Fixed broken line-plane intersections. Attachment enhanced vnf_polyhedron().

attachments.scad

@@ -461,13 +461,16 @@ function find_anchor(anchor, geom) =
             rpts = apply(rot(from=anchor, to=RIGHT) * move(point3d(-cp)), points),
             hits = [
                 for (face = faces) let(
-                    verts = select(rpts, face)
+                    verts = select(rpts, face),
+                    xs = subindex(verts,0),
+                    ys = subindex(verts,1),
+                    zs = subindex(verts,2)
                 ) if (
-                    max(subindex(verts,0)) >= -eps &&
+                    max(xs) >= -eps &&
-                    max(subindex(verts,1)) >= -eps &&
+                    max(ys) >= -eps &&
-                    max(subindex(verts,2)) >= -eps &&
+                    max(zs) >= -eps &&
-                    min(subindex(verts,1)) <=  eps &&
+                    min(ys) <=  eps &&
-                    min(subindex(verts,2)) <=  eps
+                    min(zs) <=  eps
                 ) let(
                     poly = select(points, face),
                     pt = polygon_line_intersection(poly, [cp,cp+anchor], bounded=[true,false], eps=eps)

geometry.scad

@@ -1007,11 +1007,20 @@ function closest_point_on_plane(plane, point) =
 // Returns [LINE, undef] if the line is on the plane.
 // Returns undef if line is parallel to, but not on the given plane.
 function _general_plane_line_intersection(plane, line, eps=EPSILON) =
-    let( a = plane*[each line[0],-1],
+    let(
-         b = plane*[each(line[1]-line[0]),-1] )
+        l0 = line[0],  // Ray start point
-    approx(b,0,eps) 
+        u = line[1] - l0,  // Ray direction vector
-    ? points_on_plane(line[0],plane,eps)? [line,undef]: undef
+        n = plane_normal(plane),
-    : [ line[0]+a/b*(line[1]-line[0]), a/b ];
+        p0 = n * plane[3],  // A point on the plane
+        w = l0 - p0  // Vector from plane point to ray start
+    ) approx(n*u, 0, eps=eps) ? (
+        // Line is parallel to plane.
+        approx(n*w, 0, eps=eps)
+          ? [line, undef] // Line is on the plane.
+          : undef // Line never intersects the plane.
+    ) : let(
+        t = (-n * w) / (n * u)  // Distance ratio along ray
+    ) [ l0 + u*t, t ];
 
 
 // Function: plane_line_angle()
@@ -1098,8 +1107,8 @@ function polygon_line_intersection(poly, line, bounded=false, eps=EPSILON) =
             linevec = unit(line[1] - line[0]),
             lp1 = line[0] + (bounded[0]? 0 : -1000000) * linevec,
             lp2 = line[1] + (bounded[1]? 0 :  1000000) * linevec,
-            poly2d = clockwise_polygon(project_plane(poly, p1, p2, p3)),
+            poly2d = clockwise_polygon(project_plane(poly, plane)),
-            line2d = project_plane([lp1,lp2], p1, p2, p3),
+            line2d = project_plane([lp1,lp2], plane),
             parts = split_path_at_region_crossings(line2d, [poly2d], closed=false),
             inside = [for (part = parts)
                           if (point_in_polygon(mean(part), poly2d)>0) part
@@ -1107,7 +1116,7 @@ function polygon_line_intersection(poly, line, bounded=false, eps=EPSILON) =
         ) 
         !inside? undef :
         let(
-            isegs = [for (seg = inside) lift_plane(seg, p1, p2, p3) ]
+            isegs = [for (seg = inside) lift_plane(seg, plane) ]
         ) 
         isegs
     ) 
@@ -1264,7 +1273,6 @@ function find_circle_2tangents(pt1, pt2, pt3, r, d, tangents=false) =
             x = hyp * cos(a/2),
             tp1 = pt2 + x * v1,
             tp2 = pt2 + x * v2,
-//            fff=echo(tp1=tp1,cp=cp,pt2=pt2),
             dang1 = vector_angle(tp1-cp,pt2-cp),
             dang2 = vector_angle(tp2-cp,pt2-cp)
             ) 

tests/test_geometry.scad

@@ -53,7 +53,7 @@ test_tri_functions();
 //test__general_plane_line_intersection();
 //test_plane_line_angle();
 //test_plane_line_intersection();
-//test_polygon_line_intersection();
+test_polygon_line_intersection();
 //test_plane_intersection();
 test_coplanar();
 test_points_on_plane();
@@ -542,6 +542,17 @@ module test_distance_from_plane() {
 *test_distance_from_plane();
 
 
+module test_polygon_line_intersection() {
+    poly1 = [[50,50,50], [50,-50,50], [-50,-50,50]];
+    assert_approx(polygon_line_intersection(poly1, [CENTER, UP]), [0,0,50]);
+    assert_approx(polygon_line_intersection(poly1, [CENTER, UP+RIGHT]), [50,0,50]);
+    assert_approx(polygon_line_intersection(poly1, [CENTER, UP+BACK+RIGHT]), [50,50,50]);
+    assert_approx(polygon_line_intersection(poly1, [[0,0,50], [1,0,50]]), [[[0,0,50], [50,0,50]]]);
+    assert_approx(polygon_line_intersection(poly1, [[0,0,0], [1,0,0]]), undef);
+}
+*test_polygon_line_intersection();
+
+
 module test_coplanar() {
     assert(coplanar([ [5,5,1],[0,0,1],[-1,-1,1] ]) == false);
     assert(coplanar([ [5,5,1],[0,0,0],[-1,-1,1] ]) == true);

version.scad

@@ -8,7 +8,7 @@
 //////////////////////////////////////////////////////////////////////
 
 
-BOSL_VERSION = [2,0,413];
+BOSL_VERSION = [2,0,414];
 
 
 // Section: BOSL Library Version Functions

vnf.scad

@@ -341,9 +341,17 @@ function vnf_vertex_array(
 // Arguments:
 //   vnf = A VNF structure, or list of VNF structures.
 //   convexity = Max number of times a line could intersect a wall of the shape.
-module vnf_polyhedron(vnf, convexity=2) {
+//   extent = If true, calculate anchors by extents, rather than intersection.  Default: true.
+//   cp = Centerpoint of VNF to use for anchoring when `extent` is false.  Default: `[0, 0, 0]`
+//   anchor = Translate so anchor point is at origin (0,0,0).  See [anchor](attachments.scad#anchor).  Default: `"origin"`
+//   spin = Rotate this many degrees around the Z axis after anchor.  See [spin](attachments.scad#spin).  Default: `0`
+//   orient = Vector to rotate top towards, after spin.  See [orient](attachments.scad#orient).  Default: `UP`
+module vnf_polyhedron(vnf, convexity=2, extent=true, cp=[0,0,0], anchor="origin", spin=0, orient=UP) {
     vnf = is_vnf_list(vnf)? vnf_merge(vnf) : vnf;
-    polyhedron(vnf[0], vnf[1], convexity=convexity);
+    attachable(anchor,spin,orient, vnf=vnf, cp=cp, extent=extent) {
+        polyhedron(vnf[0], vnf[1], convexity=convexity);
+        children();
+    }
 }