X-Git-Url: http://git.scottworley.com/nt3d/blobdiff_plain/a26d096067f110dc88756789d771851ae58e0d1e..0ee732b2898771d951a5dc4b79c1aaa3ce47b48b:/nt3d.js diff --git a/nt3d.js b/nt3d.js index 9d45486..a4d3977 100644 --- a/nt3d.js +++ b/nt3d.js @@ -23,11 +23,143 @@ nt3d = { return this.triangle(a, b, c).concat( this.triangle(c, d, a)); }, + trianglefan: function(fan) { + var result = []; + for (var i = 2; i < fan.length; i++) { + result.push(fan[0], fan[i-1], fan[i]); + } + return result; + }, + closed_trianglefan: function(fan) { + return this.trianglefan(fan.concat([fan[1]])); + }, + quadstrip: function(strip) { + if (strip.length % 2 != 0) { + alert("quadstrip length not divisble by 2!"); + } + var result = []; + for (var i = 2; i < strip.length; i += 2) { + result = result.concat(this.quad(strip[i-2], strip[i-1], strip[i+1], strip[i])); + } + return result; + }, + closed_quadstrip: function(strip) { + return this.quadstrip(strip.concat([strip[0], strip[1]])); + }, + circle: function(r, n) { + var points = []; + for (var i = 0; i < n; i++) { + points.push([r*Math.cos(2*Math.PI*i/n), + r*Math.sin(2*Math.PI*i/n), + 0]); + } + return points; + }, + cone: function(base_center, apex, radius, steps) { + var base = this.circle(radius, steps); + base = this.rotate_onto(base, [0,0,1], this.sub(apex, base_center)); + base = this.translate(base, base_center); + return this.closed_trianglefan([apex].concat(base)).concat( + this.trianglefan(base.reverse())); + }, + extrude: function(path, shape, shapenormals, pathnormals) { + + var guts_result = nt3d._extrude_guts(path, shape, shapenormals, pathnormals); + // Add the end-caps + // XXX: This doesn't work if shape is not convex + return guts_result.points.concat( + nt3d.trianglefan(guts_result.first_loop.reverse()), + nt3d.trianglefan(guts_result.last_loop)); + + }, + closed_extrude: function(path, shape, shapenormals, pathnormals) { + var guts_result = nt3d._extrude_guts(path, shape, shapenormals, pathnormals); + // Stitch the ends together + return guts_result.points.concat( + nt3d.closed_quadstrip(nt3d.zip(guts_result.first_loop, guts_result.last_loop))); + }, + _fix_pathnormals: function(shapenormals, pathnormals) { + // Fix pathnormals[i] to be perfectly perpendicular to + // shapenormals[i]. This lets extrude callers be sloppy + // with pathnormals, which can greatly simplify things. + var fixedpathnormals = []; + for (var i = 0; i < pathnormals.length; i++) { + var proj = this.project(shapenormals[i], pathnormals[i]); + fixedpathnormals[i] = this.sub(pathnormals[i], proj); + } + return fixedpathnormals; + }, + _extrude_guts: function(path, shape, shapenormals, pathnormals) { + var fixedpathnormals = this._fix_pathnormals(shapenormals, pathnormals); + var result = { points: [] }; + var prev_loop; + for (var i = 0; i < path.length; i++) { + // loop is shape in 3d with (0,0) at path[i], shape's + // z axis in the direction of shapenormals[i], and + // shape's x axis in the direction of pathnormals[i]. + // We tack [1,0,0] onto the end as a hack to see where + // it ends up after rotation. This is removed later. + var loop = shape.concat([[1,0,0]]); + + // This is done in three steps: + // 1. Rotate shape out of the xy plane so that [0,0,1] + // becomes shapenormals[i]. This puts the shape in + // the correct plane, but does not constrain its + // rotation about shapenormals[i]. + loop = this.rotate_onto(loop, [0,0,1], shapenormals[i]); + var shapex = loop.pop(); + + // 2. Rotate around shapenormals[i] so that [1,0,0] + // becomes fixedpathnormals[i]. + loop = this.rotate_onto(loop, shapex, fixedpathnormals[i]); + + // (This would probably be faster and more numerically stable + // if the two rotations were applied as one combined operation + // rather than separate steps.) + + // 3. Translate to path[i]. + loop = this.translate(loop, path[i]); + + if (i == 0) { + result.first_loop = loop; + } else { + result.points = result.points.concat(nt3d.closed_quadstrip(nt3d.zip(loop, prev_loop))); + } + prev_loop = loop; + } + result.last_loop = prev_loop; + return result; + }, + zip: function(a, b) { + var result = []; + if (a.length != b.length) { + alert("Zip over different-sized inputs"); + } + for (var i = 0; i < a.length; i++) { + result.push(a[i], b[i]); + } + return result; + }, + magnitude: function(a) { + return Math.sqrt(a[0]*a[0] + a[1]*a[1] + a[2]*a[2]); + }, + unit: function(a) { + return this.scale(a, 1 / this.magnitude(a)); + }, sub: function(a, b) { return [a[0] - b[0], a[1] - b[1], a[2] - b[2]]; }, + neg: function(a) { + return [-a[0], -a[1], -a[2]]; + }, + dot: function(a, b) { + return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; + }, + scale: function(v, s) { // Scale vector v by scalar s + return [s*v[0], s*v[1], s*v[2]]; + }, cross: function(a, b) { return [a[1]*b[2] - a[2]*b[1], a[2]*b[0] - a[0]*b[2], @@ -36,11 +168,75 @@ nt3d = { normal: function(a, b, c) { return this.cross(this.sub(a, b), this.sub(b, c)); }, + project: function(a, b) { // Project b onto a + var a_magnitude = this.magnitude(a); + return this.scale(a, this.dot(a, b) / a_magnitude * a_magnitude); + }, + translate: function(points, offset) { + var translated = []; + for (var i = 0; i < points.length; i++) { + translated[i] = [points[i][0] + offset[0], + points[i][1] + offset[1], + points[i][2] + offset[2]]; + } + return translated; + }, + angle_between: function(a, b) { // a and b must be unit vectors + return Math.acos(this.dot(a, b)); + }, + rotate_about_origin: function(points, axis, angle) { // axis must be a unit vector + // From http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/ + var cosangle = Math.cos(angle); + var sinangle = Math.sin(angle); + var rotated = []; + for (var i = 0; i < points.length; i++) { + var p = points[i]; + var tmp = this.dot(p, axis) * (1 - cosangle); + rotated[i] = [ + axis[0]*tmp + p[0]*cosangle + (-axis[2]*p[1] + axis[1]*p[2])*sinangle, + axis[1]*tmp + p[1]*cosangle + ( axis[2]*p[0] - axis[0]*p[2])*sinangle, + axis[2]*tmp + p[2]*cosangle + (-axis[1]*p[0] + axis[0]*p[1])*sinangle]; + } + return rotated; + }, + rotate_onto: function(points, a, b) { + // Rotate points such that a (in points-space) maps onto b + // by crossing a and b to get a rotation axis and using + // angle_between to get a rotation angle. + var angle = this.angle_between(this.unit(a), this.unit(b)); + if (Math.abs(angle) < 1e-15) { + // No siginificant rotation to perform. Bail to avoid + // NaNs and numerical error + return points; + } + var axis = this.unit(this.cross(a, b)); + return this.rotate_about_origin(points, axis, angle); + }, + rotate: function(points, center, axis, angle) { // axis must be a unit vector + return this.translate( + this.rotate_about_origin( + this.translate(points, this.neg(center)), + axis, + angle), + center); + }, go: function() { + // Remove any previous download links + var old_download_link = document.getElementById("nt3d_download"); + if (old_download_link) { + old_download_link.parentNode.removeChild(old_download_link); + } + + // Continue in a callback, so that there's not a stale download + // link hanging around while we process. + setTimeout(function(the_this) { (function() { + // Get params from form var params = []; for (var i = 0; i < this.user_params.length; i++) { - params[i] = this.form.elements["param"+i].value; + var as_string = this.form.elements["param"+i].value; + var as_num = +as_string; + params[i] = isNaN(as_num) ? as_string : as_num; } // Run user_function @@ -67,11 +263,6 @@ nt3d = { } this.stl += "endsolid " + this.user_function.name + "\n"; - // Remove any previous download links - var old_download_link = document.getElementById("nt3d_download"); - if (old_download_link) { - old_download_link.parentNode.removeChild(old_download_link); - } // Offer result as download var download_link = document.createElement("a"); @@ -82,6 +273,8 @@ nt3d = { download_link.setAttribute("href", "data:application/sla," + encodeURIComponent(this.stl)); this.ui.appendChild(download_link); setTimeout(function() { download_link.setAttribute("style", "-webkit-transition: background-color 0.4s; -moz-transition: background-color 0.4s; -o-transition: background-color 0.4s; -ms-transition: background-color 0.4s; transition: background-color 0.4s; background-color: inherit"); }, 0); + + }).call(the_this); }, 0, this); // (We were in a callback this whole time, remember?) }, framework: function (f, params) { this.user_function = f;