/*  File     :  v2v3.c
 *  
 *  Contents :
 *      XY_to_V2V3 : Convert detector X,Y to pupil V2,V3; used by v2v3()
 *	V2V3_to_XY : Convert field V2,V3 to detector X,Y; used by v2v3()
 *	v2v3 : Compute pupil V2,V3 for a given detector X,Y
 *
 *  Author   :  John Krist 
 *  Date     :  October 2000
 *
 */

#include <stdio.h>
#include <math.h>
#include "tinytim.h"

/*------------------------------------------------------------------------
*  XY_to_V2V3 :
*
*	Convert geometrically distorted detector X,Y pixel position to 
*	V2,V3 field coordinates, with conversion to V2,V3 pupil
*	coordinates.
*
*  Inputs :
*	x, y : Detector pixel position
*  Outputs :
*	v2, v3 : Position in arcsec in pupil coordinate system
*
*  NOTE : This routine only works for the ACS
*-------------------------------------------------------------------------*/
void XY_to_V2V3( float x, float y, float *v2, float *v3 )
{
	/* NOTE : the negative of Pars.v2,v3 are used below since they *
	 * are in pupil coordinates while the transform coefficients *
	 * are in normal field coordinates.			     */

	/* transforms are relative to the reference position */

	x = x - Pars.x_ref;
	y = y - Pars.y_ref;

	*v2 = -Pars.v2 + y*Pars.xy_to_v2[0] + x*Pars.xy_to_v2[1] +
	       y*y*Pars.xy_to_v2[2] + x*y*Pars.xy_to_v2[3] + x*x*Pars.xy_to_v2[4] +
	       y*y*y*Pars.xy_to_v2[5] + x*y*y*Pars.xy_to_v2[6] + 
	       x*x*y*Pars.xy_to_v2[7] + x*x*x*Pars.xy_to_v2[8];

	*v3 = -Pars.v3 + y*Pars.xy_to_v3[0] + x*Pars.xy_to_v3[1] +
	       y*y*Pars.xy_to_v3[2] + x*y*Pars.xy_to_v3[3] + x*x*Pars.xy_to_v3[4] +
	       y*y*y*Pars.xy_to_v3[5] + x*y*y*Pars.xy_to_v3[6] + 
	       x*x*y*Pars.xy_to_v3[7] + x*x*x*Pars.xy_to_v3[8];

	/* convert to V2,V3 pupil coordinate system */

	*v2 = -(*v2);
        *v3 = -(*v3);
}

/*------------------------------------------------------------------------
*  V2V3_to_XY :
*
*	Convert V2,V3 field coordinates to geometrically distorted detector
*	X,Y pixel position 
*
*  Inputs :
*	v2, v3 : Field position in arcsec (NOT in pupil coordinate system)
*  Outputs :
*	x, y : Detector pixel position
*
*  NOTE : This routine only works for the ACS
*-------------------------------------------------------------------------*/
void V2V3_to_XY( float *x, float *y, float v2, float v3 )
{
	v2 = v2 - (-Pars.v2);
	v3 = v3 - (-Pars.v3);

	*x = v3*Pars.v2v3_to_x[0] + v2*Pars.v2v3_to_x[1] +
	     v3*v3*Pars.v2v3_to_x[2] + v2*v3*Pars.v2v3_to_x[3] + 
	     v2*v2*Pars.v2v3_to_x[4] + v3*v3*v3*Pars.v2v3_to_x[5] + 
	     v2*v3*v3*Pars.v2v3_to_x[6] + v2*v2*v3*Pars.v2v3_to_x[7] +
	     v2*v2*v2*Pars.v2v3_to_x[8]; 

	*y = v3*Pars.v2v3_to_y[0] + v2*Pars.v2v3_to_y[1] +
	     v3*v3*Pars.v2v3_to_y[2] + v2*v3*Pars.v2v3_to_y[3] + 
	     v2*v2*Pars.v2v3_to_y[4] + v3*v3*v3*Pars.v2v3_to_y[5] + 
	     v2*v3*v3*Pars.v2v3_to_y[6] + v2*v2*v3*Pars.v2v3_to_y[7] +
	     v2*v2*v2*Pars.v2v3_to_y[8]; 

	/* transforms are relative to reference position */

	*x = *x + Pars.x_ref;
	*y = *y + Pars.y_ref;
}

/*-------------------------------------------------------------------------
*  v2v3 :
*	Compute V2,V3 pupil coordinates for a given detector X,Y position;
*	pupil coordinates are the negative of field coordinates
*
*  Inputs :
*	camera : camera id number
*	  x, y : position on detector 
*  Outputs :
*	v2, v3 : v2,v3 pupil coordinates
*-------------------------------------------------------------------------*/
void v2v3( int camera, int x, int y, float *v2, float *v3 )
{
	float	t;

	if ( camera >= 1 && camera <= 8 )
	{
		/* WFPC1 coordinates are 0-799 */

		/* convert to arcsec from detector center */ 

		x = (x - 412) * Pars.pixel_size;	
		y = (y - 412) * Pars.pixel_size;

		/* adjust for detector rotation with respect to OTA */

		t = (90 + Pars.theta) * M_PI / 180.0;
		*v2 = -(x * cos(t) - y * sin(t)) + Pars.v2;
		*v3 = x * sin(t) + y * cos(t) + Pars.v3;
	}
	else if ( camera >= WFPC2_PC && camera <= WFPC2_WFC_4 )
	{
		/* WFPC2 coordinates are 0-799 */

		/* convert to arcsec from detector center */ 

		x = (x - 420) * Pars.pixel_size;	
		y = (y - 420) * Pars.pixel_size;

		/* adjust for detector rotation with respect to OTA */

		t = (90 + Pars.theta) * M_PI / 180.0;
		*v2 = -(x * cos(t) - y * sin(t)) + Pars.v2;
		*v3 = x * sin(t) + y * cos(t) + Pars.v3;
	}
	else if ( camera >= NICMOS_1 && camera <= NICMOS_3 )
	{
		/* NICMOS coordinates are 0-255 */

		/* convert to arcsec from detector center */ 

		x = (x - 128) * Pars.pixel_size;	
		y = (y - 128) * Pars.pixel_size;

		/* adjust for detector rotation with respect to OTA */

		t = (90 + Pars.theta) * M_PI / 180.0;
		*v2 = -(x * cos(t) - y * sin(t)) + Pars.v2;
		*v3 = x * sin(t) + y * cos(t) + Pars.v3;
	}
	else if ( camera >= ACS_WFC1 && camera <= ACS_SBC )
		XY_to_V2V3( (float)x, (float)y, v2, v3 );
	else
	{
		*v2 = Pars.v2;
		*v3 = Pars.v3;
	}

} /* v2v3 */