Fixed NifSkope unable to save a mesh if it has bhkCompressedMeshShape…

…Data blocks

Fixes hexabits#67 , niftools#242

Bonus: refactored the NifStream code so this kind of bugs would happen less likely in the future (added asserts in strategic places, moved boilerplate code to macros or functions, and so on). This refactor also fixes a few other potential bugs on reading and writing meshes.

lib/half.h

@@ -15,4 +15,23 @@ half_sub( uint16_t ha, uint16_t hb )
   return half_add( ha, hb ^ 0x8000 );
 }
 
+
+// Added for NifSkope - BEGIN
+
+inline float halfToFloat( uint16_t u )
+{
+	union { float f; uint32_t i; } hv;
+	hv.i = half_to_float( u );
+	return hv.f;
+}
+
+inline uint16_t floatToHalf( float f )
+{
+	union { float f; uint32_t i; } hv;
+	hv.f = f;
+	return half_from_float( hv.i );
+}
+
+// Added for NifSkope - END
+
 #endif /* HALF_H */

src/io/MeshFile.cpp

@@ -132,17 +132,12 @@ quint32 MeshFile::readMesh()
 
 		for ( int i = 0; i < coords[0].count(); i++ ) {
 			uint16_t u, v;
-			union { float f; uint32_t i; } uu, vu;
-
 			in >> u;
 			in >> v;
 
-			uu.i = half_to_float(u);
-			vu.i = half_to_float(v);
-
 			Vector2 coord;
-			coord[0] = uu.f;
-			coord[1] = vu.f;
+			coord[0] = halfToFloat( u );
+			coord[1] = halfToFloat( v );
 
 			coords[0][i] = coord;
 		}
@@ -154,16 +149,12 @@ quint32 MeshFile::readMesh()
 
 		for ( int i = 0; i < coords[1].count(); i++ ) {
 			uint16_t u, v;
-			union { float f; uint32_t i; } uu, vu;
-
 			in >> u;
 			in >> v;
-			uu.i = half_to_float(u);
-			vu.i = half_to_float(v);
 
 			Vector2 coord;
-			coord[0] = uu.f;
-			coord[1] = vu.f;
+			coord[0] = halfToFloat( u );
+			coord[1] = halfToFloat( v );
 			coords[1][i] = coord;
 		}