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Add vantage point tree for searching vector lists. Add "concave"

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method to vnf_vertex_array.
This commit is contained in:
Adrian Mariano
2021-05-11 20:51:09 -04:00
parent a9cd600782
commit c4ace59ccd
3 changed files with 171 additions and 4 deletions
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16
vnf.scad
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@@ -221,8 +221,8 @@ function vnf_triangulate(vnf) =
// triangles. The default style is an arbitrary, systematic subdivision in the same direction. The "alt" style
// is the uniform subdivision in the other (alternate) direction. The "min_edge" style picks the shorter edge to
// subdivide for each quadrilateral, so the division may not be uniform across the shape. The "quincunx" style
// adds a vertex in the center of each quadrilateral and creates four triangles, and the "convex" style
// chooses the locally convex subdivision.
// adds a vertex in the center of each quadrilateral and creates four triangles, and the "convex" and "concave" styles
// chooses the locally convex/concave subdivision.
// Arguments:
// points = A list of vertices to divide into columns and rows.
// caps = If true, add endcap faces to the first AND last rows.
@@ -231,7 +231,7 @@ function vnf_triangulate(vnf) =
// col_wrap = If true, add faces to connect the last column to the first.
// row_wrap = If true, add faces to connect the last row to the first.
// reverse = If true, reverse all face normals.
// style = The style of subdividing the quads into faces. Valid options are "default", "alt", "min_edge", "quincunx", and "convex".
// style = The style of subdividing the quads into faces. Valid options are "default", "alt", "min_edge", "quincunx","convex" and "concave".
// vnf = If given, add all the vertices and faces to this existing VNF structure.
// Example(3D):
// vnf = vnf_vertex_array(
@@ -297,7 +297,7 @@ function vnf_vertex_array(
) =
assert(!(any([caps,cap1,cap2]) && !col_wrap), "col_wrap must be true if caps are requested")
assert(!(any([caps,cap1,cap2]) && row_wrap), "Cannot combine caps with row_wrap")
assert(in_list(style,["default","alt","quincunx", "convex","min_edge"]))
assert(in_list(style,["default","alt","quincunx", "convex","concave", "min_edge"]))
assert(is_consistent(points), "Non-rectangular or invalid point array")
let(
pts = flatten(points),
@@ -358,6 +358,14 @@ function vnf_vertex_array(
: [[i1,i3,i2],[i1,i4,i3]]
)
convexfaces
: style=="concave"?
let( // Find normal for 3 of the points. Is the other point above or below?
n = (reverse?-1:1)*cross(pts[i2]-pts[i1],pts[i3]-pts[i1]),
concavefaces = n==0 ? [[i1,i4,i3]]
: n*pts[i4] <= n*pts[i1] ? [[i1,i4,i2],[i2,i4,i3]]
: [[i1,i3,i2],[i1,i4,i3]]
)
concavefaces
: [[i1,i3,i2],[i1,i4,i3]],
// remove degenerate faces
culled_faces= [for(face=faces)