Animate a pendulum: Difference between revisions

=={{header|ooRexx}}==

ooRexx does not have a portable GUI, but this version is similar to the Ada version and just prints out the coordinates of the end of the pendulum.

<lang ooRexx>

pendulum = .pendulum~new(10, 30)

before = .datetime~new

do 100 -- somewhat arbitrary loop count

call syssleep .2

now = .datetime~new

pendulum~update(now - before)

before = now

say " X:" pendulum~x " Y:" pendulum~y

end

::class pendulum

::method init

expose length theta x y velocity

use arg length, theta

x = rxcalcsin(theta) * length

y = rxcalccos(theta) * length

velocity = 0

::attribute x GET

::attribute y GET

::constant g -9.81 -- acceleration due to gravity

::method update

expose length theta x y velocity

use arg duration

acceleration = self~g / length * rxcalcsin(theta)

durationSeconds = duration~microseconds / 1000000

x = rxcalcsin(theta, length)

y = rxcalccos(theta, length)

velocity = velocity + acceleration * durationSeconds

theta = theta + velocity * durationSeconds

::requires rxmath library

</lang>