fix GLES compatibility

Author: 10110111

src/core/RefractionExtinction.cpp

@@ -292,9 +292,9 @@ float REFRACTION_sin(float x)
 // Workaround for Intel's and AMD's unusable implementation of asin, which leads to time-dependent shifts of the Moon from its refracted positions.
 float REFRACTION_asin(float x)
 {
-	float sign = x < 0 ? -1 : 1;
-	if(x < 0) x = -x;
-	x = 2 * sqrt(1 - x) - 1;
+	float sign = x < 0. ? -1. : 1.;
+	if(x < 0.) x = -x;
+	x = 2. * sqrt(1. - x) - 1.;
 	float v = 0.848061881596496 + x*(-0.755929497461161 + x*(-0.0539853235799928 + x*(-0.025701166121295 + x*(-0.00723634508887381 +
 	           x*(-0.00314276748524976 + x*(-0.00101365621070969 + x*(-0.000411380592372285 + x*(-0.000428167561924693 - 0.000213293541786718*x))))))));
 	return v * sign;