X-Git-Url: http://git.scottworley.com/nt3d/blobdiff_plain/2f26ede4efa95cc756a2b3240c2a9e29f0f48486..08b46dbddc6defd45926a69631e3a09ea2273e45:/nt3d.js diff --git a/nt3d.js b/nt3d.js index c69c185..7198e22 100644 --- a/nt3d.js +++ b/nt3d.js @@ -62,6 +62,27 @@ nt3d = { return this.closed_trianglefan([apex].concat(base)).concat( this.trianglefan(base.reverse())); }, + sphere: function(center, radius, latitude_steps, longitude_steps) { + return this.oriented_sphere(center, radius, [0,0,1], [1,0,0], latitude_steps, longitude_steps); + }, + oriented_sphere: function(center, radius, north, greenwich, latitude_steps, longitude_steps) { + var unit_north = this.unit(north); + var north_pole = this.translate_point(this.scale(unit_north, radius), center); + var south_pole = this.translate_point(this.scale(unit_north, -radius), center); + return this.spheroid(north_pole, south_pole, radius, greenwich, latitude_steps, longitude_steps); + }, + spheroid: function(north_pole, south_pole, radius, greenwich, latitude_steps, longitude_steps) { + var delta = this.sub(north_pole, south_pole); + var path = []; + for (var i = 0; i < latitude_steps-1; i++) { + path.push(this.translate_point(south_pole, this.scale(delta, (1-Math.cos(Math.PI*i/(latitude_steps-1)))/2))); + } + path.push(north_pole); + function shape(i) { + return nt3d.circle(radius*Math.sin(Math.PI*i/(latitude_steps-1)), longitude_steps); + } + return this.extrude(path, shape, delta, greenwich); + }, shapenormals_from_closed_path: function(path) { return function(i) { var prev = (i == 0) ? path.length-1 : i-1; @@ -83,6 +104,14 @@ nt3d = { return nt3d.sub(path[i+1], path[i-1]); }; }, + pathnormals_from_point: function(path, p) { + // Use this with any point that is not on any path tangent line + var pathnormals = []; + for (var i = 0; i < path.length; i++) { + pathnormals.push(this.sub(path[i], p)); + } + return pathnormals; + }, to_function: function(thing, make_indexer) { // If thing is a point, just yield thing every time. // If thing is a list of points && make_indexer, index into thing. @@ -211,7 +240,7 @@ nt3d = { }, 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); + return this.scale(a, this.dot(a, b) / (a_magnitude * a_magnitude)); }, project_to_orthogonal: function(a, b) { // The nearest thing to b that is orthogonal to a @@ -220,14 +249,24 @@ nt3d = { 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]]; + translated[i] = this.translate_point(points[i], offset); } return translated; }, + translate_point: function(point, offset) { + return [point[0] + offset[0], + point[1] + offset[1], + point[2] + offset[2]]; + }, angle_between: function(a, b) { // a and b must be unit vectors - return Math.acos(this.dot(a, b)); + var the_dot = this.dot(a, b); + if (the_dot <= -1) { + return Math.PI; + } + if (the_dot >= 1) { + return 0; + } + return Math.acos(the_dot); }, rotate_about_origin: function(points, axis, angle) { // axis must be a unit vector // From http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/ @@ -249,8 +288,8 @@ nt3d = { // 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 + if (Math.abs(angle) < 1e-7) { + // No significant rotation to perform. Bail to avoid // NaNs and numerical error return points; } @@ -265,6 +304,17 @@ nt3d = { angle), center); }, + point_equal: function(a, b, epsilon) { + return Math.abs(a[0] - b[0]) < epsilon && + Math.abs(a[1] - b[1]) < epsilon && + Math.abs(a[2] - b[2]) < epsilon; + }, + degenerate_face_epsilon: 1e-10, + is_degenerate: function(a, b, c) { + return this.point_equal(a, b, this.degenerate_face_epsilon) || + this.point_equal(b, c, this.degenerate_face_epsilon) || + this.point_equal(c, a, this.degenerate_face_epsilon); + }, go: function() { // Remove any previous download links var old_download_link = document.getElementById("nt3d_download"); @@ -286,14 +336,51 @@ nt3d = { // Run user_function this.points = this.user_function.apply(null, params); + + // Do a little validation if (this.points.length % 3 != 0) { alert("Points list length not divisble by 3!"); } - var n = this.points.length / 3; + var nan_count = 0; + var nan_point_count = 0; + var nan_face_count = 0; + for (var i = 0; i < this.points.length/3; i++) { + var nan_in_face = false; + for (var j = 0; j < 3; j++) { + var nan_in_point = false; + for (var k = 0; k < 3; k++) { + if (isNaN(this.points[i*3+j][k])) { + nan_count++; + nan_in_point = true; + nan_in_face = true; + } + } + if (nan_in_point) nan_point_count ++; + } + if (nan_in_face) nan_face_count ++; + } + if (nan_count != 0) { + alert(nan_count + " NaNs in " + nan_point_count + " points in " + nan_face_count + " faces (" + (100 * nan_face_count / (this.points.length/3)) + "% of faces)."); + } + + // Remove degenerate faces + var degenerate_face_count = 0; + for (var i = 0; i < this.points.length/3; i++) { + if (this.is_degenerate(this.points[i*3+0], + this.points[i*3+1], + this.points[i*3+2])) { + this.points.splice(i*3, 3); + i--; + degenerate_face_count ++; + } + } + if (degenerate_face_count != 0) { + console.log("Removed " + degenerate_face_count + " degenerate faces"); + } // Make STL this.stl = "solid " + this.user_function.name + "\n"; - for (var i = 0; i < n; i++) { + for (var i = 0; i < this.points.length/3; i++) { var a = this.points[i*3+0]; var b = this.points[i*3+1]; var c = this.points[i*3+2];