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Diffstat (limited to 'silx/gui/_glutils/utils.py')
| -rw-r--r-- | silx/gui/_glutils/utils.py | 73 |
1 files changed, 72 insertions, 1 deletions
diff --git a/silx/gui/_glutils/utils.py b/silx/gui/_glutils/utils.py index 73af338..35cf819 100644 --- a/silx/gui/_glutils/utils.py +++ b/silx/gui/_glutils/utils.py @@ -1,7 +1,7 @@ # coding: utf-8 # /*########################################################################## # -# Copyright (c) 2014-2017 European Synchrotron Radiation Facility +# Copyright (c) 2014-2019 European Synchrotron Radiation Facility # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal @@ -68,3 +68,74 @@ def isSupportedGLType(type_): def numpyToGLType(type_): """Returns the GL type corresponding the provided numpy type or dtype.""" return _TYPE_CONVERTER[numpy.dtype(type_)] + + +def segmentTrianglesIntersection(segment, triangles): + """Check for segment/triangles intersection. + + This is based on signed tetrahedron volume comparison. + + See A. Kensler, A., Shirley, P. + Optimizing Ray-Triangle Intersection via Automated Search. + Symposium on Interactive Ray Tracing, vol. 0, p33-38 (2006) + + :param numpy.ndarray segment: + Segment end points as a 2x3 array of coordinates + :param numpy.ndarray triangles: + Nx3x3 array of triangles + :return: (triangle indices, segment parameter, barycentric coord) + Indices of intersected triangles, "depth" along the segment + of the intersection point and barycentric coordinates of intersection + point in the triangle. + :rtype: List[numpy.ndarray] + """ + # TODO triangles from vertices + indices + # TODO early rejection? e.g., check segment bbox vs triangle bbox + segment = numpy.asarray(segment) + assert segment.ndim == 2 + assert segment.shape == (2, 3) + + triangles = numpy.asarray(triangles) + assert triangles.ndim == 3 + assert triangles.shape[1] == 3 + + # Test line/triangles intersection + d = segment[1] - segment[0] + t0s0 = segment[0] - triangles[:, 0, :] + edge01 = triangles[:, 1, :] - triangles[:, 0, :] + edge02 = triangles[:, 2, :] - triangles[:, 0, :] + + dCrossEdge02 = numpy.cross(d, edge02) + t0s0CrossEdge01 = numpy.cross(t0s0, edge01) + volume = numpy.sum(dCrossEdge02 * edge01, axis=1) + del edge01 + subVolumes = numpy.empty((len(triangles), 3), dtype=triangles.dtype) + subVolumes[:, 1] = numpy.sum(dCrossEdge02 * t0s0, axis=1) + del dCrossEdge02 + subVolumes[:, 2] = numpy.sum(t0s0CrossEdge01 * d, axis=1) + subVolumes[:, 0] = volume - subVolumes[:, 1] - subVolumes[:, 2] + intersect = numpy.logical_or( + numpy.all(subVolumes >= 0., axis=1), # All positive + numpy.all(subVolumes <= 0., axis=1)) # All negative + intersect = numpy.where(intersect)[0] # Indices of intersected triangles + + # Get barycentric coordinates + barycentric = subVolumes[intersect] / volume[intersect].reshape(-1, 1) + del subVolumes + + # Test segment/triangles intersection + volAlpha = numpy.sum(t0s0CrossEdge01[intersect] * edge02[intersect], axis=1) + t = volAlpha / volume[intersect] # segment parameter of intersected triangles + del t0s0CrossEdge01 + del edge02 + del volAlpha + del volume + + inSegmentMask = numpy.logical_and(t >= 0., t <= 1.) + intersect = intersect[inSegmentMask] + t = t[inSegmentMask] + barycentric = barycentric[inSegmentMask] + + # Sort intersecting triangles by t + indices = numpy.argsort(t) + return intersect[indices], t[indices], barycentric[indices] |