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Deduplicate triangle-triangle intersection code #86

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8902ea6
Deduplicate triangle-triangle intersection code
Garrett-R Dec 2, 2018
3bde551
Add to Projects using g3Sharp in README
Garrett-R Dec 2, 2018
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1 change: 1 addition & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ Questions? Contact Ryan Schmidt [@rms80](http://www.twitter.com/rms80) / [gradie
* [Nia Technologies NiaFit](https://niatech.org/technology/niafit/) - 3D-printed prosthetic and orthotic design
* [OrthoVR Project](https://orthovrproject.org/) - 3D-printed lower-leg prosthetic design in VR
* [Archform](https://www.archform.co/) - Clear Dental Aligner design/planning app
* [UpCodes AI](https://up.codes/features/ai) - Building code automation plugin
* [Your Project Here?]([email protected]) - *we are very excited to hear about your project!*


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102 changes: 11 additions & 91 deletions intersection/IntrTriangle3Triangle3.cs
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Expand Up @@ -149,100 +149,16 @@ public bool Find()
return false;
}


public bool Test()
{
// Get edge vectors for triangle0.
Vector3dTuple3 E0;
E0.V0 = triangle0.V1 - triangle0.V0;
E0.V1 = triangle0.V2 - triangle0.V1;
E0.V2 = triangle0.V0 - triangle0.V2;

// Get normal vector of triangle0.
Vector3d N0 = E0[0].UnitCross(E0[1]);

// Project triangle1 onto normal line of triangle0, test for separation.
double N0dT0V0 = N0.Dot(triangle0.V0);
double min1, max1;
ProjectOntoAxis(ref triangle1, ref N0, out min1, out max1);
if (N0dT0V0 < min1 || N0dT0V0 > max1) {
return false;
}

// Get edge vectors for triangle1.
Vector3dTuple3 E1;
E1.V0 = triangle1.V1 - triangle1.V0;
E1.V1 = triangle1.V2 - triangle1.V1;
E1.V2 = triangle1.V0 - triangle1.V2;

// Get normal vector of triangle1.
Vector3d N1 = E1[0].UnitCross(E1[1]);

Vector3d dir;
double min0, max0;
int i0, i1;

Vector3d N0xN1 = N0.UnitCross(N1);
if (N0xN1.Dot(N0xN1) >= MathUtil.ZeroTolerance) {
// Triangles are not parallel.

// Project triangle0 onto normal line of triangle1, test for
// separation.
double N1dT1V0 = N1.Dot(triangle1.V0);
ProjectOntoAxis(ref triangle0, ref N1, out min0, out max0);
if (N1dT1V0 < min0 || N1dT1V0 > max0) {
return false;
}

// Directions E0[i0]xE1[i1].
for (i1 = 0; i1 < 3; ++i1) {
for (i0 = 0; i0 < 3; ++i0) {
dir = E0[i0].UnitCross(E1[i1]);
ProjectOntoAxis(ref triangle0, ref dir, out min0, out max0);
ProjectOntoAxis(ref triangle1, ref dir, out min1, out max1);
if (max0 < min1 || max1 < min0) {
return false;
}
}
}

// The test query does not know the intersection set.
Type = IntersectionType.Unknown;
} else { // Triangles are parallel (and, in fact, coplanar).
// Directions N0xE0[i0].
for (i0 = 0; i0 < 3; ++i0) {
dir = N0.UnitCross(E0[i0]);
ProjectOntoAxis(ref triangle0, ref dir, out min0, out max0);
ProjectOntoAxis(ref triangle1, ref dir, out min1, out max1);
if (max0 < min1 || max1 < min0) {
return false;
}
}

// Directions N1xE1[i1].
for (i1 = 0; i1 < 3; ++i1) {
dir = N1.UnitCross(E1[i1]);
ProjectOntoAxis(ref triangle0, ref dir, out min0, out max0);
ProjectOntoAxis(ref triangle1, ref dir, out min1, out max1);
if (max0 < min1 || max1 < min0) {
return false;
}
}

// The test query does not know the intersection set.
Type = IntersectionType.Plane;
}

return true;
public bool Test() {
return Intersects(ref triangle0, ref triangle1, ref Type);
}

public static bool Intersects(ref Triangle3d triangle0, ref Triangle3d triangle1) {
IntersectionType dummy = 0;
return Intersects(ref triangle0, ref triangle1, ref dummy);
}






public static bool Intersects(ref Triangle3d triangle0, ref Triangle3d triangle1)
private static bool Intersects(ref Triangle3d triangle0, ref Triangle3d triangle1, ref IntersectionType type)
{
// Get edge vectors for triangle0.
Vector3dTuple3 E0;
Expand Down Expand Up @@ -298,6 +214,8 @@ public static bool Intersects(ref Triangle3d triangle0, ref Triangle3d triangle1
}
}

// The test query does not know the intersection set.
type = IntersectionType.Unknown;
} else { // Triangles are parallel (and, in fact, coplanar).
// Directions N0xE0[i0].
for (i0 = 0; i0 < 3; ++i0) {
Expand All @@ -318,6 +236,8 @@ public static bool Intersects(ref Triangle3d triangle0, ref Triangle3d triangle1
return false;
}
}
// The test query does not know the intersection set.
type = IntersectionType.Plane;
}

return true;
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