(svn r4281) -Cleanup: Begun cleaning up elrail code a bit, mostly comments and enum/array alignment

This commit is contained in:
celestar 2006-04-05 08:28:03 +00:00
parent 8362990f8c
commit 4acb8d5364
2 changed files with 223 additions and 134 deletions

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@ -1,6 +1,6 @@
/* $Id$ */
/** @file elrail.c
* This file deals with displaying wires and pylons for electric railway systems.
This file deals with displaying wires and pylons for electric railways.
<h2>Basics</h2>
<h3>Tile Types</h3>
@ -22,21 +22,23 @@ Group 3: Tiles with both an odd X and Y coordnate.
<h4>Control Points</h4>
A Pylon Control Point (PCP) is a position where a wire (or rather two)
is mounted onto a pylon.
Each NRT does contain 4 PCPs which are mapped to a byte
variable and are represented by the DiagDirection enum:
Each NRT does contain 4 PCPs which are bitmapped to a byte
variable and are represented by the DiagDirection enum
A wire that ends on the PCP has a dark ending, otherwise the end is bright.<p>
Each track ends on two PCPs and thus requires one pylon on each end. However,
there is one exception: Straight-and-level tracks only have one pylon every
other tile.
Now on each edge there are two PCPs: One from each adjacent tile. Both PCPs are merged
using an OR matrix (i. e. if one tile needs a PCP at the postion in question, both
tiles get it).
Now on each edge there are two PCPs: One from each adjacent tile. Both PCPs
are merged using an OR operation (i. e. if one tile needs a PCP at the postion
in question, both tiles get it).
<h4>Position Points</h4>
A Pylon Position Point (PPP) is a position where a pylon is located on the ground.
Each PCP owns 8 in (45 degree steps) PPPs that are located around it. PPPs are numbered
0 to 7 with 0 starting north and numbering in clockwise direction. Each track bit has PPPs
that are impossible (because the pylon would be situated on the track), preferred (because
the pylon would be rectangular to the track). PPPs are represented by the Direction enum.
A Pylon Position Point (PPP) is a position where a pylon is located on the
ground. Each PCP owns 8 in (45 degree steps) PPPs that are located around
it. PPPs are represented using the Direction enum. Each track bit has PPPs
that are impossible (because the pylon would be situated on the track) and
some that are preferred (because the pylon would be rectangular to the track).
<img src="../../elrail_tile.png">
<img src="../../elrail_track.png">

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@ -1,10 +1,12 @@
/* $Id */
/** @file elrail_data.h Stores all the data for overhead wire and pylon drawing. @see elrail.c */
/** @file elrail_data.h Stores all the data for overhead wire and pylon drawing.
@see elrail.c */
#ifndef ELRAIL_DATA_H
#define ELRAIL_DATA_H
/** Tile Location group. This defines whether the X and or Y coordinate of a tile is even */
/** Tile Location group.
This defines whether the X and or Y coordinate of a tile is even */
typedef enum TLG {
XEVEN_YEVEN = 0,
XEVEN_YODD = 1,
@ -13,9 +15,9 @@ typedef enum TLG {
TLG_END
} TLG;
/** When determining the pylon configuration on the edge, two tiles are taken into account:
* the tile being drawn itself (the home tile, the one in ti->tile), and the neighbouring tile
*/
/** When determining the pylon configuration on the edge, two tiles are taken
into account: the tile being drawn itself (the home tile, the one in
ti->tile), and the neighbouring tile */
typedef enum {
TS_HOME = 0,
TS_NEIGHBOUR = 1,
@ -29,55 +31,150 @@ enum {
/** Which PPPs are possible at all on a given PCP */
static byte AllowedPPPonPCP[DIAGDIR_END] = {
1 << DIR_N | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
1 << DIR_N | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
1 << DIR_N | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
1 << DIR_N | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
};
/** Which of the PPPs are inside the tile. For the two PPPs on the tile border the following system is used:
if you rotate the PCP so that it is in the north, the eastern PPP belongs to the tile. */
/** Which of the PPPs are inside the tile. For the two PPPs on the tile border
the following system is used: if you rotate the PCP so that it is in the
north, the eastern PPP belongs to the tile. */
static byte OwnedPPPonPCP[DIAGDIR_END] = {
1 << DIR_SE | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
1 << DIR_N | 1 << DIR_SW | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_NW,
1 << DIR_NE | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S
1 << DIR_SE | 1 << DIR_S | 1 << DIR_SW | 1 << DIR_W,
1 << DIR_N | 1 << DIR_SW | 1 << DIR_W | 1 << DIR_NW,
1 << DIR_N | 1 << DIR_NE | 1 << DIR_E | 1 << DIR_NW,
1 << DIR_NE | 1 << DIR_E | 1 << DIR_SE | 1 << DIR_S
};
/** Preferred points of each trackbit. Those are the ones perpendicular to the track, plus the point in
extension of the track (to mark end-of-track).*/
/** Maps a track bit onto two PCP positions */
static const DiagDirection PCPpositions[TRACK_END][2] = {
{DIAGDIR_NE, DIAGDIR_SW}, /* X */
{DIAGDIR_SE, DIAGDIR_NW}, /* Y */
{DIAGDIR_NW, DIAGDIR_NE}, /* UPPER */
{DIAGDIR_SE, DIAGDIR_SW}, /* LOWER */
{DIAGDIR_SW, DIAGDIR_NW}, /* LEFT */
{DIAGDIR_NE, DIAGDIR_SE}, /* RIGHT */
};
#define PCP_NOT_ON_TRACK 0xFF
/** Preferred points of each trackbit. Those are the ones perpendicular to the
track, plus the point in extension of the track (to mark end-of-track). PCPs
which are not on either end of the track are fully preferred.
@see PCPpositions */
static byte PreferredPPPofTrackBitAtPCP[TRACK_END][DIAGDIR_END] = {
{1 << DIR_NE | 1 << DIR_SE | 1 << DIR_NW, 0xFF, 1 << DIR_SE | 1 << DIR_SW | 1 << DIR_NW, 0xFF }, /* X */
{0xFF, 1 << DIR_NE | 1 << DIR_SE | 1 << DIR_SW, 0xFF, 1 << DIR_SW | 1 << DIR_NW | 1 << DIR_NE }, /* Y */
{1 << DIR_E | 1 << DIR_N | 1 << DIR_S, 0xFF, 0xFF, 1 << DIR_W | 1 << DIR_N | 1 << DIR_S}, /* UPPER */
{0xFF, 1 << DIR_E | 1 << DIR_N | 1 << DIR_S, 1 << DIR_W | 1 << DIR_N | 1 << DIR_S, 0xFF}, /* LOWER */
{0xFF, 0xFF, 1 << DIR_S | 1 << DIR_E | 1 << DIR_W, 1 << DIR_N | 1 << DIR_E | 1 << DIR_W}, /* LEFT */
{1 << DIR_N | 1 << DIR_E | 1 << DIR_W, 1 << DIR_S | 1 << DIR_E | 1 << DIR_W, 0xFF, 0xFF}, /* RIGHT */
};
#define NUM_IGNORE_GROUPS 3
/** In case we have a staight line, we place pylon only every two tiles, so there are certain tiles
which we ignore. A straight line is found if we have exactly two preferred points.*/
static byte IgnoredPCP[NUM_IGNORE_GROUPS][TLG_END][DIAGDIR_END] = {
{
{1 << DIR_N | 1 << DIR_S , 1 << DIR_NE | 1 << DIR_SW, 1 << DIR_NW | 1 << DIR_SE, 1 << DIR_W | 1 << DIR_E},
{0xFF , 1 << DIR_E | 1 << DIR_W, 1 << DIR_NW | 1 << DIR_SE, 1 << DIR_NE | 1 << DIR_SW},
{1 << DIR_NW | 1 << DIR_SE, 1 << DIR_NE | 1 << DIR_SW, 1 << DIR_N | 1 << DIR_S , 0xFF},
{1 << DIR_NW | 1 << DIR_SE, 0xFF , 0xFF, 1 << DIR_NE | 1 << DIR_SW}
},
{
{1 << DIR_E | 1 << DIR_W, 1 << DIR_N | 1 << DIR_S, 0xFF, 1 << DIR_E | 1 << DIR_W},
{0xFF, 0xFF, 1 << DIR_N | 1 << DIR_S, 1 << DIR_N | 1 << DIR_S},
{0xFF, 1 << DIR_E | 1 << DIR_W, 1 << DIR_E | 1 << DIR_W, 1 << DIR_N | 1 << DIR_S},
{1 << DIR_N | 1 << DIR_S, 1 << DIR_N | 1 << DIR_S, 0xFF, 1 << DIR_E | 1 << DIR_W}
},
{
{0xFF, 0xFF, 0xFF, 0xFF},
{0xFF, 0xFF, 1 << DIR_E | 1 << DIR_W, 0xFF},
{0xFF, 0xFF, 0xFF, 0xFF},
{1 << DIR_E | 1 << DIR_W, 0xFF, 0xFF, 0xFF}
{ /* X */
1 << DIR_NE | 1 << DIR_SE | 1 << DIR_NW, /* NE */
PCP_NOT_ON_TRACK, /* SE */
1 << DIR_SE | 1 << DIR_SW | 1 << DIR_NW, /* SW */
PCP_NOT_ON_TRACK /* NE */
}, { /* Y */
PCP_NOT_ON_TRACK,
1 << DIR_NE | 1 << DIR_SE | 1 << DIR_SW,
PCP_NOT_ON_TRACK,
1 << DIR_SW | 1 << DIR_NW | 1 << DIR_NE
}, { /* UPPER */
1 << DIR_E | 1 << DIR_N | 1 << DIR_S,
PCP_NOT_ON_TRACK,
PCP_NOT_ON_TRACK,
1 << DIR_W | 1 << DIR_N | 1 << DIR_S
}, { /* LOWER */
PCP_NOT_ON_TRACK,
1 << DIR_E | 1 << DIR_N | 1 << DIR_S,
1 << DIR_W | 1 << DIR_N | 1 << DIR_S,
PCP_NOT_ON_TRACK
}, { /* LEFT */
PCP_NOT_ON_TRACK,
PCP_NOT_ON_TRACK,
1 << DIR_S | 1 << DIR_E | 1 << DIR_W,
1 << DIR_N | 1 << DIR_E | 1 << DIR_W
}, { /* RIGHT */
1 << DIR_N | 1 << DIR_E | 1 << DIR_W,
1 << DIR_S | 1 << DIR_E | 1 << DIR_W,
PCP_NOT_ON_TRACK,
PCP_NOT_ON_TRACK
}
};
#undef PCP_NOT_ON_TRACK
#define NUM_IGNORE_GROUPS 3
#define NO_IGNORE 0xFF
/** In case we have a staight line, we place pylon only every two tiles,
so there are certain tiles which we ignore. A straight line is found if
we have exactly two preferred points.*/
static byte IgnoredPCP[NUM_IGNORE_GROUPS][TLG_END][DIAGDIR_END] = {
{ /* Ignore group 1 */
{ /* X even, Y even */
1 << DIR_N | 1 << DIR_S,
1 << DIR_NE | 1 << DIR_SW,
1 << DIR_NW | 1 << DIR_SE,
1 << DIR_W | 1 << DIR_E
}, { /* X even, Y odd */
0xFF,
1 << DIR_E | 1 << DIR_W,
1 << DIR_NW | 1 << DIR_SE,
1 << DIR_NE | 1 << DIR_SW
}, { /* X odd, Y even */
1 << DIR_NW | 1 << DIR_SE,
1 << DIR_NE | 1 << DIR_SW,
1 << DIR_N | 1 << DIR_S ,
0xFF
}, { /* X odd, Y odd */
1 << DIR_NW | 1 << DIR_SE,
0xFF,
0xFF,
1 << DIR_NE | 1 << DIR_SW
}
},
{ /* Ignore group 2 */
{
1 << DIR_E | 1 << DIR_W,
1 << DIR_N | 1 << DIR_S,
0xFF,
1 << DIR_E | 1 << DIR_W
}, {
0xFF,
0xFF,
1 << DIR_N | 1 << DIR_S,
1 << DIR_N | 1 << DIR_S
}, {
0xFF,
1 << DIR_E | 1 << DIR_W,
1 << DIR_E | 1 << DIR_W,
1 << DIR_N | 1 << DIR_S
}, {
1 << DIR_N | 1 << DIR_S,
1 << DIR_N | 1 << DIR_S,
0xFF,
1 << DIR_E | 1 << DIR_W
}
},
{ /* Ignore group 3 */
{
0xFF,
0xFF,
0xFF,
0xFF
}, {
0xFF,
0xFF,
1 << DIR_E | 1 << DIR_W,
0xFF
}, {
0xFF,
0xFF,
0xFF,
0xFF
}, {
1 << DIR_E | 1 << DIR_W,
0xFF,
0xFF,
0xFF
}
}
};
#undef NO_IGNORE
/** Which pylons can definately NOT be built */
static byte DisallowedPPPofTrackBitAtPCP[TRACK_END][DIAGDIR_END] = {
@ -89,6 +186,72 @@ static byte DisallowedPPPofTrackBitAtPCP[TRACK_END][DIAGDIR_END] = {
{1 << DIR_S | 1 << DIR_N, 1 << DIR_S | 1 << DIR_N, 0, 0, }, /* RIGHT */
};
/* This array stores which track bits can meet at a tile edge */
static const Track PPPtracks[DIAGDIR_END][TRACKS_AT_PCP] = {
{TRACK_X, TRACK_X, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_Y, TRACK_Y, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_X, TRACK_X, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_Y, TRACK_Y, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
};
/* takes each of the 8 track bits from the array above and
assigns it to the home tile or neighbour tile */
static const TileSource trackorigin[DIAGDIR_END][TRACKS_AT_PCP] = {
{TS_HOME, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME },
{TS_HOME, TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_HOME },
{TS_HOME, TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME , TS_HOME , TS_NEIGHBOUR},
{TS_HOME, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR},
};
/* Several PPPs maybe exist, here they are sorted in order of preference. */
static const Direction PPPorder[DIAGDIR_END][TLG_END][DIR_END] = { /* X - Y */
{ /* PCP 0 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_N, DIR_E, DIR_S, DIR_W}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_S, DIR_W, DIR_N, DIR_E}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_S, DIR_W, DIR_N, DIR_E}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_N, DIR_E, DIR_S, DIR_W}, /* odd - odd */
}, {/* PCP 1 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_S, DIR_E, DIR_N, DIR_W}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_N, DIR_W, DIR_S, DIR_E}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_N, DIR_W, DIR_S, DIR_E}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_S, DIR_E, DIR_N, DIR_W}, /* odd - odd */
}, {/* PCP 2 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_S, DIR_W, DIR_N, DIR_E}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_N, DIR_E, DIR_S, DIR_W}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_N, DIR_E, DIR_S, DIR_W}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_S, DIR_W, DIR_N, DIR_E}, /* odd - odd */
}, {/* PCP 3 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_N, DIR_W, DIR_S, DIR_E}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_S, DIR_E, DIR_N, DIR_W}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_S, DIR_E, DIR_N, DIR_W}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_N, DIR_W, DIR_S, DIR_E}, /* odd - odd */
}
};
/* Geometric placement of the PCP relative to the tile origin */
static const int8 x_pcp_offsets[DIAGDIR_END] = {0, 8, 15, 8};
static const int8 y_pcp_offsets[DIAGDIR_END] = {8, 15, 8, 0};
/* Geometric placement of the PPP relative to the PCP*/
static const int8 x_ppp_offsets[DIR_END] = {-3, -4, -3, 0, +3, +4, +3, 0};
static const int8 y_ppp_offsets[DIR_END] = {-3, 0, +3, +4, +3, 0, -3, -4};
/* The type of pylon to draw at each PPP */
static const SpriteID pylons_normal[] = {
SPR_PYLON_EW_N,
SPR_PYLON_Y_NE,
SPR_PYLON_NS_E,
SPR_PYLON_X_SE,
SPR_PYLON_EW_S,
SPR_PYLON_Y_SW,
SPR_PYLON_NS_W,
SPR_PYLON_X_NW
};
static const SpriteID pylons_bridge[] = {
SPR_PYLON_X_NW,
SPR_PYLON_X_SE,
SPR_PYLON_Y_NE,
SPR_PYLON_Y_SW
};
typedef struct {
SpriteID image;
int8 x_offset;
@ -237,82 +400,6 @@ typedef enum {
INVALID_CATENARY = 0xFF
} CatenarySprite;
/* This array stores which track bits can meet at a tile edge */
static const Track PPPtracks[DIAGDIR_END][TRACKS_AT_PCP] = {
{TRACK_X, TRACK_X, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_Y, TRACK_Y, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_X, TRACK_X, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
{TRACK_Y, TRACK_Y, TRACK_UPPER, TRACK_LOWER, TRACK_LEFT, TRACK_RIGHT},
};
/* takes each of the 8 track bits from the array above and
assigns it to the home tile or neighbour tile */
static const TileSource trackorigin[DIAGDIR_END][TRACKS_AT_PCP] = {
{TS_HOME, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME },
{TS_HOME, TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_HOME },
{TS_HOME, TS_NEIGHBOUR, TS_NEIGHBOUR, TS_HOME , TS_HOME , TS_NEIGHBOUR},
{TS_HOME, TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR, TS_HOME , TS_NEIGHBOUR},
};
/* Several PPPs maybe exist, here they are sorted in order of preference. */
static const Direction PPPorder[DIAGDIR_END][TLG_END][DIR_END] = { /* X - Y */
{ /* PCP 0 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_N, DIR_E, DIR_S, DIR_W}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_S, DIR_W, DIR_N, DIR_E}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_S, DIR_W, DIR_N, DIR_E}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_N, DIR_E, DIR_S, DIR_W}, /* odd - odd */
}, {/* PCP 1 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_S, DIR_E, DIR_N, DIR_W}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_N, DIR_W, DIR_S, DIR_E}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_N, DIR_W, DIR_S, DIR_E}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_S, DIR_E, DIR_N, DIR_W}, /* odd - odd */
}, {/* PCP 2 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_S, DIR_W, DIR_N, DIR_E}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_N, DIR_E, DIR_S, DIR_W}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_N, DIR_E, DIR_S, DIR_W}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_S, DIR_W, DIR_N, DIR_E}, /* odd - odd */
}, {/* PCP 3 */
{DIR_NE, DIR_NW, DIR_SE, DIR_SW, DIR_N, DIR_W, DIR_S, DIR_E}, /* evn - evn */
{DIR_NE, DIR_SE, DIR_SW, DIR_NW, DIR_S, DIR_E, DIR_N, DIR_W}, /* evn - odd */
{DIR_SW, DIR_NW, DIR_NE, DIR_SE, DIR_S, DIR_E, DIR_N, DIR_W}, /* odd - evn */
{DIR_SW, DIR_SE, DIR_NE, DIR_NW, DIR_N, DIR_W, DIR_S, DIR_E}, /* odd - odd */
}
};
/* Geometric placement of the PCP relative to the tile origin */
static const int8 x_pcp_offsets[DIAGDIR_END] = {0, 8, 15, 8};
static const int8 y_pcp_offsets[DIAGDIR_END] = {8, 15, 8, 0};
/* Geometric placement of the PPP relative to the PCP*/
static const int8 x_ppp_offsets[DIR_END] = {-3, -4, -3, 0, +3, +4, +3, 0};
static const int8 y_ppp_offsets[DIR_END] = {-3, 0, +3, +4, +3, 0, -3, -4};
/* The type of pylon to draw at each PPP */
static const SpriteID pylons_normal[] = {
SPR_PYLON_EW_N,
SPR_PYLON_Y_NE,
SPR_PYLON_NS_E,
SPR_PYLON_X_SE,
SPR_PYLON_EW_S,
SPR_PYLON_Y_SW,
SPR_PYLON_NS_W,
SPR_PYLON_X_NW
};
static const SpriteID pylons_bridge[] = {
SPR_PYLON_X_NW,
SPR_PYLON_X_SE,
SPR_PYLON_Y_NE,
SPR_PYLON_Y_SW
};
/* Maps a track bit onto two PCP positions */
static const byte PCPpositions[TRACK_END][2] = {
{0, 2}, /* X */
{1, 3}, /* Y */
{3, 0}, /* UPPER */
{1, 2}, /* LOWER */
{2, 3}, /* LEFT */
{0, 1}, /* RIGHT */
};
/* Selects a Wire (with white and grey ends) depending on whether:
a) none (should never happen)
b) the first