stk-code/data/kart_characteristics.xml

<?xml version="1.0"?>
<!-- Format
    It is possible to give relative values (factors and more) for each property.

    The format as a regex is: ([+-*/](%d+|x))*
    An empty value means no change, a value without sign or with a '-' replaces
    the previous value. If an operator prefixes the string, e.g. *1.5 (- doesn't
    work because it's a sign). x will get replaced by the previous value which
    means *1.5 is equal to x*1.5. It's also possible to combine operations:
    +1.5*20 means "add 1.5 to the previous value and then multiply by 20".
    Note that it's computed sequentially from left to right and there is no
    operator precedence. Also whitespaces aren't allowed because they are used
    to split arrays.
    If you want to return the square of something use x*x or only *x.

    ATTENTION: '-' is a special case if it is the first character of a number-
    string. It means that the number is negative and NOT that the following
    float will be substracted from the base value. So if x = 10 and the string
    "-5" is processed, the result will be -5 and not the same as "x-5", which
    would result in 10 - 5 = 5.
-->
<characteristics>
    <!-- The default values that can be modified by the difficulty, karts, etc.
        The values here should also be the values of the maximum difficulty. -->
    <characteristic name="base">
        <!-- ********** Physics ********** -->

        <!-- Suspension
            stiffness: kart's suspension stiffness.
            rest: Length of suspension when at rest.
            travel-cm: maximum movement of suspension - in cm!!
            exp-string-response: dampen the suspension spring reaction
                exponentially. See
                http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=9&t=7369\&p=25236&hilit=vehicle#p25236
                for details.
            max-force: Maximum suspension force -->
        <suspension stiffness="280" rest="0.3" travel="0.29"
            exp-spring-response="false" max-force="12000" />

        <!-- Values related to stability of the chassis: damping, and reduced
                impact of roll.
            downward-impulse-factor: A speed proportional impulse applied each
                frame that pushes the vehicle onto the ground.
            track-connection-accel: An artificial force that pulls a wheel to
                the ground if its off ground. Reduces the affect if a kart loses
                contact with the ground (i.e. it then can't steer or accelerate
                anymore).
            angular-factor: Factor to change angular impulses. X and Z rotations
                are damped to avoid that karts in a collision are too easily pushed
                into a roll or pitch, which makes them topple over
            smooth-flying-impulse: apply a torque impulse to flying kart to keep
                them parallel to the ground. -->
        <stability roll-influence="0.3"
                   chassis-linear-damping="0.2"
                   chassis-angular-damping="0"
                   downward-impulse-factor="5"
                   track-connection-accel="2"
                   angular-factor="0.25 1.0 0.5"
                   smooth-flying-impulse="250" />

        <!-- Turning
            radius: The turn radius of the kart at
                a given speed. The actual steering angle is dependent on the
                wheel base of the kart: radius = wheel_base/sin(steering_angle).
                The values below define that at speed 0 the turn radius is 2, at
                speed 10 the radius is 7.5 etc.
                The actual turn radius is piece-wise linearly interpolated. This
                allows for tighter turning at lower speeds, and also avoids that
                the kart becomes too hard to control at high speed (speeds of
                higher than 23 can only be reached with powerups).
            time-full-steer: This is the amount of change in steering depending
                on current steering. So if the steering is between 0 and 0.5,
                the time-for-steering-change is 0.15. If the current steering is
                between 0.5 and 1.0, the time-for-steering-change is 0.25.
                The speed is used as dt/time-for-steering-change.
                In short: steering at less than halfway is somewhat faster,
                which should avoid oversteering (by pressing the key for too long),
                but slower when you want to steer more. Overwall with the current
                settings the expected time-to-full-steer is:
                0.5 * 0.25 + 0.5 * 0.15 = 0.2 ... which is overall the same
                time we had previously. -->
        <turn radius="0:2.0 10:7.5 25:15 45:30"
              time-full-steer="0:0.17 0.5:0.17 0.5:0.28 1.0:0.28"
              time-reset-steer="0.1" />

        <!-- Speed and acceleration
            power: The power of the kart
            max-speed: The base maximum speed of the kart in m/s
            brake-factor: Value used when braking.
            brake-time-increase: The brake force is multiplied by
                (1 + brake_time) * brake_time_increase - i.e. the longer the
                brake was pressed, the harder the kart will brake.
            max-speed-reverse-ratio is the percentage of max speed for reverse
                gear.
          -->
        <engine power="875" max-speed="25" brake-factor="15"
                brake-time-increase="6" max-speed-reverse-ratio="0.65" />

        <!-- Simulated gears
            switch-ratio defines at what ratio of the maximum
                speed what gear is selected, e.g. 0.25 means that if the speed is
                bigger or equal to 0.25 * maxSpeed then use gear 1, 0.5 means if
                the speed is bigger or equal to 0.5 x maxSpeed then gear 2.
                gear-power-increase contains the increase in max power (to simulate
                different gears), e.g. 2.5 as first entry means: 2.5 * maxPower in gear 1
                | first  | second |  third | . -->
        <gear switch-ratio="0.25 0.7 1.0" power-increase="2.2 1.7 1.3" />

        <!-- Mass of a kart -->
        <mass value="350" />

        <!-- Wheels
            damping-relaxation/compression: for bullet
            damping parameters
            Radius and width of wheel
            front-right, front-left, rear-right and rear-left give the
                position of the physics raycast wheels relative to the center of
                gravity. Default is to use the corners of the chassis to attach
                the wheels to. -->
        <wheels damping-relaxation="35"  damping-compression="5">
            <front-right position="0.38 0 0.6"   />
            <front-left  position="-0.38 0 0.6"  />
            <rear-right  position="0.38 0 -0.6"  />
            <rear-left   position="-0.38 0 -0.6" />
        </wheels>

        <!-- Friction of a kart when e.g. sliding along a wall. -->
        <friction kart-friction="0.0" />

        <!-- ********** Visuals ********** -->

        <!-- Skidding
            increase: multiplicative increase of skidding factor in each frame.
            decrease: multiplicative decrease of skidding factor in each frame.
            max: maximum skidding factor = maximum increase of steering angle.
            time-till-max: Time till maximum skidding is reached.
            visual: Additional graphical rotation of kart. The graphical rotation
                of the kart also determines the direction the kart is driving to
                when skidding is stopped.
            visual-time: How long it takes for the visual skid to reach maximum.
            revert-visual-time: how long it takes when stopping a skid to revert
                the visual skid and bring visuals and physics in sync again.
            angular-velocity: Angular velocity to be used for the kart when skidding.
            min-speed: Minimum speed a kart must have before it can skid. Must be
                >0, otherwise the kart can skid at the start of the race.
            time-till-bonus: How long a kart needs to skid in order to get a bonus.
            bonus-force: A speedup applied to the kart whick skidded for a while.
            bonus-time: How long the bonus-force is applied.
            bonus-force: Additional engine force (this is used to offset the fact
                that turning after skidding (e.g. to correct direction) often uses
                up the skid bonus).
            post-skid-rotate-factor: a factor to be used to determine how much
                the chassis of a kart should rotate to match the graphical view.
                A factor of 1 is identical, a smaller factor will rotate the kart
                less (which might  feel better).
            physical-jump-time: Time for a physical jump at the beginning of a skid.
                graphical-jump-time: Time for a graphics-only jump at the beginning
                of a skid.
            reduce-turn-min/max: The steering done by the controller (which is in
                [-1,1]) is mapped to [reduce-turn-min, reduce-turn-max] when skidding
                is active (for left turn, right turn will use [-max, -min]). The
                effect is that while you skid (say left) you can adjust the direction
                of the turn the kart is doing somewhat by steering to the left and right,
                but you will always keep on doing a left turn, just more or less. -->
        <skid increase="1.05" decrease="0.95" max="2.5" time-till-max="0.5"
              visual="1.25" visual-time="0.7" revert-visual-time="0.7"
              min-speed="10"  time-till-bonus="1.0 3.0"
              bonus-speed="4.5 6.5" bonus-time="3.0 4.0"
              bonus-force="250 350"
              physical-jump-time="0" graphical-jump-time="0.4"
              post-skid-rotate-factor="1"
              reduce-turn-min="0.2" reduce-turn-max="0.8" enabled="true" />

        <!-- Camera
            Distance between kart and camera.
            forward-up-angle: Angle between camera and plane of kart (pitch)
                when the camera is pointing forward
            backward-up-angle: Angle between camera and plane of kart (pitch)
                when the camera is pointing backwards. This is usually
                larger than the forward-up-angle, since the kart itself
                otherwise obstricts too much of the view. -->
        <camera distance="1.0" forward-up-angle="15"
                backward-up-angle="5" />

        <!-- Jump animation
            animation-time: only if the estimated time for a jump is larger
                than this value will the jump animation being
                shown. -->
       <jump animation-time="0.5" />

        <!-- Leaning related parameters, i.e. slightly leaning the karts when
             driving a fast curve.
            max: maximum leaning (i.e. when steering as much as possible at highest
                speed), in degrees.
            speed: Speed with which the leaning changes (in degree/second). -->
        <lean max="6.6" speed="15.0" />


        <!-- ********** Items ********** -->

        <!-- Anvil
            weight: The additional weight an anvil adds to a kart.
            speed-factor: The additional slowdown caused by the anvil.
            duration: The time an anvil is active. -->
        <anvil duration="2.0" weight="150"  speed-factor="0.2" />

        <!-- Parachute
            friction: The friction increase when a parachute is attached.
            duration: The time an attached parachute is active
            duration-other: The time a parachute attached from other kart works
            duration-rank-mult: The multiplier applied to the duration of the
            parachute on the 1st kart when affected by the item. Scale for
            intermediary ranks to 1.0 for the last affected.
            duration-speed-mult: Applied in all cases, multitplier to duration
            of the parachute at max-speed. Scale to 1.0 at 0 speed.
            lbound-fraction: The lower bound fraction of speed when lost will
                detach parachute. E.g. at nearly 0 speed, only 20% of speed
                need to be lost.
            ubound-fraction: The upper bound fraction of speed when lost will
                detach parachute. E.g. at max-speed 50% of speed must be lost.
            max-speed: A factor that decides the impact of rate of speed
                (distance between bounds) -->
        <parachute friction="2.0" duration="2.0" duration-other="2.6"
                   duration-rank-mult="1.35" duration-speed-mult="2.0"
                   lbound-fraction="0.8" ubound-fraction="0.5" max-speed="23" />
        <!-- Bubblegum
            duration: How long the bubblegum lasts.
            speed-fraction: To what fraction of top-speed the speed is reduced.
            torque: To rotate the kart somewhat.
            fade-in-time: How quick the slowdown takes effect.
            shield-duration: How long the bubblegum shield lasts -->
        <bubblegum duration="1" speed-fraction="0.3" torque="500" fade-in-time="0.01"
                   shield-duration="10.0" />

        <!-- Zipper
            duration: Time a zipper is active.
            force: Additional zipper force.
            speed-gain: One time additional speed.
            max-speed-increase: Additional speed allowed on top of the
                kart-specific maximum kart speed.
            fade-out-time: determines how long it takes for a zipper
                to fade out (after 'time'). -->
        <zipper duration="3.5" force="250.0" speed-gain="4.5" max-speed-increase="15"
                fade-out-time="1.0" />

        <!-- Swatter
            duration: How long can the swatter be active.
            distance: How close a kart or an item must be before it can be hit.
                      This is the square of the real distance to accelerate the
                      compution.
            squash-duration: How long a kart will remain squashed.
            squash-slowdown: Percentage of max speed that a kart is
                restricted to. -->
        <swatter duration="10" distance="9" squash-duration="5"
                 squash-slowdown="0.5" />

        <!-- Plunger and rubber band handling
            band-max-length: The maximum length of rubber band before it snaps.
            band-force: The force a plunger/rubber band applies to the kart(s).
            band-duration: The duration a rubber band acts.
            in-face-time determines how long it takes before a plunger
                in your face is removed. -->
        <plunger band-max-length="50" band-force="1500" band-duration="1"
                 band-speed-increase="7" band-fade-out-time="3"
                 in-face-time="4.5" />


        <!-- ********** Miscellaneous ********** -->

        <!-- Startup
            If a kart starts within the specified time after 'go',
            it receives the corresponding bonus from 'boost'. Those
            fields must have the same size, and must be sorted by
            increasing times. -->
        <startup time="0.3 0.5"
                 boost="6 3" />

        <!-- Rescue
            duration: How long it takes the kart to be raised.
            height: how height the kart will be raised before it is
                dropped back onto the track.
            vert rescue offset: used to raise karts a bit higher before
                releasing them on the ground after a rescue. Used to avoid
                resetting karts into the track. Not sure if this is still
                necessary. -->
        <rescue vert-offset="0.0" duration="1.2" height="2" />

        <!-- Explosion
            duration: how long it takes before the kart can drive again (this
                determines how height the kart is being thrown).
            invulnerability-time: how long a kart will be invulnerable
                after being hit by an explosion.
            radius: Kart closer to this value will be affected by
                an explosion as well.  -->
        <explosion duration="2" radius="5"
                   invulnerability-time="6" />

        <!-- Nitro
            engine-force: additional engine power
            consumption: nitro consumption - heavier characters can be set
                to need more nitro than lighter character.
            small-container: how much energy a small container gives.
            big-container: how much energy a big container gives.
            max-speed-increase: How much the speed of a kart might exceed
                its maximum speed (in m/s).
            duration: How long the increased speed will be valid after
                the kart stops using nitro (and the fade-out-time starts).
            fade-out-time: Duration during which the increased maximum
                speed due to nitro fades out.
            max: How much nitro a kart can store. -->
        <nitro engine-force="600" consumption="1" small-container="1" big-container="3"
               max-speed-increase="5" duration="1" fade-out-time="2" max="20" />

        <!-- Slipstream
            base-speed: the speed for which length and width are valid.
                They are upscaled when faster and downscaled when slower.
            length: How far behind a kart slipstream works
                (note : this helps OTHER karts)
            width: how wide slipstream works furthest away from the kart.
            inner-factor: The proportion of the slipstreaming area with
                twice faster slipstream "credits" collection.
            min-collect-time: How many seconds of sstream are needed to get a bonus
                it can be accumulated faster if in the inner quad)
            max-collect-time: How many seconds of sstream bonus can be accumulated at most
            add-power: Additional power due to sstreaming.
            min-speed: Minimum speed necessary for slipstream to take effect.
            max-speed-increase: How much the speed of the kart might exceed
                its normal maximum speed.
            duration-factor: A multiplicator to how long the higher speed lasts
                1 means it last as long the total time collected
            fade-out-time: How long the slip stream speed increase will
                gradually be reduced.  -->
        <slipstream base-speed="20" length="8" width="4" inner-factor="0.5"
                    min-collect-time="3" max-collect-time="8" add-power="300" min-speed="8"
                    max-speed-increase="5" duration-factor="1" fade-out-time="2" />
    </characteristic>

    <!-- The different difficulties (like easy, medium, hard) -->
    <difficulties>
        <characteristic name="easy">
            <engine power="*0.66" max-speed="*0.6" />
            <plunger in-face-time="3" />
        </characteristic>
        <characteristic name="medium">
            <engine power="*0.77" max-speed="*0.8" />
            <plunger in-face-time="4" />
        </characteristic>
        <characteristic name="hard">
            <engine power="*0.89" max-speed="*0.92" />
        </characteristic>
        <!-- This doesn't need to be changed because the most fast/heavy/extreme
            values should also be the default ones. -->
        <characteristic name="best" />
    </difficulties>

    <!-- The different kart types, that can be specified in the kart.xml file -->
    <kart-types>
        <characteristic name="light">
            <engine power="*0.46" max-speed="*0.92" brake-factor="*1"
                 max-speed-reverse-ratio="*0.77" />
            <gear switch-ratio="0.20 0.55 1" power-increase="5 4 3" />
            <mass value="*0.56" />
            <startup time="0.3 0.5"
                     boost="8.5 4.5" />
            <explosion time="2.1" radius="5.5"
                       invulnerability-time="7" />
            <nitro engine-force="350" max-speed-increase="4.5" duration="1.5"
                   fade-out-time="2.5" />
            <slipstream length="*0.9" collect-time="*0.9"
                        duration-factor="*1" fade-out-time="*1" />
        </characteristic>
        <characteristic name="medium">
            <engine power="*0.63" max-speed="*1" brake-factor="*0.73"
                    max-speed-reverse-ratio="*0.62" />
            <gear switch-ratio="0.30 0.7 1.0" power-increase="2.2 2.2 2.5" />
            <mass value="*0.71" />
            <startup time="0.3 0.5"
                     boost="4.2 2.6" />
            <explosion time="1.8" radius="5"
                       invulnerability-time="6" />
            <nitro engine-force="425" consumption="1.4" duration="1" />
            <slipstream duration-factor="*0.8" fade-out-time="*1" />
        </characteristic>
        <characteristic name="heavy">
            <engine power="*1" max-speed="*1" brake-factor="*0.66"
                    max-speed-reverse-ratio="*1" />
            <gear switch-ratio="0.45 0.70 1" power-increase="1.5 1.7 2.5" />
            <mass value="*1" />
            <swatter duration="10" distance="3" squash-duration="5"
                     squash-slowdown="0.5" />
            <startup time="0.3 0.5"
                     boost="3.8 2" />
            <explosion time="1.5" radius="4"
                       invulnerability-time="6" />
            <nitro engine-force="600" consumption="2" max-speed-increase="8"
                   duration="0.7" fade-out-time="1.3" />
            <slipstream length="*1.1" collect-time="*1.1"
                   duration-factor="*0.6" fade-out-time="*1" />
        </characteristic>
    </kart-types>

    <!-- Per-player settings/handicaps (or boosts) -->
    <player-characteristics>
        <characteristic name="normal" />
        <characteristic name="handicap">
            <engine power="*0.9" max-speed="*0.9" brake-factor="*0.8" brake-time-increase="*0.85" max-speed-reverse-ratio="*0.8" />
            <skid time-till-bonus="*1.2 1.0" bonus-speed="*0.9 0.8" bonus-force="*0.9 0.9" />
            <bubblegum duration="*1.5" torque="*1.5" />
            <zipper force="*0.8" speed-gain="*0.8" max-speed-increase="*0.8" />
            <swatter duration="*0.8" squash-duration="*1.3" />
            <plunger band-max-length="*0.8" band-speed-increase="*0.8" in-face-time="*1.3" />
            <startup time="*0.8 0.8" boost="*0.8 0.8" />
            <rescue duration="*1.5" />
            <nitro engine-force="*0.8" max-speed-increase="*0.9" max="*0.8" />
            <slipstream min-collect-time="*1.2" add-power="*0.9"
                        max-speed-increase="*0.9" duration-factor="*0.9" />
        </characteristic>
    </player-characteristics>
</characteristics>