Re: Programming a natural looking swing (was Repulsion between physical and other objects)

>>
>>     AnnMarie@... wrote:
>>
>>         It is a long time since I did one and mine was a vertical
>>         motion but from memory, here is an outline on how to go about
>> it.
>>
>>         The program has two segments.  The first to generate a list of
>>         numbers that runs only if you change swing parameters.
>>         This list of numbers is used by the second program segment
>>         that moves the swing.
>>         For the first part that generates the data list:-
>>         You decide how many steps you want to do from peak to peak on
>>         the swing.
>>         This can be user-setable if you want to adjust smoothness.
>>         Divide 180 degrees by this number to get the step angle for
>>         looking up.
>>         Start at 90 degrees and step to -90 degrees (converted to
>>         radians) and look up the llSin() of these angles and put them
>>         in a list.
>>         This will give you a list of numbers starting at +1 and ending
>>         at -1.
>>         You now step through this list to create a second list.
>>         You need to scale and convert the numbers from +1 through -1
>>         to an angle for llSetRot().
>>         So +1 will correspond to the highest point on the swing, say
>>         35 degrees (which can be user adjustable too).
>>         zero will correspond to swing vertical
>>         -1 corresponds to swing back 35 degrees, all converted to
>> radians.
>>
>>         You run this segment as needed to create the working list that
>>         contains the angles that are plugged into llSetRot() only on
>>         rez, or when user wants to change one of the parameters.
>>
>>         To run the swing have it sit at half way through the list
>>         (vertical) if you want it to be able to stop.
>>         When it starts, step through the list using a timer set to
>>         total swing time divided by the number of steps (can be user
>>         adjustable).
>>         You will be stepping from mid point on the list to the bottom,
>>         then reverse and step through to the top, then reverse again.
>>         On each step put the list angle value into llSetRot().
>>
>>         Although it is not physical, there is some smoothing built
>>         into llSetRot() changes, they don't move instantaneoulsy so
>>         experiment to find the minimum number of steps that looks
>>         smooth and reduces computing overhead.
>>
>>         If you want to get REALLY fancy, you can let the swing
>>         accelerate/decelerate on start/stop by changing the 35 degree
>>         angle in increasing/decreasing steps from/to zero,
>>         recalculating the angle list each time.
>>
>>         I'm sure the above could be written to calculate the angles on
>>         the fly instead of using the list look-up but I did it this
>>         way.  It is easier to understand and is probably less
>>         processing load on the sim computer.
>>
>>         AnnMarie Otoole.
>>
>>
>>         ----- Original Message ----- From: "G" <gcanaday@...
>>         <mailto:gcanaday@...>>
>>         To: <secondlifescripters@...
>>         <mailto:secondlifescripters@...>>
>>         Sent: Thursday, September 04, 2008 11:22 AM
>>         Subject: Re: Repulsion between physical and other objects
>>
>>
>>
>>             Ann,
>>
>>             oo? How does that work? /me looks for example...
>>
>>             G
>>
>>
>>
>>
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