main/src/georegression/geometry/ConvertRotation3D_F64.java
public static void setRotX( double ang, DMatrixRMaj R ) {
		double c = Math.cos( ang );
		double s = Math.sin( ang );

		R.set( 0, 0, 1 );
		R.set( 1, 1, c );
		R.set( 1, 2, -s );
		R.set( 2, 1, s );
		R.set( 2, 2, c );
	}
public static void setRotX( double ang, DMatrixRMaj R ) {
		double c = Math.cos( ang );
		double s = Math.sin( ang );

		R.set( 0, 0, 1 );
		R.set( 1, 1, c );
		R.set( 1, 2, -s );
		R.set( 2, 1, s );
		R.set( 2, 2, c );
	}
Sets the values in the specified matrix to a rotation matrix about the x-axis.

@param ang the angle it rotates a point by in radians.
@param R (Output) Storage for rotation matrix.  Modified.