Once you get bored with the default, you might want to try driving on some different tracks. The track can be selected using command line arguments. Use either vamos -t <track> or vamos --track==<track>, where <track>, is one of the following
You can use the trk-convert program to turn a track file for RARS (Robot Auto Racing http://rars.sourceforge.net) into a C++ track file for Vamos. The converted files usually need some adjusting, so you'll have to learn a little about Vamos track files.
Tracks are defined in XML files. Here's the beginning of a track file.
<track name="Peanut">
<!-- Material Properties -->
<sky>
<sides>textures/sky_sides.png</sides>
<top>textures/sky_top.png</top>
<bottom>textures/sky_bottom.png</bottom>
<smooth/>
</sky>
All information goes inside the track tag. The sky
section describes the sky box, which is a cube onto which a background
is mapped. The sides image is wrapped around the front, right,
back, and left sides of the sky box. The optional smooth tag
can improve the quality of the sky box images.
After the sky box, the properties of the various materials that make up the track are defined.
<material name="track" type="asphalt">
<friction>1.0</friction>
<restitution>0.1</restitution>
<rolling>1.0</rolling>
<drag>0.0</drag>
<bump-amplitude>0.01</bump-amplitude>
<bump-wavelength>100.0</bump-wavelength>
<texture>
<file>textures/track2.png</file>
<length>200.0</length>
<smooth/>
<mipmap/>
</texture>
</material>
The name is used to identify the material in other parts of the file. The type helps determine what sound is played. The type must be one of rubber, metal, asphalt, concrete, grass, gravel, or dirt.
The friction tag sets the relative friction of the surface.
If, for example, you want to specify another surface that has half the
friction of asphalt, you whould set the friction value to 0.5. The
calculation of the actual frictional force involves the car.
Similarly, relative values of the coefficient of restitution, rolling
resistance, and velocity-dependent drag are set with the
restitution, rolling, and drag tags.
The bumpiness of the surface is set with the bump-amplitude,
and bump-wavelength tags. They define a sinusiodal variation
in the track's elevation. You may use whatever units you like, as
long as you're consistent. See Units.
The texture image is set in the texture section. The file is
the name of a PNG image file. The physical size that the image covers
is set with the length and width tags. In this example,
the width tag is omitted. As a result, the texture is
stretched to fit the width of the track.
The smooth and mipmap tags improve the quality of the
images, but they also reduce the frame rate.
The materials are grouped into “segments” that describe the materials for the track, kerbs, shoulders, and barriers.
<segment name="left turn">
[ wall grass kerb track kerb gravel tires ]
</segment>
The name is used to identify the segment in other parts of the file.
Inside the segment tag is an array of material names. The
material of the right-side barrier (as seen from a car traveling
forward around the track) is first.
The track is made up of road sections. Here is a simple
road section
<road segment="left turn">
<resolution>5.0</resolution>
<length>130.0</length>
<radius>160.0</radius>
</road>
The segment attribute names a list of materials defined earlier
in the file. The resolution sets the size of the quadrilateral
divisions in the road section. The smaller the resolution, the more
closely the section approximates a smooth curve. The length and width
are given in meters. However, any system of units can be used as long
as they are used consistently throughout the simulation for both
derived and fundamental quantities.
The first road section must set the width of the track and shoulder, and also the height of the barriers. These dimensions are specified as (distance, width) pairs. Any number of pairs may be specified for a given width, the program will interpolate linearly between specified points.
<!-- front straight -->
<road segment="straight pit">
<resolution>10.0</resolution>
<length>100.0</length>
<left-width>[ 0.0, 25.0 ]</left-width>
<right-width>[ 0.0, 25.0 ]</right-width>
<left-road-width>[ 0.0, 8.0 ]</left-road-width>
<right-road-width>[ 0.0, 8.0 ]</right-road-width>
<left-wall-height>2.0</left-wall-height>
<right-wall-height>2.0</right-wall-height>
<elevation>[ 20.0, 0.0 ]</elevation>
<elevation>[ 200.0, 5.0 ]</elevation>
</road>
Similarly, any number of elevation points may be specified. A spline is used to interpolate between elevation points to achieve smooth elevation changes.
Braking markers are signs that show the distance to an upcoming turn. For turns approached a high speed, markers at 150 m, 100 m, and 50 m are typically shown.
<road>
...
<braking-marker>
<file>textures/50.png</file>
<distance>50.0</distance>
<size>[ 1.4, 0.7 ]</size>
<offset>[ 2.0, 0.0 ]</offset>
<side>right</side>
</braking-marker>
<braking-marker>
<file>textures/100.png</file>
<distance>100.0</distance>
</braking-marker>
<braking-marker>
<file>textures/150.png</file>
<distance>150.0</distance>
</braking-marker>
...
</road>
Once the size and offset parameters have been set, they do not need to be specified again unless you want to use different values.
Concrete kerbs are often placed along the insides of curves, and on the opposite side at the curve exits. I'm not really sure why. Nonetheless, kerbs can be specified in the road sections.
<road>
...
<left-kerb>
<start>
<distance>10.0</distance>
<transition>
<length>4.0</length>
<width>1.0</width>
</transition>
</start>
<end>
<distance>100.0</distance>
<transition>
<length>4.0</length>
<width>1.0</width>
</transition>
</end>
<profile>[ 1.0, 0.1 ][ 3.0, 0.1 ][ 3.1, 0.0 ]</profile>
</left-kerb>
<right-kerb>
...
</right-kerb>
...
</road>
Each road section can have a left-side and a right-side kerb. A set
of coordinates of the form [ distance-from-edge-of-track,
elevation-above-track ] set the shape of the kerb in the
profile tag. A [ 0.0, 0.0 ] coordinate is inserted
automatically.
The start and end tags tell where and how the kerb
begins and ends. The distance is relative to the beginning of the
road section. The transition section tells how the ends of the
kerb are capped. In the example above, the kerb tapers down track
level and a width of 1.0 m in a distance of 4.0 m.
Once the transition length and width, and the profile are set they do
not need to be specified again unless you want to use different
values. You can use <transition/> to specify a transition with
the previously set values. For example, this kerb runs the entire
length of its road section and is capped with transitions at both
ends.
<right-kerb>
<start><transition/></start>
<end><transition/></end>
</right-kerb>
If there's no start tag, the kerb starts at the beginning of
the road section with no transition. If there's to end, the
kerb ends at the end of the road section. To make the kerb join
smoothly across two road sections, omit the end in the first
section, and omit the start in the second.
Kerbs are typically serrated. Again, I don't know why. This can be simulated by setting the bump parameters on the kerb material defined near the beginning of the track file.
Adjusting a track to make meet the beginning seamlessly is tedious.
If a <circuit/> tag is included, the program will make the
adjustments automatically. You can specify how many of the last
segments will be adjusted with the segments attribute. For
example, with <circuit segments="2"/> only the last two
segments will be changed. Note the quotes around the value (required
by the XML standard) and the trailing slash.
Allowed values for the segments tag are 0, 1, 2, and 3. The
default is 3.
In all cases (including 0) the elevation curve is forced to close.
If the track can not be closed with the specified adjustments, or the
requirements about what segments must be stright or curved, the
exception Vamos_Track::Can_Not_Close is thrown.