diff options
author | Benjamin Barenblat <bbarenblat@gmail.com> | 2022-01-17 23:12:32 -0500 |
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committer | Benjamin Barenblat <bbarenblat@gmail.com> | 2022-01-30 15:55:27 -0500 |
commit | d0e18bdb7924c71cdca8dd983711171d87ef28be (patch) | |
tree | 6be11aae0b7c8874e6507b75b4ef26d1353952c7 /src/astro.h |
glplanet draws Earth like it currently appears from space, putting
nighttime areas in shadow and daytime areas in light. It’s modeled
after Xplanet (http://xplanet.sourceforge.net/), but whereas Xplanet is
entirely a CPU-resident program, glplanet draws using OpenGL. It’s thus
much less resource-intensive, particularly when using high-resolution
textures.
Diffstat (limited to 'src/astro.h')
-rw-r--r-- | src/astro.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/src/astro.h b/src/astro.h new file mode 100644 index 0000000..26dcc04 --- /dev/null +++ b/src/astro.h @@ -0,0 +1,44 @@ +// Copyright 2022 Benjamin Barenblat +// +// Licensed under the Apache License, Version 2.0 (the "License"); you may not +// use this file except in compliance with the License. You may obtain a copy of +// the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +// License for the specific language governing permissions and limitations under +// the License. + +#ifndef GLPLANET_SRC_ASTRO_H_ +#define GLPLANET_SRC_ASTRO_H_ + +#include <chrono> +#include <utility> + +#include "third_party/date/include/date/tz.h" + +namespace glplanet { + +// The apparent right ascension and declination of the sun, in radians. Accurate +// to 0.01 degrees. +std::pair<double, double> SunEquatorialPosition( + std::chrono::time_point<date::tai_clock, + std::chrono::milliseconds>) noexcept; + +// The apparent sidereal time at Greenwich, in radians. +double ApparentSiderealTimeAtGreenwich( + std::chrono::time_point<date::tai_clock, + std::chrono::milliseconds>) noexcept; + +// The east longitude and north latitude of the location observing a Sun transit +// (i.e., the location at which it's high noon), in radians. +std::pair<double, double> HighNoonLocation( + std::chrono::time_point<date::tai_clock, + std::chrono::milliseconds>) noexcept; + +} // namespace glplanet + +#endif // GLPLANET_SRC_ASTRO_H_ |