/* xform.h */

/*
 * Mesa 3-D graphics library
 * Version:  1.2
 * Copyright (C) 1995  Brian Paul  (brianp@ssec.wisc.edu)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
$Id: xform.h,v 1.8 1995/06/02 18:52:50 brianp Exp $

$Log: xform.h,v $
 * Revision 1.8  1995/06/02  18:52:50  brianp
 * replaced 0.00001 with 0.00001F (avoid a double/float conversion)
 *
 * Revision 1.7  1995/05/22  20:59:34  brianp
 * Release 1.2
 *
 * Revision 1.6  1995/03/24  17:01:15  brianp
 * removed assert() call
 *
 * Revision 1.5  1995/03/10  15:20:06  brianp
 * added divide by zero check to TRANSFORM_NORMAL
 *
 * Revision 1.4  1995/03/09  21:42:45  brianp
 * new ModelViewInv matrix logic
 *
 * Revision 1.3  1995/03/09  20:08:39  brianp
 * introduced TRANSFORM_POINT and TRANSFORM_NORMAL macros
 *
 * Revision 1.2  1995/03/04  19:25:29  brianp
 * 1.1 beta revision
 *
 * Revision 1.1  1995/02/24  14:28:31  brianp
 * Initial revision
 *
 */


#ifndef XFORM_H
#define XFORM_H


#include "context.h"


/* Map NDC coords to window coords: */
#define MAP_X( X )	( (X) * CC.Viewport.Sx + CC.Viewport.Tx )
#define MAP_Y( Y )	( (Y) * CC.Viewport.Sy + CC.Viewport.Ty )
#define MAP_Z( Z )	( (Z) * CC.Viewport.Sz + CC.Viewport.Tz )



/*
 * Transform a point (column vector) by a matrix:   Q = M * P
 */
#ifdef DEBUG
#define TRANSFORM_POINT( Q, M, P )   gl_transform_point( Q, M, P );
#else
#define TRANSFORM_POINT( Q, M, P )					\
   Q[0] = M[0] * P[0] + M[4] * P[1] + M[8] *  P[2] + M[12] * P[3];	\
   Q[1] = M[1] * P[0] + M[5] * P[1] + M[9] *  P[2] + M[13] * P[3];	\
   Q[2] = M[2] * P[0] + M[6] * P[1] + M[10] * P[2] + M[14] * P[3];	\
   Q[3] = M[3] * P[0] + M[7] * P[1] + M[11] * P[2] + M[15] * P[3];
#endif



/*
 * Transform a normal vector by the inverse modelview matrix:  M = N * ModelInv
 */
#ifdef DEBUG
#define TRANSFORM_NORMAL( M, N )   gl_transform_normal( M, N );
#else
#define TRANSFORM_NORMAL( M, N )					\
   M[0] = N[0] * CC.ModelViewInv[0] + N[1] * CC.ModelViewInv[1]		\
        + N[2] * CC.ModelViewInv[2];					\
   M[1] = N[0] * CC.ModelViewInv[4] + N[1] * CC.ModelViewInv[5]		\
        + N[2] * CC.ModelViewInv[6];					\
   M[2] = N[0] * CC.ModelViewInv[8] + N[1] * CC.ModelViewInv[9]		\
        + N[2] * CC.ModelViewInv[10];					\
   if (CC.Transform.Normalize) {					\
      /* scale to unit length */					\
      GLfloat len = sqrt( M[0]*M[0] + M[1]*M[1] + M[2]*M[2] );		\
      if (len>0.00001F) {						\
	 M[0] /= len;  M[1] /= len;  M[2] /= len;			\
      }									\
   }
#endif



extern void gl_transform_point( GLfloat q[4],
			        const GLfloat m[16], const GLfloat p[4] );


extern void gl_transform_normal( GLfloat m[3], const GLfloat n[3] );


extern void gl_transform_vector( GLfloat u[4],
				 const GLfloat v[4], const GLfloat m[16] );


extern void gl_compute_modelview_inverse( void );


extern void gl_load_matrix( const GLfloat *m );

extern void gl_mult_matrix( const GLfloat *m );

extern void gl_viewport( GLint x, GLint y, GLsizei width, GLsizei height );

extern void gl_compute_viewport( struct gl_context *c,
				 GLint x, GLint y,
				 GLsizei width, GLsizei height );


#endif