Geometry wars style background

[bcapecci]

I want to want a reactive background similar to that of geometry wars. Does anybody know an easy way to go about this.

[Archon68]

Could you post a link/picture?

[bcapecci]

Sure.

Video: href= here
Picture: here

[Rustygames]

Yea just have a bunch of points joined together with lines and each point moves towards the player if he's near by but each point is restricted.

Good luck

[Johnny]

I think you could achieve something like that using bitmapData and either a convolution or displacement filter.

[Rustygames]

At 11/8/09 12:24 PM, Johnny wrote: I think you could achieve something like that using bitmapData and either a convolution or displacement filter.

Ah yea that's true, that's better then my idea

[bcapecci]

Displacement filter is a great idea. Thanks

[Mahora]

ohhh...pretty..
You could also make a grid of points and use them to draw the lines (with lineto and stuff) and move the points around.

[CkGordon]

Hi, not sure if this is much help from a noob but maybe you could try and fake it by just adding the background "sucking in" animation to the explosion movie clip on a lower layer and masking off everything outside of your boundries? Sometimes the quickest and simplest can achieve the same effect as the complicated. ;)

[Johnny]

At 11/8/09 02:45 PM, CkGordon wrote: Hi, not sure if this is much help from a noob but maybe you could try and fake it by just adding the background "sucking in" animation to the explosion movie clip on a lower layer and masking off everything outside of your boundries? Sometimes the quickest and simplest can achieve the same effect as the complicated. ;)

The lines would only line up a small percentage of the time, and it would be horribly obvious that it had been cheated.

[Rustygames]

At 11/8/09 02:49 PM, Johnny wrote:

At 11/8/09 02:45 PM, CkGordon wrote: Hi, not sure if this is much help from a noob but maybe you could try and fake it by just adding the background "sucking in" animation to the explosion movie clip on a lower layer and masking off everything outside of your boundries? Sometimes the quickest and simplest can achieve the same effect as the complicated. ;)

The lines would only line up a small percentage of the time, and it would be horribly obvious that it had been cheated.

Yea it will look awful and won't be very easy, displacement filter will look cool I think and will take all of about 30 minutes

[GustTheASGuy]

How is the filter a better idea? Just render the lines in medium quality.

[Pyromaniac]

You can edit this to fit your needs possibly. Its something similar to what you need.

w = 13;
h = 10;
gw = 550 / (w - 1);
d = .7;
k = .15;
sd = 50;
showgrid = true;
dd = 0;
createEmptyMovieClip("pointHold",2);
for (i = 1; i <= h; i++) {
	for (j = 1; j <= w; j++) {
		mc = pointHold.createEmptyMovieClip("p_" + i + "_" + j, ++dd);
		mc._x = mc.ox = Stage.width / 2 - (w - 1) * gw / 2 + gw * (j - 1);
		mc._y = mc.oy = Stage.height / 2 - (h - 1) * gw / 2 + gw * (i - 1);
		mc.onEnterFrame = main;
	}
}

pointHold.onEnterFrame = function() {
	clear();
	lineStyle(.25,0xffffff,40);
	for (i = 1; i <= h; i++) {
		mc = _root.pointHold["p_" + i + "_" + "1"];
		moveTo(mc._x,mc._y);
		for (j = 2; j <= w; j++) {
			mc = _root.pointHold["p_" + i + "_" + j];
			lineStyle(.25,0xffffff,40);
			lineTo(mc._x,mc._y);
		}
	}
	for (i = 1; i <= w; i++) {
		mc = _root.pointHold["p_" + "1" + "_" + i];
		moveTo(mc._x,mc._y);
		for (j = 2; j <= h; j++) {
			mc = _root.pointHold["p_" + j + "_" + i];
			lineStyle(.25,0xffffff,40);
			lineTo(mc._x,mc._y);
		}
	}
};
function main() {
	if (this.vx == undefined) {
		this.vx = 0;
		this.vy = 0;
	}
	this.vx += (this.ox - this._x) * k;
	this.vy += (this.oy - this._y) * k;
	var dx = this._x - _root._xmouse;
	var dy = this._y - _root._ymouse;
	var dist = Math.sqrt(dx * dx + dy * dy);
	if (dist <= sd) {
		var a = Math.atan2(dy, dx);
		this.vx += (_root._xmouse + sd * Math.cos(a) - this._x) * k;
		this.vy += (_root._ymouse + sd * Math.sin(a) - this._y) * k;
	}
	this._x += (this.vx *= d);
	this._y += (this.vy *= d);
}

[bcapecci]

At 11/8/09 02:59 PM, GustTheASGuy wrote: How is the filter a better idea? Just render the lines in medium quality.

I don't know if it's so much a better idea as a more straightforward one. The previous code I was pretty lost in whereas a filter is easy. I just have to basically put it on every reactive object. If I used points I could get a better looking effect but its more difficult, I have to apply the forces of each object to the points and then restrict them.

[GustTheASGuy]

Dude it's a simple spring. You accelerate the particle in the direction it's displaced and damp it and that's it.

for (p in grid)
{
  spring (p);
  forces (p);
}

connectPoints ();

function spring (p)
{
  p.vel += strength * (p.anchor - p.pos); // these are vectors
}

function forces (p)
{
  p.vel += pixToVec (influencemap.getPixel (p.pos.x, p.pos.y));
  // use a bitmap to accumulate the displacements
  // each frame caused by player and bullets
}