Use doubles for coordinates and some bugfixes

modules/skybrowser/skybrowsermodule.cpp

@@ -45,6 +45,8 @@
 
 #include <fstream>    
 
+#define _USE_MATH_DEFINES
+#include <math.h>
 
 namespace {
     struct [[codegen::Dictionary(ScreenSpaceSkyBrowser)]] Parameters {
@@ -330,6 +332,27 @@ void SkyBrowserModule::internalInitialize(const ghoul::Dictionary& dict) {
     dataHandler = new WWTDataHandler();
 }
 
+glm::dvec3 SkyBrowserModule::icrsToGalacticCartesian(double ra, double dec, double distance) {
+    // Convert to Galactic Coordinates from ICRS right ascension and declination
+    // https://gea.esac.esa.int/archive/documentation/GDR2/Data_processing/
+    // chap_cu3ast/sec_cu3ast_intro/ssec_cu3ast_intro_tansforms.html#SSS1
+    const glm::dmat3 conversionMatrix = glm::dmat3({
+        -0.0548755604162154,  0.4941094278755837, -0.8676661490190047, // col 0
+        -0.8734370902348850, -0.4448296299600112, -0.1980763734312015, // col 1
+        -0.4838350155487132,  0.7469822444972189,  0.4559837761750669  // col 2
+        });
+    double degToRad = M_PI / 180.0;
+
+    glm::dvec3 rICRS = glm::dvec3(
+        cos(ra * degToRad) * cos(dec * degToRad),
+        sin(ra * degToRad) * cos(dec * degToRad),
+        sin(dec * degToRad)
+    );
+    glm::dvec3 rGalactic = conversionMatrix * rICRS; // on the unit sphere
+
+    return distance * rGalactic;
+}
+
 glm::vec2 SkyBrowserModule::getMousePositionInScreenSpaceCoords(glm::vec2& mousePos) {
     glm::vec2 size = global::windowDelegate->currentWindowSize();
     // Change origin to middle of the window