Rolling Ball

 

Compatibilities:

Rating:

This behavior can be dropped on a bitmap ball to make it roll across a plane.

--Copyright 1999 Chuck Neal --chuck@mediamacros.com --If you find this code helpful, send me an e-mail and let me know. :-) property spriteNum, diameter, baseH, constraintSprite on getPropertyDescriptionList me   p_list = [:]   p_list.addProp(#constraintSprite, [#format : #integer, #comment : "Sprite to roll on:", #default : (the currentSpriteNum + 1)])   return p_list end on beginSprite me   diameter = sprite(spriteNum).height   baseH = sprite(spriteNum).locH end on mouseDown me   startMouseH = the mouseH   startSpriteH = sprite(spriteNum).loch   repeat while the stillDown     hOffset = the mouseH - startMouseH     newLocH = startSpriteH + hOffset     if newLocH < sprite(constraintSprite).left then       newLocH = sprite(constraintSprite).left     else if newLocH > sprite(constraintSprite).right then       newLocH = sprite(constraintSprite).right     end if     --get the rotation     percentage = (newLocH - baseH) / (diameter * pi)     sprite(spriteNum).rotation = 360 * percentage     sprite(spriteNum).locH = newLocH     updateStage   end repeat end on getBehaviorDescription me   return "This is a simple behavior for rolling a ball along a flat surface. Drop it on the bitmap sprite for the ball and assign the constraint sprite." end