src/sky/projection.h

   1 /*
   2  * Copyright (C) 2008 Liam Girdwood
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifndef __PROJECTION_H
  21 #define __PROJECTION_H
  22
  23 #include <libnova/ln_types.h>
  24 #include <glib-2.0/glib.h>
  25
  26 #include "render.h"
  27 #include "settings.h"
  28
  29 #define GRID_DEC_TILES  19
  30 #define GRID_RA_TILES   24
  31
  32 enum projection_flip {
  33         PF_NONE,
  34         PF_TB,
  35         PF_LR,
  36         PF_LR_TB,
  37 };
  38
  39 enum projection_coords {
  40         PC_RA_DEC,
  41         PC_ALT_AZ,
  42 };
  43
  44 struct projection;
  45
  46 struct transform {
  47         /* Equatorial coords - RA, DEC */
  48         void (*sky_to_proj_equ)(struct projection *projection,
  49                 struct render_coord *c);
  50         void (*proj_to_sky_equ)(struct projection *projection,
  51                 struct render_coord *c);
  52         /* horizontal coords - Alt, Az */
  53         void (*sky_to_proj_hrz)(struct projection *projection,
  54                 struct render_coord *c);
  55         void (*proj_to_sky_hrz)(struct projection *projection,
  56                 struct render_coord *c);
  57 };
  58
  59 struct projection {
  60
  61         /* field of view */
  62         gdouble centre_ra;              /*!< FOV centre RA */
  63         gdouble centre_dec;             /*!< FOV centre DEC */
  64         gdouble centre_1ra;             /*!< FOV centre RA */
  65         gdouble centre_1dec;            /*!< FOV centre DEC */
  66         gdouble centre_ra_rad;          /*!< FOV centre RA */
  67         gdouble centre_dec_rad;         /*!< FOV centre DEC */
  68         gdouble centre_dec_rad_cos;     /*!< FOV centre DEC */
  69         gdouble centre_dec_rad_sin;     /*!< FOV centre DEC */
  70         gdouble fov;                    /*!< vertical FOV size in degrees */
  71
  72         /* sky size */
  73         gint sky_width;                 /*!< Drawing area x size */
  74         gint sky_height;                /*!< Drawing area y size */
  75         gdouble sky_scale;              /*!< Rendering scale */
  76         gdouble sky_mid_width;          /*!< width / 2 */
  77         gdouble sky_mid_height;         /*!< height / 2 */
  78
  79         /* virtual sky clipping box */
  80         gdouble clip_mag_faint;         /*!< Minimum mag */
  81         gdouble clip_mag_bright;        /*!< Maximum mag */
  82
  83         enum projection_flip flip;
  84         enum projection_coords coords;
  85         enum projection_coords grid_coords;
  86
  87         /* sky pixels per degree scale */
  88         gdouble pixels_per_degree;      /*!< pixels per degree */
  89         gdouble pixels_per_radian;      /*!< pixels per radian */
  90
  91         /* transforms */
  92         gdouble sidereal;
  93         struct transform* trans;
  94
  95         /* observer */
  96         gdouble observer_lat_rad;
  97         gdouble observer_lng_rad;
  98         gdouble observer_lat_sin;
  99         gdouble observer_lat_cos;
 100         gdouble hour_angle;
 101
 102         /* grid */
 103         int grid_tile[GRID_RA_TILES][GRID_DEC_TILES];   /*!< Visible grid subtiles */
 104 };
 105
 106 extern struct transform transform_flip_none;
 107 extern struct transform transform_flip_lr;
 108 extern struct transform transform_flip_tb;
 109 extern struct transform transform_flip_lr_tb;
 110
 111 gint projection_set_flip(struct projection *proj, enum projection_flip flip);
 112 void projection_fov_bounds(struct projection *proj,
 113         struct observer_info *observer);
 114 void projection_check_bounds (struct projection* proj);
 115 void projection_set_observer(struct projection *proj,
 116         struct observer_info *observer);
 117 void projection_move_rel_pixels(struct projection *projection,
 118                                         gfloat ra_offset, gfloat dec_offset);
 119
 120 static inline int projection_is_visible0(struct projection* projection,
 121         struct render_object *r)
 122 {
 123         if (r->coord[0].x < 0 || r->coord[0].x > projection->sky_width)
 124                 return 0;
 125         if (r->coord[0].y < 0 || r->coord[0].y > projection->sky_height)
 126                 return 0;
 127         return 1;
 128 }
 129
 130 static inline int projection_is_visible1(struct projection* projection,
 131         struct render_object *r)
 132 {
 133         if (r->coord[1].x < 0 || r->coord[1].x > projection->sky_width)
 134                 return 0;
 135         if (r->coord[1].y < 0 || r->coord[1].y > projection->sky_height)
 136                 return 0;
 137         return 1;
 138 }
 139
 140 #endif