#include <cmath>
-#include <plib/sg.h>
+// Make sure PI is defined in its various forms
+#ifndef SGD_PI // remove me once FlightGear no longer uses PLIB
-// Make sure PI is defined in its various forms
+#ifdef M_PI
+const double SGD_PI = M_PI;
+const float SG_PI = M_PI;
+#else
+const float SG_PI = 3.1415926535f;
+const double SGD_PI = 3.1415926535;
+#endif
-// SG_PI and SGD_PI (float and double) come from plib/sg.h
+#endif // of PLIB-SG guard
/** 2 * PI */
-#define SGD_2PI 6.28318530717958647692
+const double SGD_2PI = SGD_PI * 2.0;
/** PI / 2 */
#ifdef M_PI_2
#endif
/** PI / 4 */
-#define SGD_PI_4 0.78539816339744830961
+const double SGD_PI_4 = 0.78539816339744830961;
+
+#ifndef SGD_DEGREES_TO_RADIANS // // remove me once FlightGear no longer uses PLIB
+
+const double SGD_DEGREES_TO_RADIANS = SGD_PI / 180.0;
+const double SGD_RADIANS_TO_DEGREES = 180.0 / SGD_PI;
+
+const float SG_DEGREES_TO_RADIANS = SG_PI / 180.0f;
+const float SG_RADIANS_TO_DEGREES = 180.0f / SG_PI;
+
+#endif // of PLIB-SG guard
/** \def SG_E "e" */
#ifdef M_E