# Gravity

I have programmed gravity a I could (with collision detection to make the ball bounce), but I have several problems :\r - when it should stop bouncing, well, it still does, very small bounces. I think that this is because of my function that works like that : vel = vel*0.8 + distance(ball,ground) ;\r - when the motion is too quick, the ball gets stuck IN the ground. I made it so that when the ball hits the ground, vel *= -1 ; to invert the speed. So when the motion is quick, to ball hits the bottom of the groudn, and then bounces on the top of the ground so it’s stuck.\r\rAny ideas ???\r\rpom

Gravity sucks, i want to FLY !!

So That’s what I want : A flying SuperIlyas 0] that you can control, but there must be some gravity in it !!!\r\rpom

Here’s the result. Any idea ?\rpom

hope this helps:\r<a href=http://www.danalu.com/thoriphes/gravity.swf>here</a>\rif you need to see the fla, then let me know, but all the script in the movie is seen on the swf anyway…

this site came up when i was looking for real equations:\rhttp://library.thinkquest.org/16600/\r\rit’s a great site.\r\ri made something, it’s not really based of real equations like i’d hoped, but it’s at least indicative. the slider adjusts the gravity.\r\r<EMBED src=“http://members.shaw.ca/rlinton/posts/gravity.swf” quality=high bgcolor=#FFFFFF WIDTH=300 HEIGHT=300 TYPE=“application/x-shockwave-flash”></EMBED>\r\rthe code on ball is:

``````<font color="#000070">\ronClipEvent(load){	_quality = "LOW"; // not really necessary	y = _y;	d = .985; // drag	g = .5; // gravity}onClipEvent(enterFrame){// make sure we're not stoppedif(!stp){	// if our destination is beyond the barrier, and we're going down	// i think the direction check will solve your problem	if(y+ymov>270 && ymov>0){		// if we're just looping this frame, stop		if(count<2) stp=1;		y = 270;		// invert direction with a little friction		ymov*=-d;		// reset the count		count=0;	}else{		count++;		ymov += g;		y+=ymov;		ymov *= d;	}	_y=y;}}</font>
``````

Oh supra’, my scripting god, this might be one for you:\r\rwww.friendsofed.com/books…index.html\r\rseems to be new -and expensive- haven’t had a chance to get a look yet…

Thoriphe, thank you very much, your script is clear as holy water (as always).\rSupra, I don’t understand the utility of count. Very interesting link by the way.\rEyez, that book looks awesopme. If you ever buy it (\$50 !!, @#%\$ !!), you know where to find me…\r\rpom

OK, so here’s the ultimate gravity simulation. And Supra, this one’s based on physics law. Actually, I used Thoriphe’s script to make it work since I don’t understand how yours work.\rHere’s the lowdown : mass * acceleration = sum of the forces (here : weight only)\rSo acceleration = gravity constant G\rand velocity = G*Time elapsed + original speed\rAnd you get this :

Where’s the replay?\rBy the time the page is loaded, the anim is over

Couldn’t do it… Dammit !! You got me, Austin Powers !\rAny idea how to reset a timer ?\rAustin\rOk got round it :

Why doesn’t it work when you edit and add the “custom signature” ?\rpom\rDammit !!!

I hate it !!!\rBy the way, the ball seems to float a little bit because I set the gravity to 1 instead of 10.\rpom\r\rPS : By the way, I noticed that your ball can be dragged, Supra. But it doesn’t keep its speed, it just falls down. Any idea how to solve that ?

I’m having fun, or should I say… phun ? 0] Now you can drad the ball and give it the speed you want.\rpom

here’s a modifyied version of the previous swf i made, only i’ll need to give you all the fla since the code is in numerous places.\r<a href=http://www.danalu.com/thoriphes/gravity.swf>swf</a>\r<a href=http://www.danalu.com/thoriphes/gravity.fla>fla</a>

Thanks, but I kind of managed to do it after all.\rTell me, how come your animations look good and mone look like @#%\$ ?\rpom

cool…\r\rthe count was to stop the ball from vibrating perpetually at the end of it’s bounces, kind of a hack solution.\r\reyez, cool book, but \$\$\$. geez.

i also forgot to mention, to get a clean, smooth looking animation, i recommend raising the movie’s FPS to something like 50 (which i use all the time). remember, an onClipEvent(enterFrame) is just like an animation on the timeline.

This is really awesome! I have never known how to use gravity, and I gave up on it a few months ago.\r\rCheers,\rKirupa

This is so way alot supercool! I am studying the script and thank you for it Thoriphes. So cool. \r\rpj\r:cool: