Hey, guys. I'm pretty new here, and the main reason I joined (aside from loving FPA) is that I'm also pretty new to flash. I've made a sort-of working slope detection game, but I'm trouble getting the character, in this case a stick, to rotate SMOOTHLY according to what the angle of the two points around him are at.
If that's not specific enough, just ask what info you need.
well i don't know much about flash so i cant really help you on that, but i am sure other people here would love to help. you may want to post on the Introduce Yourself topic. here is a link http://www.bornegames.com/forum/topic.php?id=12 anyway hope you get an answer soon.
We have a few other slope-related topics in the Game Development forum, try taking a look at those first. That may solve your problem, but if not we're here to help.
Getting the character to rotate SMOOTHLY. For some reason, when I use it now, it shakes with its rotation, and just turns a little to far, or not far enough.
Ah, I had this problem too. The trouble is that you're checking the rotation in an enterfame, so it'll be called all the time even for the smallest adjustments, result = jittery.
I found a solution with this - http://www.gotoandplay.it/_articles/2003/07/jump_and_run.php .
He's using a different way to conventional hitTest with points but the main code's very simple to redo.
The main rotation lines of code are:
mario.t_rot = Math.atan2 ( dy , dx ) * 180 / Math.PI;
and
mario._rotation += ( mario.t_rot - mario._rotation ) /4;
Substitute the lines he's using to collide with for the 2 points you rotate between, and it could easily turn into something like
character.temporaryrotation = Math.atan2(point1._y-point2._y, point1._x-point2._x) *180 / Math.PI;
This will of course get the angle to rotate to, in the temporaryrotation variable.
Next up will be
character._rotation += ( character.temporaryrotation - character._rotation ) /4;
Here finds the difference between the character's previous rotation and its current rotation, and makes it go between the 2 with a delay of 4.
I hope this helps.
I completely agree with Niall, but I'm an efficiency freak (sorry)
character.temporaryrotation = Math.atan2(point1._y-point2._y, point1._x-point2._x) *180 / Math.PI;
character._rotation += ( character.temporaryrotation - character._rotation ) /4;
180/Math.Pi is ~57 and you can skip the next formula altogether by just dividing 57 by 4
i.e.
character._rotation += Math.atan2(point1._y-point2._y, point1._x-point2._x)* 14
the response can be made to be more immediate by increasing the 14 (no higher then 57)
or you can make it even smoother by using a smaller number
Well you could do it that way, although it's more of a round off, and with something as picky as slope detection, cutting corners isn't usually the way to go.
Nice code, anyway. I think I'll try to implement that in Inkman...
Niall, you got it perfectly. The main problem I had was that I was over complicating things. When I found out that slope detection required trig stuff, I assumed it would be confusing, and forced myself to learn it in a confusing way that I saw fit.
Thanks.
Do you mean you want the character to move in relation to his rotation, instead of the regular _x and _y coordinates?
ang = (char._rotation)*(Math.PI/180);
char._x += yspeed*Math.sin(ang);
char._y += yspeed*Math.cos(ang);
char._x += xspeed*Math.cos(ang);
char._y += xspeed*Math.sin(ang);
That's what I'm using, although it's a bit gitchy and I don't know if it's right.
you too VG?
Math.pi is horribly inefficient, if you want exactness use 57.2957795.
Your code looks like it would work just fine unless you reorient yourself midair. My engine is on a school computer, but I think I remember how it goes.
ang= char._rotation / 57.3
if (!airborne){
char._x += speed*Math.cos (ang)
char._y += speed*Math.sin (ang)
if (!(char.hitTest(ground))){
airborne=true
xv = speed*Math.cos (ang)
yv = speed*Math.sin(ang)
}
}else if (airborne){
yv += 0.4
char._y += yv
char._x += xv}
I also have some code that makes the character stick to one unit below the top of the ground, but thats pretty much the jist of it.
he basically moves either into or above the ground a bit
sounds like you guy might be a bit off centre, put 0,0 right in between his legs.
That sounds like it would work, although when I tried that, if you go over a hill, it counts as a semi-jump, and you just start walking at the same angle you were originally at, but in mid-air.
So you would need to tweak it a bit more to make it fully functional.
3.14159265358979 seems efficient enough for me within Flash...
Are you sure that your ground doesn't curve too tightly? Because if the radius of the curve is close to the height of your character it would look like he was just rotating in place. The only way to fix this would be to 'straighten' out your curves a bit. (sorry if I missed the mark completely; I didn't sleep last night)
No offense, but you did kind of miss the mark completely. As soon as the points switch which one is higher, the character freezes for a second. So basically, once the slope becomes 0 for a second, that's when it just stops moving, but the friction causes it to move a bit further, changing the slope. Tell me if I'm being too confusing.
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