I'm trying to implement very simple swipe recognition on a touch screen using AS3. I just need to know whether the swipe is to the left, right, top, or bottom.
First question: would this be easier to do using simple MOUSE_DOWN and MOUSE_UP, and simply calculate the distance(s) moved?
Or would it be easier to do using MultiTouch?
I see code for MultiTouch showing how to implement swipe detection and getting the direction thus:
if (e.offsetY == 1) {
//User swiped towards bottom
square_mc.y += 100;
}
if (e.offsetY == -1) {
//User swiped towards top
square_mc.y -= 100;
}
if (e.offsetX == 1) {
//User swiped towards right
square_mc.x += 100;
}
if (e.offsetX == -1) {
//User swiped towards left
square_mc.x -= 100;
}
but if you need to resolve to ONE direction (that is left OR up, right OR bottom, etc), how do you do that (and if offsetX and offsetY are true offsets, why are they checking for +1 and -1 only? Or is this a function that is called often during the swipe? I'm trying to get one COMPLETE swipe).
I'm thinking skipping MultiTouch might be simpler, but would welcome feedback. Thanks!
You can answer your own question(s) by doing two things...
1 Re-read the tutorial that your code came from.. especially the section headed "Coding the gesture" http://www.republicofcode.com/tutorials/flash/as3swipegesture/
2 Just experiment and learn from observing results. For example...
but if you need to resolve to ONE direction (that is left OR.... how
do you do that?
Well what's wrong with this line in the code YOU provided if (e.offsetX == -1) { square_mc.x -= 100; }. Did you test it? Did square_mc not move left by 100 pixels when you swiped towards left direction? If it worked you have successfully "resolved" one direction, I guess. You can add the other If statements for other directions as needed.
Related
I am making a flash game and I have a game character similar to this
http://us.123rf.com/400wm/400/400/chudtsankov/chudtsankov1004/chudtsankov100400927/6906625-cartoon-character-mobster-carries-weapon.jpg
The character is able to shoot when facing left,and the bullet is shot diagonally from the direction of the gun.
However, when my character faces right, the bullet is shot from the back of the head rather than the gun itself. I did realise that when the character is facing right, the registration point is on the gun but when facing left, the registration point is on the back of her head. Could that be a problem? And how do i overcome this?
Here is my code
function shootBulletBoy():void {
var fire:myBullet2 = new myBullet2();
fire.x = GirlHero.x;
fire.y = GirlHero.y;
addChild(fire);
fire.addEventListener(Event.ENTER_FRAME, moveBullet2);
}
function moveBullet2(e:Event):void {
if (GirlHero.currentLabel == ('left')){
e.currentTarget.x += Math.cos(rads) * speed;
e.currentTarget.y += Math.sin(rads) * speed;
e.currentTarget.rotation = 265;
}
if (GirlHero.currentLabel == ('right')){
e.currentTarget.x += Math.cos(radss) * speedd;
e.currentTarget.y += Math.sin(radss) * speedd;
}}
Another issue that I am having is that when my character is facing left and shoots, the gun shoots in the left direction however if the character turns right whilst the bullet is still up in the air, my bullet all of a sudden turns in the rights direction. I don't know why its doing this.
Sorry if im asking too much. You dont have to answer both my problems, a little help would do :)
Thank you
To fix your issue with the origin of your players shoot has to do with:
fire.x = GirlHero.x;
fire.y = GirlHero.y;
You are right. the registration point will be an issue. To fix this use an if statement much like your moveBullet2 function.
if (GirlHero.currentLabel == ('left')){
fire.x = GirlHero.x + leftXOffset;
fire.y = GirlHero.y + leftYOffset;
}else if (GirlHero.currentLabel == ('right')){
fire.x = GirlHero.x + rightXOffset;
fire.y = GirlHero.y + rightYOffset;
}
The offset values will need to be played with based on you character.
For you bullet shooting problem.
your MoveBullet2() function is updating direction of you bullets while they are in the air.
Once a bullet is shot, you do not want to change its direction.
Instead in your myBullet2 Class (or in code inside myBullet2 MovieClip)
create variables rads and rotation. Then set them when you create a bullet. Then in your moveBullet2() youd have:
var b:myBullet2 = myBullet2(e.currentTarget);
b.x += Math.cos(b.rads) * speedd;
b.y += Math.sin(b.rads) * speedd;
and where you create bullet would add:
fire.rads = rads;
fire.rotation = rot;
which these values would be based on the direction character facing and where the mouse was pointing.
I have a function where I can control my character.
I also have a movieclip on the stage called assassin_table.
I want to make it so that the character can't move in the table, a.k.a make the table work like a wall.
I have this code:
if(!this.hitTestObject(_root.assassin_table))
{
if(upKeyDown)
{
gotoAndStop(4);
y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
x-=Math.sin(rotation/-180*Math.PI)*(mainSpeed +7);
}
if(!upKeyDown)
{
gotoAndStop(3);
}
}
However, if I touch the table, then I can't move at all.
I know it's because if(!this.hitTestObject(_root.assassin_table)), but I don't understand the logic behind NOT moving through objects. I'd much rather have a near pixel-perfect collision detection system, but since it's so hard to find any good info online which isn't confusing, I'll stick with hitTestObject for now :)
EDIT: Tried something, didn't really work that well.
if(!_root.assassinDead && !teleporting && this.currentFrame != 5)
{
if(this.hitbox.hitTestObject(_root.assassin_table))
{
_root.assassin_table.gotoAndStop(2);
if(this.x > _root.assassin_table.x)
{
trace("Can't move right");
canMoveRight = false;
}
if(this.x <_root.assassin_table.x)
{
trace("Can't move left");
canMoveLeft = false;
}
if(this.y > _root.assassin_table.y)
{
trace("Can't move up");
canMoveUp = false;
}
if(this.y < _root.assassin_table.y)
{
trace("Can't move down");
canMoveDown = false;
}
}
else
{
canMoveRight = true;
canMoveLeft = true;
canMoveUp = true;
canMoveDown = true;
}
}
This causes me to sometimes be able to walk through the table. I figure it's because my character can move in essentially every possible angle (since he's always facing the mouse and there are no tiles/grids).
How would I make it so that it would work with the advanced movement I have?
Moving up runs this:
y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
x-=Math.sin(rotation/-180*Math.PI)*(mainSpeed +7);
And the rotation is decided by this:
this.rotation = Math.atan2((stage.mouseY - this.y), (stage.mouseX - this.x)) * 180/ Math.PI + 90;
You should seperate your hittest functions for four different moving directions.
I mean, you shouldn't use this "hitTestObject" stuff, that only returns a boolean value "true" or "false", and that's not going to work for you.
You need a function like "testPoint(player.x, player.y);" and returns the object at the given position, so you can implement it for your game like that
if (upKeyDown && testPoint(player.x, player.y - mainSpeed +7) == null) y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
player.y - mainSpeed +7 // that checks for plus mainSpeed+7 because of trying to stop your player before it get stack inside object
Basically your logic flow should be like this:
Sample input (key press)
Move character
Check for collisions
If collision then move character to it's "outside" the object that it's touching
In your particular case, if your character is on the left of the table, and you're moving right, then first things first, you move your character. At your new position, check for any collisions. If you have a collection, then because you were moving from the left, we want to be on the left of the object that we colliding with, in this case the table, so we position our character to the left of the table.
The first part of that (checking if the character has hit the table) is called collision detection. Moving the character so that it's outside the bounds of the table is called collision response. Collision detection is a pretty big field and really depends on the type of game you're making; you can do grid-based, hit-test based (if you don't have a ton of objects), physics-based, math-based etc. Collision response can be anything and everything, depending on how you want to react to a collision - you can destroy the object (balloon on a spike), change its speed (character running through mud), bounce off it (ball off wall), or stop any further movement (character against wall).
To make things a bit easier:
Separate your systems - your input shouldn't be dependant on your collision for example. If the up key is down, just register that fact - what you do with it later (make your character move) is up to you
Separate your objects position in memory from its position on screen - this will let you move it around, react to collisions etc, and only when everything is good, update the graphics (stops things like graphics entering a wall only to jump out the next frame)
Solve for one axis at a time - e.g. collide on the x axis first, then the y
Pixel perfect collision is rarely needed :) Non-rotated boxes and circles will work a lot more than you'd think
Somewhat related - the shape of your object doesn't have to be the shape that you're colliding with - e.g. your table collision shape could just be a box; your character collision shape could just be a circle
Update
This causes me to sometimes be able to walk through the table
Assuming that we're going to collide our character and table as boxes, you need to take into account their sizes - i.e. we don't just compare the x values, but the right side of our character box against the left side of the table box etc. Something like:
// assumes objects have their anchor point in the top left - if its
// not the case, adjust as you see fit
if( char.x + char.width > table.x ) // right side of the char is overlapping the left side of the table
canMoveRight = false;
else if( char.x < table.x + table.width ) // left side of char vs right side of table
canMoveLeft = false;
// etc
When working with collisions, it's always nice to see the actual boxes, for debugging. Something like this:
var debug:Shape = new Shape;
debug.addEventListener( Event.ENTER_FRAME, function():void
{
debug.graphics.clear();
debug.graphics.lineStyle( 2.0, 0xff0000 );
// char (again assuming anchor point is top left)
debug.graphics.drawRect( char.x, char.y, char.width, char.height );
// table
debug.graphics.drawRect( table.x, table.y, table.width, table.height );
});
// add our debug. NOTE: make sure it's above everything
stage.addChild( debug );
I created a script that allows your character to move around with wall collision for every direction. How do I add gravity to it on the y-axis and still have it work the same way (like a platform game)?
I tried something like char.y-- when it hits the platform if it were just the floor, but all that does is slowly bring char up no matter where it is in the object, and once it reaches the top, it shakes like crazy.
A preview of the stage: http://puu.sh/63Y1g.png
//WALL COLLISION
if(walls.hitTestPoint(char.x-(char.width/2),char.y,true) && Key.isDown(Key.A)){
char.x+=5
}
if(walls.hitTestPoint(char.x+(char.width/2),char.y,true) && Key.isDown(Key.D)){
char.x-=5
}
if(walls.hitTestPoint(char.x,char.y-(char.height/2),true) && Key.isDown(Key.W)){
char.y+=5
}
if(walls.hitTestPoint(char.x,char.y+(char.height/2),true) && Key.isDown(Key.S)){
char.y-=5
}
//CHARACTER CONTROLS
char.x+=0;
if(Key.isDown(Key.A)){
char.x+=-5;
speed=-5;
}
if(Key.isDown(Key.D)){
char.x+=5;
speed=5;
}
if(Key.isDown(Key.W)){
char.y+=-5;
speed=5;
}
if(Key.isDown(Key.S)){
char.y+=5;
speed=5;
}
To do this really simply, something like this would suffice:
// Check if there is a floor below the char
if (!floor.hitTestPoint(char.x, char.y + (char.height/2) + 2 , true))
{
// If not, apply Gravity
char.y += 5
}
This will only apply gravity if there is no floor 2 pixels directly below the char (this will stop the jittering, feel free to try with different pixel offsets that might work better in your case), I wasn't sure how you were differentiating between the walls and floor, so replace 'floor' with how you are doing it.
===============
If you would like to add realistic accelerating gravity, you will need to add a variable to track the current vertical speed of the char, then add to that each step
eg. Each step do this instead of just adding to y
// Apply gravity
vSpeed += 5
char.y += vSpeed
But if you are going to do that you might as well start getting into vectors and more complex things, there's a lot of materials on the net for this.
I move a Sprite across the screen using the keyboard, at a rate of 10 pixels/ENTER_FRAME event fire. The issue is that, when it moves, you can see it being "redrawn" every 10 pixels, which makes it hard to look at. I haven't seen this in other Flash games.
If you look closely, you can also see this here (although at a much lower scale): http://kirill-poletaev.blogspot.com/2010/07/smooth-character-movement-using-as3.html
I want to get rid of that effect, any ideas?
If the player is at a distance of ... from the screen edge, it stops moving (by moving in the opposite direction), and the BG starts scrolling (the same visual effect can be seen).
Music in playing in the background, a minimap is updated with the player's position.
private function updater(e:Event):void
{
if(up && GlobalVars.vars.upPossible)
{
cont.y-=unit;
setu(); // Player graphics state
}
else if(down && GlobalVars.vars.downPossible)
{
cont.y+=unit;
setd(); // Player graphics state
}
else if(left && GlobalVars.vars.leftPossible)
{
cont.x-=unit;
setl(); // Player graphics state
}
else if(right && GlobalVars.vars.rightPossible)
{
cont.x+=unit;
setr(); // Player graphics state
}
else
{
ups.visible=false; downs.visible=false; rights.visible=false;
lefts.visible=false; normals.visible=true; // Player graphics state
GlobalVars.vars.scXr=0; GlobalVars.vars.scYu=0; GlobalVars.vars.scXl=0;
GlobalVars.vars.scYd=0; cont.x=int(cont.x); cont.y=int(cont.y); //Someone from the Kongregate.com forums suggested this, no visible effect
}
if((cont.x=GlobalVars.vars.maxX))
{
if(cont.x=GlobalVars.vars.maxX && right && GlobalVars.vars.canScrollR) GlobalVars.vars.scXr=1, cont.x-=unit, setr();
}
else GlobalVars.vars.scXl=0, GlobalVars.vars.scXr=0; //BG Scrolling
if((cont.y=stage.stageHeight*7.3/10))
{
if(cont.y=stage.stageHeight*7.3/10 && down && GlobalVars.vars.canScrollD) GlobalVars.vars.scYd=1, cont.y-=unit, setd();
}
else GlobalVars.vars.scYu=0, GlobalVars.vars.scYd=0; //BG Scrolling
if(cont.y>=stage.stageHeight*7.3/10 && cont.x>=GlobalVars.vars.maxX) GlobalVars.vars.minimapTr=1;
else GlobalVars.vars.minimapTr=0;
if(cont.y-unitGlobalVars.vars.sH-cont.height-3.1) GlobalVars.vars.downPossible=false;
else GlobalVars.vars.downPossible=true;
if(cont.x-unitGlobalVars.vars.sW-cont.width-3.5) GlobalVars.vars.rightPossible=false;
else GlobalVars.vars.rightPossible=true;
GlobalVars.vars.plX=cont.x; //for minimap
GlobalVars.vars.plY=cont.y;
Also, key listener functions:
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyD, false, 0, true);
stage.addEventListener(KeyboardEvent.KEY_UP, keyU, false, 0, true);
private function keyD(e:KeyboardEvent):void
{
if(e.keyCode==37 || e.keyCode==65) left=true;
if(e.keyCode==38 || e.keyCode==87) up=true;
if(e.keyCode==39 || e.keyCode==68) right=true;
if(e.keyCode==40 || e.keyCode==83) down=true;
}
private function keyU(e:KeyboardEvent):void
{
if(e.keyCode==37 || e.keyCode==65) left=false;
if(e.keyCode==38 || e.keyCode==87) up=false;
if(e.keyCode==39 || e.keyCode==68) right=false;
if(e.keyCode==40 || e.keyCode==83) down=false;
}
I've encountered some improvement by increasing the FPS to 120, and decreasing the step to 4, but it's still there. I'm fairly sure it's not a performance issue, but, rather, a movement method fault.
A couple of suggestions:
Increase the frame rate
Use a tween library (e.g. GTween) with some easing effect.
Basically, if you want the object to jump 10px to the right, don't just move it right away, let it animate to its new position with some easing effect. Additionally, if the object is still moving and the key is pressed again, you probably want to accelerate the movement a bit (but only up to a point!).
I think you're asking how to make it more smooth. Well:
If you change the movement 2px per frame, then you'll have a much smoother experience. However, the movement will see very slow. To combat this, you just increase the frame rate of your swf. I believe the maximum is 120 frames, but that should be more than enough.
I love Tweenlite, it's great for pre-defined effects. It isn't for the core of your game though so I'd use Tweenlite for UI effects but barely for ingame movements responding to user controls.
I think around 24-30 fps for games is great, that's how I set all my games. I think abit you're picky, but perhaps what you're missing is a bit of edge: a smooth start and end for the movement. In most platformers I have a similar mechanic:
You want the start of the movement to start slow, reach the normal (max) speed you define and when the player lets go of a button, it slows down back to 0. This means you need to check the speed on enter frame regardless of the button triggers (they increment the speed but aren't the only condition to change speed and move the object)
enterframe loop:
//check for each direction:
if up, y_speed++
else if down, y_speed--
else if right, x_speed++
else if left, x_speed--
else // perform a decrease:
y_speed *= .8
x_speed *= .8
// make sure we aren't past the max speed
if x_speed>max_x_speed
x_speed = max_x_speed
etc. else other direction and y_speed
// now apply the movement
object.x += x_speed
object.y += y_speed
// remove the enterframe for better performance
if math.abs(x_speed)<.1 && math.abs(y_speed)<.1
// remove enterframe for movement here, add it again next time we know we have movement (button downs related to the movement, etc.)
I would implement this in your code but your code is too crowded. Anyway otherwise, most games with these simple controls are working just like your application does.
So, I'm working on the basics of Actionscript 3; making games and such.
I designed a little space where everything is based on location of boundaries, using pixel-by-pixel movement, etc.
So far, my guy can push a box around, and stops when running into the border, or when try to the push the box when it's against the border.
So, next, I wanted to make it so when I bumped into the other box, it shot forward; a small jump sideways.
I attempted to use this (foolishly) at first:
// When right and left borders collide.
if( (box1.x + box1.width/2) == (box2.x - box2.width/2) ) {
// Nine times through
for (var a:int = 1; a < 10; a++) {
// Adds 1, 2, 3, 4, 5, 4, 3, 2, 1.
if (a <= 5) {
box2.x += a; }
else {
box2.x += a - (a - 5)*2 } } }
Though, using this in the function I had for the movement (constantly checking for keys up, etc) does this all at once.
Where should I start going about a frame-by-frame movement like that? Further more, it's not actually frames in the scene, just in the movement.
This is a massive pile of garbage, I apologize, but any help would be appreciated.
try doing something like: (note ev.target is the box that you assigned the listener to)
var boxJumpDistance:Number = 0;
function jumpBox(ev:Event){
if (boxJumpDistance<= 5) {
ev.target.x += boxJumpDistance; }
else if(boxJumpDistance<=10){
ev.target.x += boxJumpDistance - (boxJumpDistance - 5)*2
}
else{
boxJumpDistance = 0;
ev.target.removeEventListener(Event.ENTER_FRAME, jumpBox);
}
}
then instead of running the loop, just add a listener:
box2.addEventListener(Event.ENTER_FRAME, jumpBox);
although this at the moment only works for a single box at a time (as it is only using one tracking variable for the speed), what you would really want to do is have that function internally to the box class, but im unsure how your structure goes. the other option would be to make an array for the boxes movement perhaps? loop through the array every frame. boxesMoveArray[1] >=5 for box 1, etc.