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Thread: Reverse Cursor Follow

  1. #1

    Reverse Cursor Follow

    I'm looking for a tutorial or example of a reverse cursor follow script.

    So instead of having duplicate movie clips following the cursor around the Flash piece, I want to randomly place them on the stage and as the cursor passes by, they will move away, kind of like a leaf blower effect.

    Any help would be appreciated.

    Thanks.

  2. #2
    Knows where you live
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    Well if you know how to make an object more towards the mouse why not just reverse the + and -'s.
    The greatest pleasure in life is doing what people say you cannot do.
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  3. #3
    Member
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    can't you hitTest them against the player's location, and if they hit it (shapeFlag) move them away in the angle (atan2) reversed to the mouse movement?

  4. #4
    Flashmatics silentweed's Avatar
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    use reverse gravitational fields
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  5. #5
    Untitled-1.fla strille's Avatar
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    Here's a working example with comments, this will hopefully give you some ideas. To make it work, create a small movie clip, right-click on its symbol in the library and set its linkage id to particleMC:

    Code:
    createParticles(100);
    
    
    function createParticles(numOfParticles) {
    	for (var n=0;n<numOfParticles;n++) {
    		// attach a movie clip
    		var mc = _root.attachMovie("particleMC", "p"+_root.getNextHighestDepth(), _root.getNextHighestDepth());
    		// place it at a random start position
    		mc._x = random(Stage.width);
    		mc._y = random(Stage.height);
    		// set it's starting velocity to zero
    		mc.xVel = 0;
    		mc.yVel = 0;
    		// set it's starting acceleration to zero
    		mc.xAcc = 0;
    		mc.yAcc = 0;
    		// define the code that will run for each particle on every frame
    		mc.onEnterFrame = function() {
    			// move the particle
    			this._x += this.xVel;
    			this._y += this.yVel;
    			// calculate new velocity 
    			this.xVel += this.xAcc;
    			this.yVel += this.yAcc;
    			// add friction (so that the particle eventually stops if no force (acceleration) is applied
    			this.xVel *= 0.95;
    			this.yVel *= 0.95;
    
    			// if the particles moves outside the stage, let if appear on the opposite side
    			if (this._x > Stage.width) {
    				this._x -= Stage.width;
    			} else if (this._x < 0) {
    				this._x += Stage.width;
    			}
    			if (this._y > Stage.height) {
    				this._y -= Stage.height;
    			} else if (this._y < 0) {
    				this._y += Stage.height;
    			}
    
    			// calculate the acceleration, based on the mouse position
    			// this is something you don't have to do every frame, 
    			// to speed up the code, you could run it say every 3:rd frame
    			this.calcAcceleration();
    		}
    		mc.calcAcceleration = function() {
    			// find the distance in x between the mouse and the particle
    			var dx = _root._xmouse - this._x;
    			// find the distance in y between the mouse and the particle
    			var dy = _root._ymouse - this._y;
    			
    			// if the distance is more than half the stage,
    			// the force should wrap so the mouse can affect
    			// particles near the opposite edge
    			// (this is so that when the mouse is near the right stage edge
    			// it will repell particles near the left side of the stage)
    			if (Math.abs(dx) > Stage.width/2) {
    				if (dx > 0) {
    					dx -= Stage.width;
    				} else {
    					dx += Stage.width;
    				}
    			}
    			if (Math.abs(dy) > Stage.height/2) {
    				if (dy > 0) {
    					dy -= Stage.height;
    				} else {
    					dy += Stage.height;
    				}
    			}
    			
    			// find the angle between the mouse and particle
    			var angleToMouse = Math.atan2(dy, dx);
    			// calculate the distance
    			var distance = Math.sqrt(dx*dx + dy*dy);
    			// set the acceleration to the direction away from 
    			// the mouse, and make it fainter the farther away from the mouse
    			this.xAcc = -20 * Math.cos(angleToMouse)/distance;
    			this.yAcc = -20 * Math.sin(angleToMouse)/distance;		
    		}
    	}
    }

  6. #6
    Thanks! I'll test this out this afternoon and reply again.

    I appreciate the help and suggestions from everyone.

  7. #7
    Strille,

    Thanks for the script. It was close enough to what I was looking for, that I could make a bunch of tweaks and use it. One thing that I can't seem to change though, is the fact that eventually, if the cursor is off the Flash piece, all the clips seem to float to the same point.

    I actually, wrote a quick script to detect no mouse movement for a couple of seconds that triggers a loop, adjusting the velocity and other variables, but I still can't seem to get them to not congregate.

    Any suggestions on maybe adding something in there to make them slightly repel each other? Or another suggestion possibly?

    Thanks

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