/**
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* Approximately computes spherical coordinates given a normal.
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* Uses approximate inverse trigonometry for speed and consistency,
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* since inverse trigonometry can differ from vendor-to-vendor and when compared with the CPU.
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*
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* @name czm_approximateSphericalCoordinates
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* @glslFunction
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*
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* @param {vec3} normal arbitrary-length normal.
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*
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* @returns {vec2} Approximate latitude and longitude spherical coordinates.
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*/
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vec2 czm_approximateSphericalCoordinates(vec3 normal) {
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// Project into plane with vertical for latitude
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float latitudeApproximation = czm_fastApproximateAtan(sqrt(normal.x * normal.x + normal.y * normal.y), normal.z);
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float longitudeApproximation = czm_fastApproximateAtan(normal.x, normal.y);
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return vec2(latitudeApproximation, longitudeApproximation);
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}
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