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 PROJ_MAX_RA             360.0
  30 #define PROJ_MIN_RA             0.0
  31
  32 #define PROJ_MAX_DEC            90
  33 #define PROJ_MIN_DEC            -90
  34
  35 #define PROJ_MIN_FOV            0.5
  36 #define PROJ_MAX_FOV            270.0
  37
  38 #define GRID_DEC_TILES  18
  39 #define GRID_RA_TILES   24
  40 #define GRID_DEC_TILE_SIZE      ((PROJ_MAX_DEC - PROJ_MIN_DEC) / GRID_DEC_TILES)
  41 #define GRID_RA_TILE_SIZE       (PROJ_MAX_RA / GRID_RA_TILES)
  42
  43 enum projection_flip {
  44         PF_NONE,
  45         PF_TB,
  46         PF_LR,
  47         PF_LR_TB,
  48 };
  49
  50 enum projection_coords {
  51         PC_RA_DEC,
  52         PC_ALT_AZ,
  53 };
  54
  55 struct projection;
  56
  57 struct transform {
  58         /* Equatorial coords - RA, DEC */
  59         void (*sky_to_proj_equ)(struct projection *projection,
  60                 struct render_coord *c);
  61         void (*proj_to_sky_equ)(struct projection *projection,
  62                 struct render_coord *c);
  63         /* horizontal coords - Alt, Az */
  64         void (*sky_to_proj_hrz)(struct projection *projection,
  65                 struct render_coord *c);
  66         void (*proj_to_sky_hrz)(struct projection *projection,
  67                 struct render_coord *c);
  68 };
  69
  70 struct projection {
  71
  72         /* field of view */
  73         gdouble centre_ra;              /*!< FOV centre RA */
  74         gdouble centre_dec;             /*!< FOV centre DEC */
  75         gdouble centre_az;              /*!< FOV centre RA */
  76         gdouble centre_alt;             /*!< FOV centre DEC */
  77         gdouble centre_ra_rad;          /*!< FOV centre RA */
  78         gdouble centre_dec_rad;         /*!< FOV centre DEC */
  79         gdouble centre_dec_rad_cos;     /*!< FOV centre DEC */
  80         gdouble centre_dec_rad_sin;     /*!< FOV centre DEC */
  81         gdouble fov;                    /*!< vertical FOV size in degrees */
  82
  83         /* sky size */
  84         gint sky_width;                 /*!< Drawing area x size */
  85         gint sky_height;                /*!< Drawing area y size */
  86         gdouble sky_scale;              /*!< Rendering scale */
  87         gdouble sky_mid_width;          /*!< width / 2 */
  88         gdouble sky_mid_height;         /*!< height / 2 */
  89
  90         /* virtual sky clipping box */
  91         gdouble clip_mag_faint;         /*!< Minimum mag */
  92         gdouble clip_mag_bright;        /*!< Maximum mag */
  93
  94         enum projection_flip flip;
  95         enum projection_coords coords;
  96         enum projection_coords grid_coords;
  97
  98         /* sky pixels per degree scale */
  99         gdouble pixels_per_degree;      /*!< pixels per degree */
 100         gdouble pixels_per_radian;      /*!< pixels per radian */
 101
 102         /* transforms */
 103         gdouble sidereal;
 104         struct transform* trans;
 105
 106         /* observer */
 107         gdouble observer_lat_rad;
 108         gdouble observer_lng_rad;
 109         gdouble observer_lat_sin;
 110         gdouble observer_lat_cos;
 111         gdouble hour_angle;
 112
 113         /* grid */
 114         int grid_tile[GRID_RA_TILES][GRID_DEC_TILES];   /*!< Visible grid subtiles */
 115 };
 116
 117 extern struct transform transform_flip_none;
 118 extern struct transform transform_flip_lr;
 119 extern struct transform transform_flip_tb;
 120 extern struct transform transform_flip_lr_tb;
 121
 122 gint projection_set_flip(struct projection *proj, enum projection_flip flip);
 123 void projection_fov_bounds(struct projection *proj,
 124         struct observer_info *observer);
 125 void projection_check_bounds (struct projection* proj);
 126 void projection_set_observer(struct projection *proj,
 127         struct observer_info *observer);
 128 void projection_move_rel_pixels(struct projection *projection,
 129                                         gfloat ra_offset, gfloat dec_offset);
 130
 131 static inline int projection_is_visible0(struct projection* projection,
 132         struct render_object *r)
 133 {
 134         if (r->coord[0].x < 0 || r->coord[0].x > projection->sky_width)
 135                 return 0;
 136         if (r->coord[0].y < 0 || r->coord[0].y > projection->sky_height)
 137                 return 0;
 138         return 1;
 139 }
 140
 141 static inline int projection_is_visible1(struct projection* projection,
 142         struct render_object *r)
 143 {
 144         if (r->coord[1].x < 0 || r->coord[1].x > projection->sky_width)
 145                 return 0;
 146         if (r->coord[1].y < 0 || r->coord[1].y > projection->sky_height)
 147                 return 0;
 148         return 1;
 149 }
 150
 151 #endif