Contribution to add optional double precision floating point support. Define BT_USE_DOUBLE_PRECISION for all involved libraries/apps.

Demos/OpenGL/GlutStuff.h

@@ -19,4 +19,16 @@ class DemoApplication;
 
 int glutmain(int argc, char **argv,int width,int height,const char* title,DemoApplication* demoApp);
 
+#if defined(BT_USE_DOUBLE_PRECISION)
+#define btglLoadMatrix glLoadMatrixd
+#define btglMultMatrix glMultMatrixd
+#define btglColor3 glColor3d
+#define btglVertex3 glVertex3d
+#else
+#define btglLoadMatrix glLoadMatrixf
+#define btglMultMatrix glMultMatrixf
+#define btglColor3 glColor3f
+#define btglVertex3 glVertex3d
+#endif
+
 #endif //GLUT_STUFF_H