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 Calculate mouse move/path angle

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T O P I C    R E V I E W
egrobler Posted - May 18 2014 : 07:20:00
Hi Everyone,

I need to allow the user to move an object with the mouse in the direction of the mouse path and rotate the object (a car for example) accordingly.

I assume it would involve code that is something like:
angle := ArcTan2(deltaX,deltaY)*180.0 / PI;

Is there an existing function/code in the ImageEn library that calculates the direction of the mouse movement?

Any tips or suggestions will be helpful.

Thanks and regards
Eric
1   L A T E S T    R E P L I E S    (Newest First)
egrobler Posted - May 18 2014 : 17:06:17
This seems to work ok:

function CalculateMouseDirection(const aStartPos, aCurrentPos : TPoint) : Integer;
{
 North      ->   0
 North-East ->  45
 East       ->  90
 South      -> 180
 West       -> 270
 NorthWest  -> 315
 etc.
}
var xDelta,yDelta : Integer;
               ex : Extended;
begin
  xDelta := aCurrentPos.X-aStartPos.X;
  yDelta := aStartPos.Y-aCurrentPos.Y;
  ex :=  (ArcTan2(xDelta, yDelta)*180) / PI;
  if ex<0 then ex := ex+360;
  Result := Round(ex);
end;