116 lines
2.6 KiB
JavaScript
116 lines
2.6 KiB
JavaScript
var Spline = {};
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Spline.sample_angle = function(type, points, angle) {
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return spline_cmd(0, type, points[0].length, points, angle);
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}
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Spline.bezier_loop = function(cp)
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{
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cp.push(Vector.reflect_point(cp.at(-2),cp.at(-1)));
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cp.push(Vector.reflect_point(cp[1],cp[0]));
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cp.push(cp[0].slice());
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return cp;
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}
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Spline.bezier_node_count = function(cp)
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{
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if (cp.length === 4) return 2;
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return 2 + (cp.length-4)/3;
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}
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Spline.is_bezier = function(t) { return t === Spline.type.bezier; }
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Spline.is_catmull = function(t) { return t === Spline.type.catmull; }
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Spline.bezier2catmull = function(b)
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{
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var c = [];
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for (var i = 0; i < b.length; i += 3)
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c.push(b[i]);
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return c;
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}
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Spline.catmull2bezier = function(c)
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{
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var b = [];
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for (var i = 1; i < c.length-2; i++) {
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b.push(c[i].slice());
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b.push(c[i+1].sub(c[i-1]).scale(0.25).add(c[i]));
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b.push(c[i].sub(c[i+2]).scale(0.25).add(c[i+1]));
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}
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b.push(c[c.length-2]);
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return b;
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}
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Spline.catmull_loop = function(cp)
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{
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cp = cp.slice();
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cp.unshift(cp.last());
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cp.push(cp[1]);
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cp.push(cp[2]);
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return cp;
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}
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Spline.catmull_caps = function(cp)
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{
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if (cp.length < 2) return;
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cp = cp.slice();
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cp.unshift(cp[0].sub(cp[1]).add(cp[0]));
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cp.push(cp.last().sub(cp.at(-2).add(cp.last())));
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return cp;
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}
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Spline.catmull_caps.doc = "Given a set of control points cp, return the necessary caps added to the spline.";
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Spline.catmull2bezier.doc = "Given a set of control points C for a camtull-rom type curve, return a set of cubic bezier points to give the same curve."
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Spline.type = {
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catmull: 0,
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bezier: 1,
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bspline: 2,
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cubichermite: 3
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};
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Spline.bezier_tan_partner = function(points, i)
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{
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if (i%3 === 0) return undefined;
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var partner_i = (i%3) === 2 ? i-1 : i+1;
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return points[i];
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}
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Spline.bezier_cp_mirror = function(points, i)
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{
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if (i%3 === 0) return undefined;
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var partner_i = (i%3) === 2 ? i+2 : i-2;
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var node_i = (i%3) === 2 ? i+1 : i-1;
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if (partner_i >= points.length || node_i >= points.length) return;
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points[partner_i] = points[node_i].sub(points[i]).add(points[node_i]);
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}
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Spline.bezier_point_handles = function(points, i)
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{
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if (!Spline.bezier_is_node(points,i)) return [];
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var a = i-1;
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var b = i+1;
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var c = []
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if (a > 0)
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c.push(a);
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if (b < points.length)
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c.push(b);
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return c;
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}
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Spline.bezier_nodes = function(points)
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{
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var c = [];
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for (var i = 0; i < points.length; i+=3)
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c.push(points[i].slice());
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return c;
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}
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Spline.bezier_is_node = function(points, i) { return i%3 === 0; }
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Spline.bezier_is_handle = function(points, i) { return !Spline.bezier_is_node(points,i); }
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return {Spline};
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