The online racing simulator
LYT FILES : Live for Speed 0.6H
=========

Layout File Format for the Live for Speed Racing Simulator.
This document refers to the .LYT files created in the Autocross Editor.
The OBJECT BLOCK is also used in the related InSim packets.


Changes from 0.6B to 0.6H :
===========================
Floating objects allowed
Added custom start positions
Adjustable concrete objects included
Zchar changed to Zbyte - negative values no longer used
Index 255 now refers only to route checkers
Index 254 now refers to a restricted area
Changes to Flags byte in NOTE1 below
The flags byte in the file header has also changed


TYPES :
=======

1) short : 16 bit signed integer
2) word  : 16 bit unsigned
3) char  : 8 bit signed
4) byte  : 8 bit unsigned


FILE DESCRIPTION :
==================

num   unit    offset  description
---   ----    ------  -----------

HEADER BLOCK :

6     char    0       LFSLYT              : do not read file if no match
1     byte    6       version             : do not read file if > 0
1     byte    7       revision            : do not read file if > 251
1     word    8       num added objects   : number of OBJECT BLOCKS
1     byte    10      laps                : number
1     byte    11      flags               : 7 in new files  - see NOTE4
......OBJECT BLOCKS


OBJECT BLOCK :

1     short   0       X                   : position (1 metre = 16)
1     short   2       Y                   : position (1 metre = 16)
1     byte    4       Zbyte               : height (1m = 4) - see NOTE3
1     byte    5       Flags               : various         - see NOTE1
1     byte    6       Index               : object index    - see NOTE1/5
1     byte    7       Heading             : heading         - see NOTE2


NOTE1 :
-------
For all objects EXCEPT the concrete objects AXO_CONCRETE_SLAB etc.

if (Flags & 0x80) // highest bit of Flags is set
{
    // floating object - remains at altitude specified by Zbyte
}

How to distinguish between physical objects and special control objects
like start positions, checkpoints, finish line and marshall circles.

if (Index==0) // special control object
{
    // Heading has its usual meaning

    // Flags byte :
    // bits 0 to 1 :
    // 00 = Start position (if width = 0) or finish line (if width > 0)
    // 01 = Checkpoint 1
    // 10 = Checkpoint 2
    // 11 = Checkpoint 3
    // bits 2 to 6 :
    // half width in metres (1 to 31 - shifted left by 2 bits)
}

if (Index >= 4 && Index < 192) // an object from the list in NOTE5
{
    // Heading has its usual meaning

    if (Index >= AXO_TYRE_SINGLE && Index <= AXO_TYRE_STACK4_BIG)
    {
        // Tyres - 3 bits refer to colour
        int x_num = Flags & 0x07; // BLACK, WHITE, RED, BLUE, GREEN, YELLOW
    }

    if (Index >= AXO_CHALK_LINE && Index <= AXO_CHALK_RIGHT3)
    {
        // Chalk - 2 bits refer to colour
        int x_num = info->Flags & 0x03; // WHITE, RED, BLUE, YELLOW
    }

    if (Index >= AXO_START_POSITION && Index <= AXO_PIT_START_POINT)
    {
        // Start point - 6 bits refer to position index
        int x_num = info->Flags & 0x3f; // 0 to 47 (start pos 1 to 48)
    }

    if (Index >= AXO_CONCRETE_SLAB && Index <= AXO_CONCRETE_RAMP_WALL)
    {
        // Concrete objects - always floating regardless of 0x80 bit
        // Flags byte contains various attributes depending on the object
        // In this version each concrete object has three attributes

        Attributes:

        name     bits        values

        Width  : 0x03 >> 0 : 2, 4, 8, 16
        Length : 0x0c >> 2 : 2, 4, 8, 16
        Size X : 0x03 >> 0 : 0.25, 0.5, 0.75, 1
        Size Y : 0x0c >> 2 : 0.25, 0.5, 0.75, 1
        Height : 0xf0 >> 4 : 0.25 to 4 in steps of 0.25
        Pitch  : 0xf0 >> 4 : 0 to 90 in steps of 6 degrees
        Colour : 0x03 >> 0 : grey / red / blue / yellow
        Angle  : 0xf0 >> 4 : 5.625 to 90 in steps of 5.625 deg

        Attributes used by each object:

        AXO_CONCRETE_SLAB            : Width  / Length / Pitch
        AXO_CONCRETE_RAMP            : Width  / Length / Height
        AXO_CONCRETE_WALL            : Colour / Length / Height
        AXO_CONCRETE_PILLAR          : Size X / Size Y / Height
        AXO_CONCRETE_SLAB_WALL       : Colour / Length / Pitch
        AXO_CONCRETE_RAMP_WALL       : Colour / Length / Height
        AXO_CONCRETE_SHORT_SLAB_WALL : Colour / Size Y / Pitch
        AXO_CONCRETE_WEDGE           : Colour / Length / Angle
    }
}

if (Index==254) // a marshall circle (restricted area)
{
    // Heading has its usual meaning

    // Flags byte :
    // bits 0 to 1 :
    // 00 = no marshall
    // 01 = standing marshall
    // 10 = marshall pointing left
    // 11 = marshall pointing right
    // bits 2 to 6 :
    // radius in metres (1 to 31 - shifted left by 2 bits)
}

if (Index==255) // route checker
{
    // Heading is used not for heading, but the route index

    // Flags byte :
    // bits 2 to 6 :
    // radius in metres (1 to 31 - shifted left by 2 bits)
}


NOTE2 :
-------
Heading represents 360 degrees in 256 values.

Heading = (heading_in_degrees + 180) * 256 / 360

128 : heading of zero
192 : heading of 90 degrees
0   : heading of 180 degrees
64  : heading of -90 degrees


NOTE3 :
-------
About Zbyte, the approximate altitude :

LFS does contact checks to place objects accurately on the ground.

For output purposes : Zbyte indicates the approximate altitude with a value 
from 0 to 240 (60 metres).

For input purposes : The ground check is performed with a test ray starting 
from 2 metres above Zbyte.  Using a value lower than 240 allows objects to
be placed on the road below a bridge, for example.  If you are creating
objects from scratch and you are not sure of the approximate altitude, you
can set Zbyte to its maximum value (240).  This will place the object on
the first physical surface detected below that point.


NOTE4 :
-------
If the file is saved in the most recent format, the 3 lowest bits of the
flags byte (in the file header) must be set (total value 7).

bit 0 : file does not need correction for the Blackwood scaling
bit 1 : file does not need conversion for the new object indices
bit 2 : file does not need conversion to the 0.6H file format

Some very old layouts may not have bit 0 set.
Layouts saved up to 0.5Z34 will not have bit 1 set.
Layouts saved up to 0.6G3 will not have bit 2 set.


NOTE5 :
-------
The first valid object index is 4 (AXO_CHALK_LINE).
The gaps are to allow for future objects.
Valid object indices are all less than 192.

AXO_NULL
AXO_1
AXO_2
AXO_3
AXO_CHALK_LINE
AXO_CHALK_LINE2
AXO_CHALK_AHEAD
AXO_CHALK_AHEAD2
AXO_CHALK_LEFT
AXO_CHALK_LEFT2
AXO_CHALK_LEFT3
AXO_CHALK_RIGHT
AXO_CHALK_RIGHT2
AXO_CHALK_RIGHT3
AXO_14
AXO_15
AXO_16
AXO_17
AXO_18
AXO_19
AXO_CONE_RED
AXO_CONE_RED2
AXO_CONE_RED3
AXO_CONE_BLUE
AXO_CONE_BLUE2
AXO_CONE_GREEN
AXO_CONE_GREEN2
AXO_CONE_ORANGE
AXO_CONE_WHITE
AXO_CONE_YELLOW
AXO_CONE_YELLOW2
AXO_31
AXO_32
AXO_33
AXO_34
AXO_35
AXO_36
AXO_37
AXO_38
AXO_39
AXO_CONE_PTR_RED
AXO_CONE_PTR_BLUE
AXO_CONE_PTR_GREEN
AXO_CONE_PTR_YELLOW
AXO_44
AXO_45
AXO_46
AXO_47
AXO_TYRE_SINGLE
AXO_TYRE_STACK2
AXO_TYRE_STACK3
AXO_TYRE_STACK4
AXO_TYRE_SINGLE_BIG
AXO_TYRE_STACK2_BIG
AXO_TYRE_STACK3_BIG
AXO_TYRE_STACK4_BIG
AXO_56
AXO_57
AXO_58
AXO_59
AXO_60
AXO_61
AXO_62
AXO_63
AXO_MARKER_CURVE_L
AXO_MARKER_CURVE_R
AXO_MARKER_L
AXO_MARKER_R
AXO_MARKER_HARD_L
AXO_MARKER_HARD_R
AXO_MARKER_L_R
AXO_MARKER_R_L
AXO_MARKER_S_L
AXO_MARKER_S_R
AXO_MARKER_S2_L
AXO_MARKER_S2_R
AXO_MARKER_U_L
AXO_MARKER_U_R
AXO_78
AXO_79
AXO_80
AXO_81
AXO_82
AXO_83
AXO_DIST25
AXO_DIST50
AXO_DIST75
AXO_DIST100
AXO_DIST125
AXO_DIST150
AXO_DIST200
AXO_DIST250
AXO_92
AXO_93
AXO_94
AXO_95
AXO_ARMCO1
AXO_ARMCO3
AXO_ARMCO5
AXO_99
AXO_100
AXO_101
AXO_102
AXO_103
AXO_BARRIER_LONG
AXO_BARRIER_RED
AXO_BARRIER_WHITE
AXO_107
AXO_108
AXO_109
AXO_110
AXO_111
AXO_BANNER1
AXO_BANNER2
AXO_114
AXO_115
AXO_116
AXO_117
AXO_118
AXO_119
AXO_RAMP1
AXO_RAMP2
AXO_122
AXO_123
AXO_124
AXO_125
AXO_126
AXO_127
AXO_SPEED_HUMP_10M
AXO_SPEED_HUMP_6M
AXO_130
AXO_131
AXO_132
AXO_133
AXO_134
AXO_135
AXO_POST_GREEN
AXO_POST_ORANGE
AXO_POST_RED
AXO_POST_WHITE
AXO_140
AXO_141
AXO_142
AXO_143
AXO_BALE
AXO_145
AXO_146
AXO_147
AXO_RAILING
AXO_START_LIGHTS
AXO_150
AXO_151
AXO_152
AXO_153
AXO_154
AXO_155
AXO_156
AXO_157
AXO_158
AXO_159
AXO_SIGN_KEEP_LEFT
AXO_SIGN_KEEP_RIGHT
AXO_162
AXO_163
AXO_164
AXO_165
AXO_166
AXO_167
AXO_SIGN_SPEED_80
AXO_SIGN_SPEED_50
AXO_170
AXO_171
AXO_CONCRETE_SLAB
AXO_CONCRETE_RAMP
AXO_CONCRETE_WALL
AXO_CONCRETE_PILLAR
AXO_CONCRETE_SLAB_WALL
AXO_CONCRETE_RAMP_WALL
AXO_CONCRETE_SHORT_SLAB_WALL
AXO_CONCRETE_WEDGE
AXO_180
AXO_181
AXO_182
AXO_183
AXO_START_POSITION
AXO_PIT_START_POINT
AXO_PIT_STOP_BOX
AXO_187
AXO_188
AXO_189
AXO_190
AXO_191

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