i've been making a twist on the labyrinth game and i've got my ball to move with physics but im struggling with getting it to hit the walls around it. its currently a movie clip with black walls, and ive used this code to try and stop it:
if (character.hitTestObject(walls)){
character.x = //something
character.y = //something
}
all this does is when it hits any part of the movie clip, (even the blank spaces) it moves my character,
is there any sort of code i can use to maybe detect hitting a certain colour?
One way you could do this, is to use hitTestPoint() method to test if any of the corners have hit your wall.
hitTestPoint() tests only a single location to see if that point collides with an object. This is how you could test the top left corner of your character to see if it's touching the wall :
// I am assuming that x,y is the top left corner of your character
if (wall.hitPointTest(character.x, character.y, true))
{
// top left collided with wall
{
So you could do the same for all corners, or if you want, you can determine any collision points you want to check for the character.
Depending on your level of precision, this method might work just fine for your needs. But if you want pixel perfect collision, you can check out this link :
http://www.freeactionscript.com/2011/08/as3-pixel-perfect-collision-detection/
Related
Hey I am beginner Flash Action Script 3 developer.
I am using hitTestPoint() to detect collision between a car and a stage drawing. Car is moving in the stage so I am using hitTestPoint().
There is a problem, Lets say.
Car is a square, it is actually a perfect square right now.
I am doing this:
heightHalf = car.height / 2;
widthHalf = car.width / 2;
if(level.hitTestPoint(car.x + widthHalf, car.y + heightHalf,true)){
trace( "Right Collision" );
}
It should work as, car.x + the half of its with should return the point on x-axis which is colliding and same with the y-axis. But its not working.
When my car collides with the right walls it doesn't produce error or trace, but If I move my car further out of stage(as car can go through walls) just before it can completely move out, it produces trace error just when left side is colliding with walls.
These pics should help:
Right Collision with no error: http://i.minus.com/ibqvrbNHuLTTIX.png
Error but with wrong side: http://i.minus.com/iGRNRVmCwwY4x.png
Inverting the + - signs isn't helping either.
Take notice to where the anchor point is on the car object. since you are using Flash IDE, The anchor point could be in the middle, right, or left corner.
Also you will need multiple points do to this type of hitTesting. at least one for each side of car.
If your registration point is top left, then you are hitTesting the middle point of your car. So it will only register collision when half of the car goes over the wall.
Check your registration point. When you create a new movieClip or Sprite you can select the registration point by clicking one of the 9 box on the square that comes up under the name of the Object.
I am writing now a flash game and I run into a an issue. I have a map for the game which is defined as a 2-D array, where each element represents a component of the map. The player is always in the center of the map.
The problem is when the player reaches one end of the map. Now it is empty space. I want that the player instead of seeing the empty space, to see another end of the map and in this way, the map will loo like it goes around.
So for example if the player goes to right he will eventually start seeing the the left side of the map and the world will look continuous.
Does anyone knows how to implement this functionality?
You could make the array 2 times and put the first one behind the second one again and than the second one behind the first etc etc..
It's done here with 2 pictures, just use the arrays instead:
//The speed of the scroll movement.
var scrollSpeed:uint = 2;
//This adds two instances of the movie clip onto the stage.
var s1:ScrollBg = new ScrollBg();
var s2:ScrollBg = new ScrollBg();
addChild(s1);
addChild(s2);
//This positions the second movieclip next to the first one.
s1.x = 0;
s2.x = s1.width;
//Adds an event listener to the stage.
stage.addEventListener(Event.ENTER_FRAME, moveScroll);
//This function moves both the images to left. If the first and second
//images goes pass the left stage boundary then it gets moved to
//the other side of the stage.
function moveScroll(e:Event):void{
s1.x -= scrollSpeed;
s2.x -= scrollSpeed;
if(s1.x < -s1.width){
s1.x = s1.width;
}else if(s2.x < -s2.width){
s2.x = s2.width;
}
}
You simply check if your player is about to get off the "right" or "left" edge of the map, and position him at the other edge. To draw a circular map, you can use the following technique: if you are about to draw a column of a number that exceeds the map's width, decrease that number by width and draw the column at resultant index; and if you are about to draw a column at index below zero, add width and draw the column at resultant index. If you are in troubles of making a hitcheck at continuous map's borders, you can employ the same trick to find neighbors. (The "circular array" is a pretty basic algorithmic problem, and is resolved in many ways already)
You have a few options here. You can do the pac-man style of just making your character pop up on the other side of the screen, but that would require you to abandon the cool bit of the character being in the middle at all times.
On to the real suggestions:
If you're not implementing your array as one solid object (i.e. making it draw individual collumns/rows at a time) then this is a no-brainer. Just have a function that returns the index of the next collumn/row, within certain bounds. Like, if your array is 40 elements wide, when it tries to draw element 41, subtract the size of the array, and make it draw element 1 instead.
If your array is one solid object (like if you drew it onto a stage object and are just manipulating that) and it's not very big, you could probably get away with drawing a total of four of them, and just having a new one cover up any whitespace that's about to appear. Like, as you approach the right edge of the first array, the second array moves to the right of it for a lawless transition.
If your array is a solid object and is very big, perhaps you could make eight buffer objects (one per edge and one per corner) that hold approximately half a screen's worth of the array. That way as you approach the right edge, you see the left edge, but then when you cross into the buffer zone, you could teleport the player to the corresponding position on the left of the array, which has the buffer for the right size. To the player, nothing has changed, but now they're on the other side of the world.
I've a problem with ROLL_OVER event listener. When I enter the empty area withing the movieclip with mouse cursor, ROLL_OVER event triggers. But I want that event trigger only when mouse cursor is on the colored area.
To Make it more clear: Think about " O " letter, when mouse cursor is between the empty area of O letter (inside of O) , event shouldn't trigger. It should trigger only when mouse curser is on the black area.
How can I implement this?
Thanks
-Ozan
PROBLEM IS SOLVED THANKS TO #Ethan Kennerly
I just want to add a few things to help people have problem same as me. In my situation I tried to make continents glow when my mouse is over them. I used the ROLL_OVER/MOUSE_OVER eventlistener to check if my mouse is over them or not. But with the data given by Ethan Kennerly I produced another way.
In Ethan Kennerly's solution, if your mouse enters the area of continent from a transparent area , it doesn't get blur effect because ROLL_OVER and MOUSE_OVER event listeners only trigger once per enters so I used MOUSE_MOVE event listener on each continent movieclips.
And for this statement:
if (isPixelTransparent(DisplayObject(event.currentTarget), new Point(stage.mouseX, stage.mouseY)) {
return;
}
add whatever is in the "ROLL_OUT or MOUSE_OUT" eventlistener function, add all of them inside this statement. But don't remove ROLL_OUT or MOUSE_OUT functions.
It sounds like the movie clip contains a shape that has transparent pixels. Transparent pixels respond to mouse over and roll over. If you could draw vector graphics that have no shapes with transparent pixels, the mouse would ignore the empty space in the movie clip's bounding box.
Yet it sounds like you need to use transparent pixels and you want the mouse to ignore them, so you could guard, like this:
private function onRollOver(event:MouseEvent):void
{
if (isPixelTransparent(DisplayObject(event.currentTarget), new Point(stage.mouseX, stage.mouseY)) {
return;
}
// respond to roll over.
}
To detect transparency, Miguel Santirso rendered the pixels and translated the coordinate space here: http://sourcecookbook.com/en/recipes/97/check-if-a-pixel-is-transparent-in-a-displayobject (Except line 38 looks on my computer like "rect" got rendered as "ct"). You could optimize that code by only drawing the pixel in question, instead of the whole image, and checking if that pixel value (getPixel32) is 0, instead of calling a hitTest. I would optimize Miguel's code like this:
public static function isPixelTransparent(objectOnStage:DisplayObject, globalPoint:Point):Boolean
{
var local:Point = objectOnStage.globalToLocal(globalPoint);
var matrix:Matrix = new Matrix();
matrix.translate(-local.x, -local.y);
var data:BitmapData = new BitmapData(1, 1, true, 0x00000000);
data.draw(object, matrix);
return 0x00000000 == data.getPixel32(0, 0);
}
By the way, if all your movie clips would have the same hit test shape, you could create a separate transparent shape that listens to the roll over. I use a transparent shape to define a custom hit test shape that is a consistent and simple shape (like a circle) when the image is a more complicate shape (like an X or an O with nothing in the middle). The custom hit test shape is a Sprite with a transparent shape. The sprite listens to the roll over. A separate mouse listener shape is also useful if your movie clip, on later frames, creates new shapes that alter the silhouette of the movie clip.
The easiest solution would be using the Interactive PNG class by Moses.
http://blog.mosessupposes.com/?p=40
Normally the clear areas of a PNG are treated as solid, which can be especially frustrating when dealing with a lot of images that overlap each other because they tend to block mouse interactions on the clips below them.
This utility fixes that so that mouse events don't occur until you
bump against a solid pixel, or a pixel of any transparency value
besides totally clear. InteractivePNG lets you set an alphaTolerance
level to determine what transparency level will register as a hit.
I am new to AS3 and I wanted to know how to make a frame Boundary in flash, I am making a platformer game. My code Logic is like :
Whenever I move with ArrowKeys Move Background invert, so if I click Left key the background will move Left. so this is not really what I want as my Player (moving avatar) will always be stick to the middle of the stage. How to make a New boundary so whenever Player go near Right end of Stage ... Background should go left as much x moved outside boundary of player.
more illustration :
http://i.imgur.com/HOw6vHI.png
if(player.x > rightBound){
map.x += rightBound - player.x;
player.x = rightBound;
}
Repeat for the other 3 sides.
I'm doing some collision detection with a circle and a square and whenever the circle comes in contact with the square it bounces away changing its X coordinate by *-1. However, the Hit Area of the circle is a square, so even when it collides with the white area around the circle , the affect still occurs.
My question is, is there a way to modify the hit area to closer resemble my circle?
Thanks
Bitmap hit testing is pixel based (instead of boundary-based, like Sprite-based hit testing), so it is inherently more precise.
Here are the Adobe docs on it.
Here is a nice tutorial on it.
And here is a nice code snippet on it:
if (firstObjectBitmapData.hitTest(new Point(firstObject.x, firstObject.y), 255, secondObjectBitmapData, new Point(secondObject.x, secondObject.y), 255))
{
trace("hit!");
}