def polygon_clip_unnest()

in utils/box_ops3d.py [0:0]

• 21 lines of code
• 8 McCabe index (conditional complexity)

def polygon_clip_unnest(subjectPolygon: torch.Tensor, clipPolygon: torch.Tensor):
    """ Clip a polygon with another polygon.

   Ref: https://rosettacode.org/wiki/Sutherland-Hodgman_polygon_clipping#Python

   Args:
     subjectPolygon: a list of (x,y) 2d points, any polygon.
     clipPolygon: a list of (x,y) 2d points, has to be *convex*
   Note:
     **points have to be counter-clockwise ordered**

   Return:
     a list of (x,y) vertex point for the intersection polygon.
   """
    outputList = [subjectPolygon[x] for x in range(subjectPolygon.shape[0])]
    cp1 = clipPolygon[-1]

    for clipVertex in clipPolygon:
        cp2 = clipVertex
        inputList = outputList.copy()
        outputList.clear()
        s = inputList[-1]
 
        for subjectVertex in inputList:
            e = subjectVertex
            if helper_inside(cp1, cp2, e):
                if not helper_inside(cp1, cp2, s):
                    outputList.append(helper_computeIntersection(cp1, cp2, s, e))
                outputList.append(e)
            elif helper_inside(cp1, cp2, s):
                outputList.append(helper_computeIntersection(cp1, cp2, s, e))
            s = e
        cp1 = cp2
        if len(outputList) == 0:
            # return None
            break
    return outputList