float xx, yy, xxyy, tmp;
xx = x0 * x1;
yy = y0 * y1;
xxyy = xx * yy;
tmp = a * xxyy;
Vector2 isect1 = Vector2.Zero, isect2 = Vector2.Zero;
isect1.X = tmp + b * x1 * yy;
isect1.Y = tmp + c * x0 * yy;
tmp = d * xxyy;
isect2.X = tmp + e * xx * y1;
isect2.Y = tmp + f * xx * y0;
Sort(isect1);
Sort(isect2);
return(!(isect1.Y < isect2.X || isect2.Y < isect1.X));
}
public static bool IsCoplanarIntersect(Tri tri1, Tri tri2)
{
return(true);
}
