Swarm Script - Printable Version

Code:
/*

Apotheus Silverman, Riptide Ramos presents...

Swarm Script

Tags: scripts, chat, collision, communications, damping, detection, ground, hover, movement, physics, primitive, region, rotation, sensor, time, vehicle, world, featured

Description: &nbsp;

// Swarm script

// by Apotheus Silverman

// with mods from Riptide Ramos

// This script is my implementation of the well-known swarm algorithm

// which can be found in numerous open-source programs.

// Due to the specifics of the SL environment, I have strayed from some

// of the traditional rules slightly. Regardless, the end effect is

// indistiguishable from the original algorithm.

This script is my implementation of the well-known swarm algorithm which can be found in numerous open-source programs.

Due to the specifics of the SL environment, I have strayed from some of the traditional rules slightly.

Regardless, the end effect is indistiguishable from the original algorithm.

&nbsp;

License:

None

http://secondlife.coolminds.org

*/



// Configurable parameters



// Determines whether or not to enable STATUS_SANDBOX.

integer sandbox = FALSE;



// Timer length

float timer_length = 0.7;



// Die after this many seconds

integer kill_time = 300;



// How much force to apply with each impulse

float force_modifier = 1.0;



// How much force to apply when repulsed by another like me

float repulse_force_modifier = 0.5;



// How much friction to use on a scale from 0 to 1.

// Note that friction takes effect each timer cycle, so the lower the timer length,

// the more the friction you specify here will take effect, thereby increasing actual

// friction applied.

float friction = 0.6;



// How much to modify rotation damping. Higher numbers produce slower rotation.

float rotation_modifier = 80;



// Does this object "swim" in air or water?

// 2 = air

// 1 = water

// 0 = both

integer flight_mode = 2;



// *** Don't change anything below unless you *really* know what you're doing ***





// Collision function

collide(vector loc) {

    vector mypos = llGetPos();

    float mass = llGetMass();

    // Apply repulse force

    vector impulse = llVecNorm(mypos - loc);

    llApplyImpulse(impulse * repulse_force_modifier * mass, FALSE);

    // Update rotation

    llLookAt(mypos + llGetVel(), mass * 0.5, mass * rotation_modifier);

}



// This function is called whether the sensor senses anything or not

sensor_any() {

    // Die after reaching kill_time

    if (kill_time != 0 && llGetTime() >= kill_time) {

        llDie();

    }



    // Get my position and mass

    vector mypos = llGetPos();



    // Check for air/water breach

    if (flight_mode == 1) {

        // water

        if (mypos.z >= llWater(mypos)) {

            collide(<mypos.x, mypos.y, mypos.z + 0.3> );

        }

    } else if (flight_mode == 2) {

        // air

        if (mypos.z <= llWater(mypos)) {

            collide(<mypos.x, mypos.y, mypos.z - 0.3> );

        }

    }

}





default {

    state_entry() {

        llSay(0, "Fishy spawned.");



        // Sandbox

        llSetStatus(STATUS_SANDBOX, sandbox);

        llSetStatus(STATUS_BLOCK_GRAB, FALSE);



        // Initialize physics behavior

        llSetBuoyancy(1.0);

        llSetStatus(STATUS_PHYSICS, TRUE);

        llSetStatus(STATUS_PHANTOM, FALSE);



        // Initialize sensor

        llSensorRepeat(llGetObjectName(), NULL_KEY, ACTIVE|SCRIPTED, 96, PI, timer_length);

    }





    collision_start(integer total_number) {

        collide(llDetectedPos(0));

    }

    land_collision_start(vector position) {

        vector mypos = llGetPos();

        collide(mypos - llGroundNormal(mypos));

    }



    no_sensor() {

        sensor_any();

    }



    sensor(integer total_number) {

        sensor_any();



        // Populate neighbors with the positions of the two nearest neighbors.

        vector mypos = llGetPos();

        float mass = llGetMass();

        list neighbors = [];

        integer i;

        

        vector v1;

        vector v2;

        float d1 = 100;

        float d2 = 100;



        for (i = 0; i < total_number; i++) {

        vector current_pos = llDetectedPos(i);

        float cur_dist = llVecDist(mypos, current_pos);

        if ( cur_dist < d1 ) {

            // Shift list down, take over top slot.

           d2 = d1;

           v2 = v1;

           d1 = cur_dist;

           v1 = current_pos;

        } else if ( cur_dist < d2 ) {

            // Replace second slot only

           d2 = cur_dist;

           v2 = current_pos;

        }

        }

        

        // Process movement



        // Apply friction

        llApplyImpulse(-(llGetVel() * friction * mass), FALSE);



        // Apply force

        if (llGetListLength(neighbors) == 2) {

            vector neighbor1 = llList2Vector(neighbors, 0);

            vector neighbor2 = llList2Vector(neighbors, 1);

            vector target = neighbor2 + ((neighbor1 - neighbor2) * 0.5);

            vector impulse = llVecNorm(target - mypos);

            llSetForce(impulse * force_modifier * mass, FALSE);

        }



        // Update rotation

        llLookAt(llGetPos() + llGetVel(), mass * 0.5, mass * rotation_modifier);

    }



    on_rez(integer start_param) {

        llResetTime();

    }

}