Moving your mouse around the page, you’ll notice the red div always points at the black div.
I remember learning this from nooflat.nu by Jamie Macdonald back in 2001-2. I spun up my custom made experimental browser to take a look… also downloaded the source…
Excuse the music I was too lazy to open iMovie and add something decent… Here is the key part of the source where I learned about atan2 for the first time 😀
//SOURCE FOR EDUCATIONAL PURPOSES, ETC.
fscommand("allowscale","false")
// FUNCTION TO CALCULATE ANGLE FROM ONE OBJECT TO ANOTHER
function calcangle (me,targetclip) {
// FIRST COMPUTE THE DISTANCES FROM THE MOVIECLIP THE FUNCTION
// IS CALLED FROM TO THE TARGET CLIP:
var deltax = me._x-targetclip._x;
var deltay = me._y-targetclip._y;
// NEXT USE THESE DISTANCES TO CALCULATE THE ANGLE BETWEEN THEM:
angle = Math.atan2(deltay, deltax);
// FINALLY CONVERT THE ANGLE FROM RADIANS TO DEGREES AND THEN RETURN THE RESULT:
angle /= (Math.pi/180);
return angle;
}
Brings back great memories…
See more stuff like this over @ Snippet Zone
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