From f736ef98f76cdf566ce252816f8eeef3268b7758 Mon Sep 17 00:00:00 2001 From: Adrian Mariano Date: Fri, 5 Mar 2021 16:35:41 -0500 Subject: [PATCH] same_shape bugfix (fails if b==undef) check for collinear points in round_corners plus other fixes fix path_cut to work correctly when closed==true, and change it to fail with error when cut is too long instead of returning undef. Add path_cut_segs. --- common.scad | 2 +- paths.scad | 96 +++++++++++++++++++++++++++++++++--------- rounding.scad | 23 +++++++--- tests/test_common.scad | 6 +++ 4 files changed, 98 insertions(+), 29 deletions(-) diff --git a/common.scad b/common.scad index e9e4504..44f1513 100644 --- a/common.scad +++ b/common.scad @@ -244,7 +244,7 @@ function _list_pattern(list) = // Example: // same_shape([3,[4,5]],[7,[3,4]]); // Returns true // same_shape([3,4,5], [7,[3,4]]); // Returns false -function same_shape(a,b) = _list_pattern(a) == b*0; +function same_shape(a,b) = is_def(b) && _list_pattern(a) == b*0; // Function: is_bool_list() diff --git a/paths.scad b/paths.scad index c870b62..d3b18da 100644 --- a/paths.scad +++ b/paths.scad @@ -1225,11 +1225,17 @@ module path_spread(path, n, spacing, sp=undef, rotate_children=true, closed=fals // Cuts a path at a list of distances from the first point in the path. Returns a list of the cut // points and indices of the next point in the path after that point. So for example, a return // value entry of [[2,3], 5] means that the cut point was [2,3] and the next point on the path after -// this point is path[5]. If the path is too short then path_cut returns undef. If you set +// this point is path[5]. If the path is too short then path_cut fails with an error. If you set // `direction` to true then `path_cut` will also return the tangent vector to the path and a normal // vector to the path. It tries to find a normal vector that is coplanar to the path near the cut // point. If this fails it will return a normal vector parallel to the xy plane. The output with // direction vectors will be `[point, next_index, tangent, normal]`. +// . +// If you give the very last point of the path as a cut point then the returned index will be +// one larger than the last index (so it will not be a valid index). If you use the closed +// option then the returned index will be equal to the path length for cuts along the closing +// path segment, and if you give a point equal to the path length you will get an +// index of len(path)+1 for the index. // // Arguments: // path = path to cut @@ -1246,8 +1252,10 @@ module path_spread(path, n, spacing, sp=undef, rotate_children=true, closed=fals function path_cut(path, dists, closed=false, direction=false) = let(long_enough = len(path) >= (closed ? 3 : 2)) assert(long_enough,len(path)<2 ? "Two points needed to define a path" : "Closed path must include three points") - !is_list(dists)? path_cut(path, [dists],closed, direction)[0] - : let(cuts = _path_cut(path,dists,closed)) + is_num(dists) ? path_cut(path, [dists],closed, direction)[0] : + assert(is_vector(dists)) + assert(list_increasing(dists), "Cut distances must be an increasing list") + let(cuts = _path_cut(path,dists,closed)) !direction ? cuts : let( @@ -1260,20 +1268,23 @@ function path_cut(path, dists, closed=false, direction=false) = function _path_cut(path, dists, closed=false, pind=0, dtotal=0, dind=0, result=[]) = dind == len(dists) ? result : let( - lastpt = len(result)>0? select(result,-1)[0] : [], - dpartial = len(result)==0? 0 : norm(lastpt-path[pind]), - nextpoint = dpartial > dists[dind]-dtotal? - [lerp(lastpt,path[pind], (dists[dind]-dtotal)/dpartial),pind] : - _path_cut_single(path, dists[dind]-dtotal-dpartial, closed, pind) - ) is_undef(nextpoint)? - concat(result, repeat(undef,len(dists)-dind)) : - _path_cut(path, dists, closed, nextpoint[1], dists[dind],dind+1, concat(result, [nextpoint])); + lastpt = len(result)==0? [] : select(result,-1)[0], // location of last cut point + dpartial = len(result)==0? 0 : norm(lastpt-select(path,pind)), // remaining length in segment + nextpoint = dists[dind] <= dpartial+dtotal // Do we have enough length left on the current segment? + ? [lerp(lastpt,select(path,pind),(dists[dind]-dtotal)/dpartial),pind] + : _path_cut_single(path, dists[dind]-dtotal-dpartial, closed, pind) + ) + _path_cut(path, dists, closed, nextpoint[1], dists[dind],dind+1, concat(result, [nextpoint])); + // Search for a single cut point in the path function _path_cut_single(path, dist, closed=false, ind=0, eps=1e-7) = - ind>=len(path)? undef : - ind==len(path)-1 && !closed? (dist dist ? + // If we get to the very end of the path (ind is last point or wraparound for closed case) then + // check if we are within epsilon of the final path point. If not we're out of path, so we fail + ind==len(path)-(closed?0:1) ? + assert(dist dist ? [lerp(path[ind],select(path,ind+1),dist/d), ind+1] : _path_cut_single(path, dist-d,closed, ind+1, eps); @@ -1307,18 +1318,61 @@ function _path_cuts_dir(path, cuts, closed=false, eps=1e-2) = zeros = path[0]*0, nextind = cuts[ind][1], nextpath = unit(select(path, nextind+1)-select(path, nextind),zeros), - thispath = unit(select(path, nextind) - path[nextind-1],zeros), - lastpath = unit(path[nextind-1] - select(path, nextind-2),zeros), + thispath = unit(select(path, nextind) - select(path,nextind-1),zeros), + lastpath = unit(select(path,nextind-1) - select(path, nextind-2),zeros), nextdir = nextind==len(path) && !closed? lastpath : - (nextind<=len(path)-2 || closed) && approx(cuts[ind][0], path[nextind],eps)? - unit(nextpath+thispath) : - (nextind>1 || closed) && approx(cuts[ind][0],path[nextind-1],eps)? - unit(thispath+lastpath) : - thispath + (nextind<=len(path)-2 || closed) && approx(cuts[ind][0], path[nextind],eps) + ? unit(nextpath+thispath) + : (nextind>1 || closed) && approx(cuts[ind][0],select(path,nextind-1),eps) + ? unit(thispath+lastpath) + : thispath ) nextdir ]; + +// Function: path_cut_segs() +// Usage: +// path_list = path_cut_segs(path, cutdist, ); +// Description: +// Given a list of distances in `cutdist`, cut the path into +// subpaths at those lengths, returning a list of paths. +// If the input path is closed then the final path will include the +// original starting point. The list of cut distances must be +// in ascending order. If you repeat a distance you will get an +// empty list in that position in the output. +// Arguments: +// path = path to cut +// cutdist = distance or list of distances where path is cut +// closed = set to true for a closed path. Default: false +function path_cut_segs(path,cutdist,closed) = + is_num(cutdist) ? path_cut_segs(path,[cutdist],closed) : + assert(is_vector(cutdist)) + assert(select(cutdist,-1)0, "Cut distances must be strictly positive") + let( + cutlist = path_cut(path,cutdist,closed=closed), + cuts = len(cutlist) + ) + [ + [ each slice(path,0,cutlist[0][1]), + if (!approx(cutlist[0][0], path[cutlist[0][1]-1])) cutlist[0][0] + ], + for(i=[0:1:cuts-2]) + cutlist[i][0]==cutlist[i+1][0] ? [] + : + [ if (!approx(cutlist[i][0], select(path,cutlist[i][1]))) cutlist[i][0], + each slice(path,cutlist[i][1], cutlist[i+1][1]), + if (!approx(cutlist[i+1][0], select(path,cutlist[i+1][1]-1))) cutlist[i+1][0], + ], + [ + if (!approx(cutlist[cuts-1][0], select(path,cutlist[cuts-1][1]))) cutlist[cuts-1][0], + each select(path,cutlist[cuts-1][1],closed ? 0 : -1) + ] + ]; + + + // Input `data` is a list that sums to an integer. // Returns rounded version of input data so that every // entry is rounded to an integer and the sum is the same as diff --git a/rounding.scad b/rounding.scad index abfe0ba..a6c1d14 100644 --- a/rounding.scad +++ b/rounding.scad @@ -60,7 +60,8 @@ include // or you can specify a list that has length len(path)-2, omitting the two dummy values. // . // If your input path includes collinear points you must use a cut or radius value of zero for those "corners". You can -// choose a nonzero joint parameter, which will cause extra points to be inserted. +// choose a nonzero joint parameter when the collinear points form a 180 degree angle. This will cause extra points to be inserted. +// If the collinear points form a spike (0 degree angle) then round_corners will fail. // . // Examples: // * `method="circle", radius=2`: @@ -75,7 +76,8 @@ include // ignored. Note that $fn is interpreted as the number of points on the roundover curve, which is // not equivalent to its meaning for rounding circles because roundovers are usually small fractions // of a circular arc. When doing continuous curvature rounding be sure to use lots of segments or the effect -// will be hidden by the discretization. +// will be hidden by the discretization. Note that if you use $fn then $fn with "smooth" then $fn points are added at each corner, even +// if the "corner" is flat, with collinear points, so this guarantees a specific output length. // // Figure(2D,Med): // h = 18; @@ -260,10 +262,16 @@ function round_corners(path, method="circle", radius, cut, joint, k, closed=true dk = [ for(i=[0:1:len(path)-1]) let( - angle = vector_angle(select(path,i-1,i+1))/2 + pathbit = select(path,i-1,i+1), + angle = approx(pathbit[0],pathbit[1]) || approx(pathbit[1],pathbit[2]) ? undef + : vector_angle(select(path,i-1,i+1))/2, + f=echo(angle=angle) ) (!closed && (i==0 || i==len(path)-1)) ? [0] : // Force zeros at ends for non-closed parm[i]==0 ? [0] : // If no rounding requested then don't try to compute parameters + assert(is_def(angle), str("Repeated point in path at index ",i," with nonzero rounding")) + assert(!approx(angle,0), closed && i==0 ? "Closing the path causes it to turn back on itself at the end" : + str("Path turns back on itself at index ",i," with nonzero rounding")) (method=="chamfer" && measure=="joint")? [parm[i]] : (method=="chamfer" && measure=="cut") ? [parm[i]/cos(angle)] : (method=="smooth" && measure=="joint") ? [parm[i],k[i]] : @@ -277,10 +285,11 @@ function round_corners(path, method="circle", radius, cut, joint, k, closed=true lengths = [for(i=[0:1:len(path)]) norm(select(path,i)-select(path,i-1))], scalefactors = [ for(i=[0:1:len(path)-1]) - min( + if (closed || (i!=0 && i!=len(path)-1)) + min( lengths[i]/(select(dk,i-1)[0]+dk[i][0]), lengths[i+1]/(dk[i][0]+select(dk,i+1)[0]) - ) + ) ], dummy = verbose ? echo("Roundover scale factors:",scalefactors) : 0 ) @@ -639,12 +648,12 @@ function _path_join(paths,joint,k=0.5,i=0,result=[],relocate=true,closed=false) d_next = is_vector(joint[i]) ? joint[i][1] : joint[i] ) assert(d_first>=0 && d_next>=0, str("Joint value negative when adding path ",i+1)) + assert(d_first