79 lines
2.5 KiB
JavaScript
79 lines
2.5 KiB
JavaScript
import compose from "./compose.js";
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import {abs, asin, atan2, cos, degrees, pi, radians, sin, tau} from "./math.js";
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function rotationIdentity(lambda, phi) {
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if (abs(lambda) > pi) lambda -= Math.round(lambda / tau) * tau;
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return [lambda, phi];
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}
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rotationIdentity.invert = rotationIdentity;
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export function rotateRadians(deltaLambda, deltaPhi, deltaGamma) {
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return (deltaLambda %= tau) ? (deltaPhi || deltaGamma ? compose(rotationLambda(deltaLambda), rotationPhiGamma(deltaPhi, deltaGamma))
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: rotationLambda(deltaLambda))
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: (deltaPhi || deltaGamma ? rotationPhiGamma(deltaPhi, deltaGamma)
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: rotationIdentity);
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}
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function forwardRotationLambda(deltaLambda) {
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return function(lambda, phi) {
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lambda += deltaLambda;
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if (abs(lambda) > pi) lambda -= Math.round(lambda / tau) * tau;
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return [lambda, phi];
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};
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}
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function rotationLambda(deltaLambda) {
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var rotation = forwardRotationLambda(deltaLambda);
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rotation.invert = forwardRotationLambda(-deltaLambda);
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return rotation;
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}
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function rotationPhiGamma(deltaPhi, deltaGamma) {
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var cosDeltaPhi = cos(deltaPhi),
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sinDeltaPhi = sin(deltaPhi),
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cosDeltaGamma = cos(deltaGamma),
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sinDeltaGamma = sin(deltaGamma);
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function rotation(lambda, phi) {
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var cosPhi = cos(phi),
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x = cos(lambda) * cosPhi,
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y = sin(lambda) * cosPhi,
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z = sin(phi),
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k = z * cosDeltaPhi + x * sinDeltaPhi;
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return [
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atan2(y * cosDeltaGamma - k * sinDeltaGamma, x * cosDeltaPhi - z * sinDeltaPhi),
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asin(k * cosDeltaGamma + y * sinDeltaGamma)
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];
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}
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rotation.invert = function(lambda, phi) {
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var cosPhi = cos(phi),
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x = cos(lambda) * cosPhi,
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y = sin(lambda) * cosPhi,
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z = sin(phi),
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k = z * cosDeltaGamma - y * sinDeltaGamma;
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return [
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atan2(y * cosDeltaGamma + z * sinDeltaGamma, x * cosDeltaPhi + k * sinDeltaPhi),
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asin(k * cosDeltaPhi - x * sinDeltaPhi)
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];
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};
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return rotation;
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}
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export default function(rotate) {
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rotate = rotateRadians(rotate[0] * radians, rotate[1] * radians, rotate.length > 2 ? rotate[2] * radians : 0);
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function forward(coordinates) {
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coordinates = rotate(coordinates[0] * radians, coordinates[1] * radians);
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return coordinates[0] *= degrees, coordinates[1] *= degrees, coordinates;
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}
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forward.invert = function(coordinates) {
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coordinates = rotate.invert(coordinates[0] * radians, coordinates[1] * radians);
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return coordinates[0] *= degrees, coordinates[1] *= degrees, coordinates;
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};
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return forward;
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}
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