Hi just a few more notes about ubOde:
VEHICLE_FLAG_HOVER_GLOBAL_HEIGHT is dominant, if present
VEHICLE_HOVER_HEIGHT is a region height
Else it is a height relative to water and or terrain according to:
If VEHICLE_FLAG_HOVER_WATER_ONLY is present, water is the reference,
terrain is ignored
Else if HOVER_TERRAIN_ONLY is present terrain is used, water is
ignored.
Else it none of this two are presence the higher height of terrain
or water is used
VEHICLE_HOVER_HEIGHT can be a negative value but under the generic
constrain that objects can't go (much) underground.
VEHICLE_HOVER is disabled by setting VEHICLE_HOVER_TIMESCALE higher
than 300, not height of zero.
Regards,
Ubit
-----Original Message-----
From: opensim-users-boun...@opensimulator.org
[mailto:opensim-users-boun...@opensimulator.org] On Behalf Of AJLDuarte
Sent: Monday, May 01, 2017 16:16
To: opensim-users@opensimulator.org
Subject: Re: [Opensim-users] ubODE vs. Bullet (Ferd Frederix)
Hi,
Sorry Fred, this is not correct
VEHICLE_HOVER_HEIGHT can work with terrain, water, higher of both,
or fixed value.
This is controlled by flags:
VEHICLE_FLAG_HOVER_GLOBAL_HEIGHT
VEHICLE_FLAG_HOVER_WATER_ONLY
VEHICLE_FLAG_HOVER_TERRAIN_ONLY
Each vehicle sets defaults for this, and they be present at same
time, giving unpredictable results according to wiki
I did added a hierarchy on this flags in ubOde to reduce
unpredictability, but sure thats not like the one on bullet, if any.
So we should use llRemoveVehicleFlags() to remove the ones we don't
want, before llSetVehicleFlags();
We also have VEHICLE_FLAG_HOVER_UP_ONLY...
See http://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial and
links on it for more information.
ubOde will try to follow VEHICLE_HOVER_HEIGHT on the fly subject to
timescale and efficiency (ie how fast)
In fact it will also follow region water level changes on the fly
subject to same parameters
Also keep in mind that using llSetPos(), setvelocity, and similar
should be avoid on physics objects in active simulation, specially vehicles.
Ubit.
From: opensim-users-boun...@opensimulator.org
[mailto:opensim-users-boun...@opensimulator.org] On Behalf Of Fred Beckhusen
Sent: Monday, May 01, 2017 15:46
To: opensim-users@opensimulator.org
Subject: Re: [Opensim-users] ubODE vs. Bullet (Ferd Frederix)
Tom, I think this is a difference in implementation details. To me, Bullet
actually gets it correct. Your script is setting Hover height to go up and
down. It is effectively llSetVehicleFloatParam( VEHICLE_HOVER_HEIGHT,
HovHeightBase += .02 ); each click Up and -= 0.02 on Down, while starting
from a negative value. Zero is water height (typically 20 meters).
Water height can range from 0 to
+100 in a sim.
The problem is that VEHICLE_HOVER_HEIGHT is for use only above ground. It
is not defined in LSL by Second Life for use with negative numbers, with
additional proof of this is that zero (water height) disables it entirely.
So it is implementation specific. I would chalk this up as expected
behavior in Bullet. Try adding a float Z variable to your
VEHICLE_LINEAR_MOTOR_DIRECTION and add or subtract a small amount from the Z
(up) axis. Your axis seems suspicious. In vehicles, X is forward/back, Y is
L-R, and Z is up. Your script right and left controls are setting
VEHICLE_ANGULAR_MOTOR_DIRECTION, <0, 0, 5.0>, which is mucking around with Z
(Up). Sounds correct for a prim that rotates around Z, but not for a
vehicle. I could be wrong here. There may be a VEHICLE_REFERENCE_FRAME set
in your script elsewhere that is overriding the reference axis, so be wary
of it.
Also, take a look at the function llWater(), and think about doing this:
vector water = llWater(ZERO_VECTOR);
HovHeightBase += water.z - 20;
This will handle sims where water is at a different level.
regards and good luck:\
Ferd Frederix/Fred Beckhusen
On 2017-05-01 5:20 AM, opensim-users-requ...@opensimulator.org wrote:
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Today's Topics:
1. ubODE vs. Bullet (tring...@gmail.com)
2. Re: ubODE vs. Bullet (AJLDuarte)
----------------------------------------------------------------------
Message: 1
Date: Sun, 30 Apr 2017 23:27:37 -0400
From: <tring...@gmail.com>
To: "OS-Opensim Users" <opensim-users@opensimulator.org>
Subject: [Opensim-users] ubODE vs. Bullet
Message-ID: <65ED585961044A12B8C19EA5984238E3@TomsDesktop>
Content-Type: text/plain; charset="utf-8"
I am working on a script for a submarine and am having issues with it
working fine in ubode but will not dive or surface in Bullet physics.
Here are the primary items that are involved with the physics.
This is the initial settings the object is set with.
set_engine(){
llSetVehicleType(VEHICLE_TYPE_BOAT);
llSetVehicleFloatParam(VEHICLE_LINEAR_DEFLECTION_TIMESCALE, 0.5);
llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_TIMESCALE, 0.1);
llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_DECAY_TIMESCALE, 0.1);
llSetVehicleFloatParam(VEHICLE_LINEAR_DEFLECTION_EFFICIENCY, 0.80);
llSetVehicleVectorParam(VEHICLE_LINEAR_FRICTION_TIMESCALE, <1, 1, 1>);
llSetVehicleFloatParam(VEHICLE_ANGULAR_DEFLECTION_EFFICIENCY, 0.2);
llSetVehicleFloatParam(VEHICLE_ANGULAR_DEFLECTION_TIMESCALE, 1.0);
llSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_TIMESCALE, 0.5);
llSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_DECAY_TIMESCALE, 0.2);
llSetVehicleVectorParam(VEHICLE_ANGULAR_FRICTION_TIMESCALE, <0.1, 0.1,
0.1>);
llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_EFFICIENCY, 0.5);
llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_TIMESCALE, 1.0);
llSetVehicleFloatParam( VEHICLE_HOVER_HEIGHT, 0.0); // set ball at water
surface
llSetVehicleFloatParam( VEHICLE_HOVER_EFFICIENCY, 0.5 );
llSetVehicleFloatParam( VEHICLE_HOVER_TIMESCALE, 1.0 ); }
These are the controls and they work fine in ubODE, but CONTROL_UP and
CONTROL_DOWN do nothing in Bullet.
control(key id, integer level, integer edge)
{
float gForwardThrust; // variable for forward thrust
float gReverseThrust = -1.5; // reverse thrust backup speed
if(level & CONTROL_FWD)
{
Swimming();
gForwardThrust = 3; // normal forward speed
vTarget = llGetPos(); // get our current position
// if near region edge, slow down
if (vTarget.x > xlimit || vTarget.x < gGuard || vTarget.y >
ylimit || vTarget.y < gGuard)
{
if (vTarget.x > xlimit) vTarget.x = xlimit;
if (vTarget.x < gGuard) vTarget.x = gGuard;
if (vTarget.y > xlimit) vTarget.y = ylimit;
if (vTarget.y < gGuard) vTarget.y = gGuard;
gForwardThrust = .3; // slow us down
llWhisper(0, "Approaching sim edge, drive away...");
}
if ( vTarget.z < (llGround ( ZERO_VECTOR ) + 0.35) )
{ // too shallow and going to collide with land
gForwardThrust = .05; // slow us down
llWhisper(0, "Too shallow, drive away...");
}
llSetVehicleVectorParam(VEHICLE_LINEAR_MOTOR_DIRECTION,
<gForwardThrust,0,0>);
}
if(level & CONTROL_BACK)
{
llSetVehicleVectorParam(VEHICLE_LINEAR_MOTOR_DIRECTION,
<gReverseThrust,0,0>); // back us up
return;
}
if(level & (CONTROL_UP))
{
HovHeightBase = HovHeightBase + 0.02;
llSetVehicleFloatParam( VEHICLE_HOVER_HEIGHT, HovHeightBase);
}
if(level & (CONTROL_DOWN))
{
HovHeightBase = HovHeightBase - 0.02;
llSetVehicleFloatParam( VEHICLE_HOVER_HEIGHT, HovHeightBase);
}
if(level & (CONTROL_RIGHT|CONTROL_ROT_RIGHT))
llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0, 0,-5.0>);
if(level & (CONTROL_LEFT|CONTROL_ROT_LEFT))
llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0, 0, 5.0>);
if(edge & ~level & (CONTROL_FWD|CONTROL_BACK)) Treading();
}
I might add this is actually from my swim ball script which also works just
fine in ubODE but fails in Bullet on the dive and surface actions.
In bullet nothing at all happens.
Is this a bug in opensim? I know it is expected a script that works in one
physics engine is suppose to work in the other physics engines as well.
Not being an expert at script writing, it is possible I stumbled into doing
something wrong that ubODE can deal with and Bullet can?t.
Tom
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