Add initial version of lua ra dec conversion function

include/openspace/util/coordinateconversion.h

@@ -26,6 +26,7 @@
 #define __OPENSPACE_CORE___COORDINATECONVERSION___H__
 
 #include <ghoul/glm.h>
+#include <string>
 
 namespace openspace {
 
@@ -39,6 +40,14 @@ namespace openspace {
  */
 glm::dvec3 icrsToGalacticCartesian(float ra, float dec, double distance);
 
+/**
+ * Converts from ICRS (hms and dms) coordinates to decimal degrees.
+ * \param ra Right ascension, given as a string in format "XXhYYmZZs"
+ * \param dec Declination, given as a string in format "+XXdYYmZZs" or "-XXdYYmZZs"
+ * \return The decimal degrees coordinate
+ */
+glm::dvec2 icrsToDecimalDegrees(std::string ra, std::string dec);
+
 } // namespace openspace
 
 #endif // __OPENSPACE_CORE___COORDINATECONVERSION___H__

src/scene/scene.cpp

@@ -731,6 +731,13 @@ scripting::LuaLibrary Scene::luaLibrary() {
                 {},
                 "string",
                 "Returns the world rotation matrix of the scene graph node with the given string as identifier"
+            },
+            {
+                "convertRaDec",
+                &luascriptfunctions::convertRaDec,
+                {},
+                "string, string, float",
+                "Returns the cartesian world position of a ra dec coordinate with distance"
             }
         }
     };

src/scene/scene_lua.inl

@@ -28,6 +28,8 @@
 #include <ghoul/misc/defer.h>
 #include <ghoul/misc/easing.h>
 
+#include <openspace/util/coordinateconversion.h>
+
 namespace openspace {
 
 namespace {
@@ -948,4 +950,21 @@ int worldRotation(lua_State* L) {
     return 1;
 }
 
+int convertRaDec(lua_State* L) {
+    ghoul::lua::checkArgumentsAndThrow(L, 3, "lua::convertRaDec");
+
+    std::string ra = ghoul::lua::value<std::string>(L, 1);
+    std::string dec = ghoul::lua::value<std::string>(L, 2);
+    float distance = ghoul::lua::value<float>(L, 3);
+    lua_settop(L, 0);
+
+    glm::dvec2 degrees = icrsToDecimalDegrees(ra, dec);
+    glm::dvec3 pos = icrsToGalacticCartesian(degrees.x, degrees.y, distance);
+
+    ghoul::lua::push(L, pos);
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
+    return 1;
+}
+
 }  // namespace openspace::luascriptfunctions

src/util/coordinateconversion.cpp

@@ -58,4 +58,47 @@ glm::dvec3 icrsToGalacticCartesian(float ra, float dec, double distance) {
     return distance * rGalactic;
 }
 
+// ra format "XXhYYmZZs" or "XhYmZs"
+// dec format "+XXdYYmZZs", "-XXdYYmZZs" or "-XdYmZs"
+glm::dvec2 icrsToDecimalDegrees(std::string ra, std::string dec) {
+    if (ra.size() > 9 || ra.size() < 6 || dec.size() > 10 || dec.size() < 7) {
+        // Stirngs too big or small
+    }
+
+    // Parse right ascension
+    size_t ra_h_index = ra.find('h');
+    size_t ra_m_index = ra.find('m');
+    size_t ra_s_index = ra.find('s');
+    if (ra_h_index == std::string::npos || ra_m_index == std::string::npos ||
+        ra_s_index == std::string::npos)
+    {
+        // Format not correct
+    }
+
+    float ra_hours = std::stof(ra.substr(0, ra_h_index));
+    float ra_minutes = std::stof(ra.substr(ra_h_index + 1, ra_m_index - ra_h_index - 1));
+    float ra_seconds = std::stof(ra.substr(ra_m_index + 1, ra_s_index - ra_m_index - 1));
+
+    // Parse declination
+    size_t dec_d_index = dec.find('d');
+    size_t dec_m_index = dec.find('m');
+    size_t dec_s_index = dec.find('s');
+    if (dec_d_index == std::string::npos || dec_m_index == std::string::npos ||
+        dec_s_index == std::string::npos)
+    {
+        // Format not correct
+    }
+
+    float dec_degrees = std::stof(dec.substr(0, dec_d_index));
+    float dec_minutes = std::stof(dec.substr(dec_d_index + 1, dec_m_index - dec_d_index - 1));
+    float dec_seconds = std::stof(dec.substr(dec_m_index + 1, dec_s_index - dec_m_index - 1));
+
+    // Convert from hours, minutes, sewconds to degrees
+    float sign = signbit(dec_degrees) ? -1.f : 1.f;
+    float ra_deg = (ra_hours * 15.0) + (ra_minutes * 15 / 60.0) + (ra_seconds * 15 / 3600.0);
+    float dec_deg = (abs(dec_degrees) + (dec_minutes / 60.0) + (dec_seconds / 3600.0)) * sign;
+
+    return glm::dvec2(ra_deg, dec_deg);
+}
+
 } // namespace openspace