68 lines
1.4 KiB
JavaScript
68 lines
1.4 KiB
JavaScript
var shape = {};
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shape.sphere = {};
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shape.circle = {};
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shape.sphere.volume = function(r) { return Math.pi*r*r*r*4/3; };
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shape.sphere.random = function(r,theta,phi)
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{
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if (typeof r === 'number') r = [r,r];
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theta ??= [0,1];
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phi ??= [-0.5,0.5];
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if (typeof theta === 'number') theta = [theta,theta];
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if (typeof phi === 'number') phi = [phi,phi];
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var ra = Math.random_range(r[0],r[1]);
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var ta = Math.turn2rad(Math.random_range(theta[0],theta[1]));
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var pa = Math.turn2rad(Math.random_range(phi[0],phi[1]));
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return [
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ra*Math.sin(ta)*Math.cos(pa),
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ra*Math.sin(ta)*Math.sin(pa),
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ra*Math.cos(ta)
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];
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}
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shape.circle.area = function(r) { return Math.pi*r*r; };
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shape.circle.random = function(r,theta)
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{
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return shape.sphere.random(r,theta).xz;
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}
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shape.box = function(w,h) {
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w /= 2;
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h /= 2;
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var points = [
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[w,h],
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[-w,h],
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[-w,-h],
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[w,-h]
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];
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return points;
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};
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shape.ngon = function(radius, n) {
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return shape.arc(radius,360,n);
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};
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shape.arc = function(radius, angle, n, start) {
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start ??= 0;
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start = Math.deg2rad(start);
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if (angle >= 360)
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angle = 360;
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if (n <= 1) return [];
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var points = [];
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angle = Math.deg2rad(angle);
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var arclen = angle/n;
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for (var i = 0; i < n; i++)
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points.push(Vector.rotate([radius,0], start + (arclen*i)));
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return points;
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};
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shape.circle.points = function(radius, n) {
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if (n <= 1) return [];
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return shape.arc(radius, 360, n);
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};
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