Discussion: Prototype Car

This is a script for building and debugging ground vehicles. It is capable of slowing down for lag and sim borders, to help reduce the chances of losing the vehicle. Simply drop this script into the root prim of a vehicle, along with any sound effect.

This script assumes that the root prim has ZERO_ROTATION and assumes the presence of a sound effect on the root prim.

// Prototype Car
// (c) 2006, Tamaria Vixen @ Second Life
// This program may be modified for personal use only!  This program may
// be freely distributed so long as it is distributed as is, without
// modification.

// Change the following line to suit your vehicle.
vector SIT = <1.5,-0.9,0.9>;

// You probably don't want to change these.
string cursim = "";
string sound = "";
vector coords = ZERO_VECTOR;
integer phys = FALSE;
float motor = 0.0;

default {
// State Entry and On Rez mainly just make sure the vehicle starts in a sane state.
    state_entry() {
        llSetStatus(STATUS_SANDBOX | STATUS_DIE_AT_EDGE | STATUS_RETURN_AT_EDGE | STATUS_BLOCK_GRAB | STATUS_PHANTOM | STATUS_PHYSICS, FALSE);
        llSetStatus(STATUS_ROTATE_X | STATUS_ROTATE_Y | STATUS_ROTATE_Z, TRUE);
        llSetTimerEvent(0.0);
        llSitTarget(SIT,ZERO_ROTATION);
        llSetCameraEyeOffset(<-10.0,0.0,4.0>);
        llSetCameraAtOffset(ZERO_VECTOR);
        llStopSound();
        llSetAlpha(0.25,ALL_SIDES);

// I remove a bunch of flags because I may be using this script to debug a vehicle after breaking it with ANOTHER script!
        llSetVehicleType(VEHICLE_TYPE_CAR);
        llRemoveVehicleFlags(VEHICLE_FLAG_LIMIT_ROLL_ONLY | VEHICLE_FLAG_MOUSELOOK_STEER | VEHICLE_FLAG_MOUSELOOK_BANK | VEHICLE_FLAG_CAMERA_DECOUPLED);
        llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, ZERO_VECTOR);

        llSetVehicleFloatParam(VEHICLE_ANGULAR_DEFLECTION_TIMESCALE, 2.0);
        llSetVehicleFloatParam(VEHICLE_LINEAR_DEFLECTION_TIMESCALE, 2.0);
        llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_TIMESCALE, 0.2);
        llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_DECAY_TIMESCALE, 10);
        llSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_TIMESCALE, 0.2);
        llSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_DECAY_TIMESCALE, 1.0);
        llSetVehicleVectorParam(VEHICLE_LINEAR_MOTOR_OFFSET, ZERO_VECTOR);
        llSetVehicleVectorParam(VEHICLE_LINEAR_FRICTION_TIMESCALE, <1,1,1>);
        llSetVehicleVectorParam(VEHICLE_ANGULAR_FRICTION_TIMESCALE, <1,1,1>);
        llSetVehicleFloatParam(VEHICLE_BUOYANCY, 0.5);
        llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_EFFICIENCY, 1.0);
        llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_TIMESCALE, 1.0);
        llSetVehicleFloatParam(VEHICLE_BANKING_EFFICIENCY, 0.0);

        cursim = llGetRegionName();
        sound = llGetInventoryName(INVENTORY_SOUND,0);
    }

    on_rez(integer x) {
        llSetRot(ZERO_ROTATION);
        llResetScript();
    }

// Did an avatar stand up or sit down?  Check that here.
    changed(integer change) {
        if(change & CHANGED_LINK) {
            key agent = llAvatarOnSitTarget();
            if(agent) {
                llRequestPermissions(agent, PERMISSION_TAKE_CONTROLS);
            }
            else llResetScript();
        }
    }

// Take controls and start up reocurring events, like timers.
    run_time_permissions(integer x) {
        if(x == PERMISSION_TAKE_CONTROLS) {
            if(sound != "") llLoopSound(sound,0.1);
            llSetTimerEvent(0.25);
            llTakeControls(CONTROL_FWD | CONTROL_BACK | CONTROL_RIGHT | CONTROL_LEFT | CONTROL_ROT_RIGHT | CONTROL_ROT_LEFT | CONTROL_UP | CONTROL_DOWN, TRUE, FALSE);
            llSetAlpha(0.0,ALL_SIDES);
        }
    }

// We only concern ourselves with up arrow, down arrow, right arrow and left arrow.
// Press says whether or not a key has been pressed.
// Change says whether or not a key's state has changed.
    control(key agent, integer press, integer change) {
        if(press & CONTROL_ROT_LEFT) llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0,0,1>);
        else if (change & CONTROL_ROT_LEFT) llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0,0,0>);
        else if(press & CONTROL_ROT_RIGHT) llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0,0,-1>);
        else if (change & CONTROL_ROT_RIGHT) llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0,0,0>);

        if(press & CONTROL_FWD) motor = 10;
        else if(change & CONTROL_FWD) motor = 0;
        else if(press & CONTROL_BACK) motor = -5;
        else if(change & CONTROL_BACK) motor = 0;
    }

    timer() {
        coords = llGetPos();
        phys = llGetStatus(STATUS_PHYSICS);

// The following lines stop the vehicle if the lag is too high or a border has been crossed.
// Greatly reduces the chances of losing the vehicle or the vehicle sinking into the ground.
        if (llGetRegionName() != cursim) {
            if(phys) llSetStatus(STATUS_PHYSICS, FALSE);
            llSleep(1 - llGetRegionTimeDilation());
            cursim = llGetRegionName();
        }
        else if(llGetRegionTimeDilation() < 0.5 || llGetRegionFPS() < 5) {
            if(phys) llSetStatus(STATUS_PHYSICS, FALSE);
            llSleep(5 - (llGetRegionTimeDilation() * 5));
        }

// If the vehicle is being effected by physics, move it around.
// If it's not, try to get it 'unstuck'.
// Do the sound effects here, too!
        if (phys) {
            if(llAbs((integer)motor) > 1) llAdjustSoundVolume(1.0);
            else llAdjustSoundVolume(0.5);
            llSetVehicleVectorParam(VEHICLE_LINEAR_MOTOR_DIRECTION,<motor,0,0>);
        }
        else {
            llAdjustSoundVolume(0.5);
            llSetPos(coords + <0,0,0.25>);
            llSetStatus(STATUS_PHYSICS, TRUE);
        }
    }
}