Precise Cursor Angle Compass - Page 3

    Flash Math(object) only understands angles in radians and our MC understands angles in degrees. So the rad must be converted into degrees. 180 / (pi / rad). The number is then rounded to the lowest whole number.

//Converts radians into degrees.
deg = Math.floor(180/(Math.PI / rad));

    In trig the positive angle is counterclockwise but in Flash it is just the opposite. A negative number multiplied by another negative number will return a positive value. Which is exactly what happens during the Math.pow function, so to compensate for the negative angle we'll just change the deg into a negative number if y is less than zero. The preceeding formulas cannot calculate the value for the 180th degree, but that can be fixed. The y value needs to be rounded down to a whole number so Flash can ask y for an equals value of zero. If y equals zero and x is in the negative realm Flash can give the the deg an assignment of 180.

//Compensates for negative angle.
if(y < 0){
    deg = -deg;
}else if((Math.floor(y) == 0) && (x < 0)){
    deg = 180;
}

    These trace actions are totally optional, but very useful during the development process. When you test the movie you can bring up the values for your variables in the output window by clicking the mouse. The trace actions won't appear when the movie is placed in a browser.

onClipEvent(mouseDown){
    trace("x = " + x);
    trace("y = " + y);
    trace("hyp = " + hyp);
    trace("cos = " + cos);
    trace(deg + "o");
}