The comments have a short summary of the operational highlights.
Includes fixes for reported bugs up through 14-Dec-2006
CODE
//
// Flight Assist Example
//
// Highlights:
// - altitude-based assist (lower altitude == less assist, higher == more)
// - horizontal movement gets relatively less assist than vertical.
// - HUD color indication of movement mode
// - brown: not flying (i.e. earth)
// - green: flying w/ assist
// - white: hovering w/ assist
// - black: assist disabled
// gAssistParams enables altitude-based flight assist. Lower altitudes
// will get less momentum assist so that the client updating overhead
// is less likely to harm controllability. Plus it's a pain to collide
// with a building at high speed in a damage-enabled area.
//
// see increaseMomentumAssist() for more info
//
list gAssistParams = [ <1.1, 100, 200>, <1.25, 1000, 800>, <1.4, 10000, -1> ];
float gInc = 0.1; // The increment to add to the momentum assist parameter on the next control key event
float gMass; // current mass (assuming it's constant; can imagine a variable mass assist tho :-) )
integer gMotor = FALSE; // Indicates whether momentum assistance is on
integer gAgentInfo; // A bitmask of the agent/avi current state
integer gReqKeys; // A bitmask of the control keys required to operate
integer gReqPerms; // A bitmask of the required permissions to operate
key gWearer; // UUID of the avi who is wearing this attachment
float gMomentumAssist = 0; // The current applied momentum assist
float increaseMomentumAssist(vector pos)
{
integer iii;
integer len;
len = llGetListLength(gAssistParams);
vector aParams;
for (iii = 0; iii < len; iii++)
{
aParams = llList2Vector(gAssistParams, iii);
if (pos.z < aParams.z)
{
jump exitLoop;
}
}
@exitLoop;
if (gMomentumAssist < aParams.y)
{
gInc *= aParams.x; // increase momentum assist exponentially
// param values closer to 1 result in slower growth
gMomentumAssist += gInc;
}
else
{
gMomentumAssist = aParams.y;
}
return gMomentumAssist;
}
vector getForwardDir()
{
vector ret;
ret = <1,0,0>*llGetCameraRot(); // camera rotation leads forward direction; so use it to direct assist
ret.z = 0;
return llVecNorm(ret);
}
getPermissions()
{
if ((llGetPermissions() & gReqPerms) == gReqPerms)
{
llTakeControls(gReqKeys, TRUE, TRUE);
}
else
{
llRequestPermissions(gWearer, gReqPerms);
}
}
gotControlInput(integer held)
{
gAgentInfo = llGetAgentInfo(gWearer);
if (!(held & gReqKeys))
{
if (gAgentInfo & AGENT_FLYING)
{
state hover;
}
}
if (gAgentInfo & AGENT_FLYING)
{
if (held & gReqKeys)
{
vector p = llGetPos();
vector dir;
float assist;
assist = increaseMomentumAssist(p);
if (p.z > llGround(ZERO_VECTOR)+50.0)
{
llSetBuoyancy(1.0);
}
else
{
// For some reason, if you are below
// llGround()+50.0 meters, you will
// slowly rise to that height if you
// llSetBuoyancy(1.0). An avatar can maintain
// hover below this height w/o assist; so
// no buoyancy change.
llSetBuoyancy(0.0);
}
if (held & CONTROL_FWD)
{
dir = getForwardDir();
// flying too fast horizontally
// typically makes the avatar
// uncontrollable since lag is
// high due to heavy updates;
// Do a simple reduction of assist
assist /= 3.0;
}
else if (held & CONTROL_BACK)
{
dir = -getForwardDir();
assist /= 3.0;
}
else if (held & CONTROL_UP)
{
dir = <0,0,1>;
}
else if (held & CONTROL_DOWN)
{
dir = <0,0,-1>;
}
llPushObject(gWearer, assist*gMass*dir, ZERO_VECTOR, FALSE);
gMotor = TRUE;
}
}
}
onAttach(key avatar)
{
gWearer = avatar;
if (gWearer != NULL_KEY)
{
getPermissions();
}
}
default
{
state_entry()
{
gReqKeys = CONTROL_FWD | CONTROL_UP | CONTROL_DOWN | CONTROL_BACK;
gReqPerms = PERMISSION_TRACK_CAMERA|PERMISSION_TAKE_CONTROLS;
gMass = llGetMass();
llSetColor(<0,1,0>, ALL_SIDES);
// Check if HUD is already attached
gWearer = llGetOwner(); // for now
if (llGetAttached() != 0)
{
getPermissions();
}
llSetTimerEvent(0.1);
}
on_rez(integer param)
{
llResetScript();
}
attach(key agent)
{
onAttach(agent);
}
run_time_permissions(integer perm)
{
if (perm & PERMISSION_TAKE_CONTROLS)
{
llTakeControls(gReqKeys, TRUE, TRUE);
}
}
touch_start(integer num)
{
state disabled;
}
control(key owner, integer held, integer change)
{
gotControlInput(held);
}
timer()
{
gAgentInfo = llGetAgentInfo(gWearer);
if (!(gAgentInfo & AGENT_FLYING))
{
state landed;
}
}
}
state hover
{
state_entry()
{
llSetColor(<1,1,1>, ALL_SIDES);
gMotor = FALSE;
gMomentumAssist = 0;
gInc = 0.1;
// adjust a little for lag
llMoveToTarget(llGetPos(), 0.1);
vector pos = llGetPos();
// you can hover unassisted at ground level + 50 meters
// in fact, if you set buoyancy to 1.0 there, you will slowly
// rise to ground level + 50 meters
if (llGround(ZERO_VECTOR)+50.0 < pos.z)
{
llSetBuoyancy(1.0);
}
else
{
llSetBuoyancy(0.0);
}
llTakeControls(gReqKeys, TRUE, TRUE);
}
changed(integer what)
{
if (what & CHANGED_REGION)
{
state landed;
}
}
on_rez(integer param)
{
llResetScript();
}
at_target(integer number, vector curPos, vector targPos)
{
llStopMoveToTarget();
}
control(key owner, integer held, integer change)
{
gotControlInput(held);
state default;
}
touch_start(integer num)
{
state disabled;
}
state_exit()
{
llStopMoveToTarget();
}
}
state landed
{
state_entry()
{
llStopMoveToTarget(); // just in case
llSetBuoyancy(0.0);
llSetColor(<0.5,0.5,0.25>, ALL_SIDES);
llSetTimerEvent(0.3);
}
on_rez(integer param)
{
llResetScript();
}
attach(key agent)
{
onAttach(agent);
}
run_time_permissions(integer perm)
{
if (perm & PERMISSION_TAKE_CONTROLS)
{
llTakeControls(gReqKeys, TRUE, TRUE);
}
}
touch_start(integer num)
{
state disabled;
}
timer()
{
gAgentInfo = llGetAgentInfo(gWearer);
if (gAgentInfo & AGENT_FLYING)
{
state default;
}
}
}
state disabled
{
state_entry()
{
llSetBuoyancy(0.0);
llStopMoveToTarget(); // just in case
llSetColor(<0,0,0>, ALL_SIDES);
}
attach(key agent)
{
onAttach(agent);
}
run_time_permissions(integer perm)
{
if (perm & PERMISSION_TAKE_CONTROLS)
{
llTakeControls(gReqKeys, TRUE, TRUE);
}
}
on_rez(integer param)
{
llResetScript();
}
touch_start(integer num)
{
state landed;
}
}
