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Use the true triangle face normal if contact is not on an edge in smooth triangle contact

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This commit is contained in:
Daniel Chappuis 2017-11-10 17:51:02 +01:00
parent de95e15147
commit 222636391e
1 changed files with 10 additions and 1 deletions
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11
src/collision/shapes/TriangleShape.cpp
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@ -133,13 +133,22 @@ void TriangleShape::computeSmoothMeshContact(Vector3 localContactPointTriangle,
/// normal of the mesh at this point. The idea to solve this problem is to use the real (smooth) surface /// normal of the mesh at this point. The idea to solve this problem is to use the real (smooth) surface
/// normal of the mesh at this point as the contact normal. This technique is described in the chapter 5 /// normal of the mesh at this point as the contact normal. This technique is described in the chapter 5
/// of the Game Physics Pearl book by Gino van der Bergen and Dirk Gregorius. The vertices normals of the /// of the Game Physics Pearl book by Gino van der Bergen and Dirk Gregorius. The vertices normals of the
/// mesh are either provided by the user or precomputed if the user did not provide them. /// mesh are either provided by the user or precomputed if the user did not provide them. Note that we only
/// use the interpolated normal if the contact point is on an edge of the triangle. If the contact is in the
/// middle of the triangle, we return the true triangle normal.
Vector3 TriangleShape::computeSmoothLocalContactNormalForTriangle(const Vector3& localContactPoint) const { Vector3 TriangleShape::computeSmoothLocalContactNormalForTriangle(const Vector3& localContactPoint) const {
// Compute the barycentric coordinates of the point in the triangle // Compute the barycentric coordinates of the point in the triangle
decimal u, v, w; decimal u, v, w;
computeBarycentricCoordinatesInTriangle(mPoints[0], mPoints[1], mPoints[2], localContactPoint, u, v, w); computeBarycentricCoordinatesInTriangle(mPoints[0], mPoints[1], mPoints[2], localContactPoint, u, v, w);
// If the contact is in the middle of the triangle face (not on the edges)
if (u > MACHINE_EPSILON && v > MACHINE_EPSILON && w > MACHINE_EPSILON) {
// We return the true triangle face normal (not the interpolated one)
return mNormal;
}
// We compute the contact normal as the barycentric interpolation of the three vertices normals // We compute the contact normal as the barycentric interpolation of the three vertices normals
return (u * mVerticesNormals[0] + v * mVerticesNormals[1] + w * mVerticesNormals[2]).getUnit(); return (u * mVerticesNormals[0] + v * mVerticesNormals[1] + w * mVerticesNormals[2]).getUnit();
} }