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add a function to find barycentric coordinates wrt. triangle

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This commit is contained in:
Irlan 2018-03-28 01:22:09 -03:00
parent cc425786bc
commit 8c2df2f70c
1 changed files with 27 additions and 0 deletions
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27
include/bounce/common/geometry.h
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@ -99,6 +99,33 @@ inline void b3BarycentricCoordinates(float32 out[3],
out[1] = -b3Dot(QA, AB); out[1] = -b3Dot(QA, AB);
out[2] = divisor; out[2] = divisor;
} }
// Convert a point Q from Cartesian coordinates to Barycentric coordinates (u, v, w)
// with respect to a triangle ABC.
// The last output value is the divisor.
inline void b3BarycentricCoordinates(float32 out[4],
const b3Vec3& A, const b3Vec3& B, const b3Vec3& C,
const b3Vec3& Q)
{
b3Vec3 AB = B - A;
b3Vec3 AC = C - A;
b3Vec3 QA = A - Q;
b3Vec3 QB = B - Q;
b3Vec3 QC = C - Q;
b3Vec3 QB_x_QC = b3Cross(QB, QC);
b3Vec3 QC_x_QA = b3Cross(QC, QA);
b3Vec3 QA_x_QB = b3Cross(QA, QB);
b3Vec3 AB_x_AC = b3Cross(AB, AC);
//float32 divisor = b3Dot(AB_x_AC, AB_x_AC);
out[0] = b3Dot(QB_x_QC, AB_x_AC);
out[1] = b3Dot(QC_x_QA, AB_x_AC);
out[2] = b3Dot(QA_x_QB, AB_x_AC);
out[3] = out[0] + out[1] + out[2];
}
// Project a point onto a segment AB. // Project a point onto a segment AB.
inline b3Vec3 b3ClosestPointOnSegment(const b3Vec3& P, const b3Vec3& A, const b3Vec3& B) inline b3Vec3 b3ClosestPointOnSegment(const b3Vec3& P, const b3Vec3& A, const b3Vec3& B)