Rotating Dial

Date:    Mon, 20 Feb 1995 23:25:41 +0000
From:    Peter Small <peter@GENPS.DEMON.CO.UK>
Subject: A rotating dial for Roy

On Sun, 19 Feb 1995 23:10:45
Roy Pardi <rpardi@INTERACCESS.COM> wrote :
 
>My task: I am trying to create a relationship (map) between the width of
>a sprite and the duration of a QT movie such that when the mouse enters >the
>sprite rect, the movietime is set to that point.
 
> -------Stuff deleted
>
 
>the problem here is again the relationship between
>the bounding rect and the QT duration, with the added complexity of >looping
>either way through the movie so that the sim feels like true >rotation, not
>just running the linear movie.

Your requirement to be able to rotate a Quick Time 3D object with the mouse reminded me of a dial control I once made in Hypercard.

I've just tried it out in Lingo and it works quite well.

In essence, you rotate a dial with the mouse and get a read out of the position of the dial in degrees (which you can easily translate into a suitable movieTime number). It should be quite effective for rotating your 3D object.

The demo is only 12k if you want me to Email it to you, but, it will be quite simple for you to set up for yourself.

1. Put a circle (your dial) about 100 pixels in diameter into sprite (channel) 1.
2. Put a small colored circle (your knob) about 10 pixels in diameter into sprite (channel) 2.
3. Put a display field into sprite (channel) 3. Name this field "Degrees"
4. Put the following two handlers into the frame script, then turn the knob with your mouse and see what happens.

    
   on exitFrame
     pause
   end exitFrame
    
   on mouseDown
     put the locH of sprite 1 into orH
     put the locV of sprite 1 into orV
     repeat while stillDown()
       put float((mouseH() -orH)/2) into mH
       put float((mouseV() -orV)/2) into mV
       if mv > 0 then
         if mh >0 then
           put Atan(mH /mv) into angle
           put float(the width of sprite 1 /2) into Radius
           set the loch of sprite 2 to orH + sin(angle) *radius
           set the locV of sprite 2 to orV + cos(angle) *radius
           put integer(180 -angle *180/pi()) into field "Degrees"
         else
           put Atan(mH /mv) into angle
           put the width of sprite 1 /2 into Radius
           set the loch of sprite 2 to orH + sin(angle) *radius
           set the locV of sprite 2 to orV + cos(angle) *radius
           put integer(180 -angle *180/pi()) into field "Degrees"
         end if
       end if
       if mv < 0 then
         if mh >0 then
           put Atan(mH /mv) into angle
           put the width of sprite 1 /2 into Radius
           set the loch of sprite 2 to orH - sin(angle) *radius
           set the locV of sprite 2 to orV - cos(angle) *radius
           put integer(-angle *180/pi()) into field "Degrees"
         else
           put Atan(mH /mv) into angle
           put the width of sprite 1 /2 into Radius
           set the loch of sprite 2 to orH - sin(angle) *radius
           set the locV of sprite 2 to orV - cos(angle) *radius
           put integer( 360 -angle *180/pi()) into field "Degrees"
         end if
       end if
       updateStage
     end repeat
   end
   

A similar turning dial can be arranged in Director by using casts (a set pictures of a dial face in different positions).