I have a movieclip.
Its current y is 0, and I want to move it to y 100.
How I'm currently doing it is
onenterframe { Y += 2 }
How would I do it that it starts off slow and ends slow but speeds up in the middle?
There are lots of ways to do this, one way is to use the Tween class that is provided by Adobe (actionscript 2 + 3)
import fl.transitions.Tween;
import fl.transitions.easing.*;
var tween:Tween;
function moveTo(targetY:Number, numberOfFrames:int) {
tween = new Tween(this, "y", Regular.easeInOut, y, targetY, numberOfFrames);
}
See the flash reference for more info
You can also use just the Regular.easeInOut function in your own onEnterFrame loop, or choose to use one of many community written tween libraries like gTween or TweenLite.
Related
I'm not sure if this is the best place to ask this question or not but I feel like I'm struggling to grasp something relatively simple and can't find any decent advice on it in relation to KorGE so if anyone can offer any assistance it would be much appreciated.
This is a a question that can relate to multiple things so I'll use a simple example to demonstrate.
Say I set up a solidRect and I want it to travel along the x coordinate by one on each update I might do something like this:
solidRect(16.0, 16.0, Colors.GREEN) {
x = 0.0;
y = 0.0;
addUpdater {
x += 1.0;
}
}
This will create a solid rectangle in the container of 16px by 16px at the position 0,0 and each update will then add 1 to the x position moving it across the screen. Now what I'd like to do is encapsulate this logic into a class in a separate file so I could do something along the lines of the following:
movingShape() {
x = 0.0,
y = 0.0,
}
My expectation being that this would create the same solid rect visible in the scene, position it a 0, 0 and then the updater would be contained within the class itself, so I can use this logic multiple times. However, whenever I do this either init the solidRect in the class or passing it through in the constructor the updater function fails to fire.
As a longer fully functioning example I'd want something along the lines of this:
suspend fun main() = Korge(width = 512.0, height=512.0, bgcolor = Colors["#2b2b2b"]) {
val sceneContainer = sceneContainer();
sceneContainer.changeTo({MyScene()});
}
class MyScene : Scene() {
override suspend fun SContainer.sceneMain() {
movingShape() {
x = 0.0;
y = 0.0;
}
}
}
How would I implement the movingShape class in this example so it works kind of how I mentioned above?
Once again, sorry, if this seems like a trivial question or could be easily answered through some Kotlin. I'm relatively new to the language mainly coming from a Java / JS / PHP background. Any help would be appreciated here? I've tried to look for a good example of this but so far have turned up empty.
I am building an HTML5 Canvas 2d game and i have some es6 classes on my project. One of them is Obstacles. What i want to do is having the ability to create a different instance of this class depending on a given type (eg. small, thick, tall etc).
What is the best way to do this?
Just add another parameter to the constructor of the class and name it type?
Or just create subclasses of the main class Obstacle by extending it (eg. SmallObstacle, TallObstacle) given a random type value?
Thanks in advance.
Your question is based around how you want to build and implement your data structures. Neither option is necessarily better than the other 100% of the time. I'll explain the pro's and con's of each below along with my personal solution. You can decide which one is more feasible for you to implement.
Option 1:
Pros:
Easy to insert into the class and deal with later in your code
Leaves your class neat and slimmer
Cons:
You have to deal with it later in your code. When initializing (maybe even when updating/rendering) your code needs to interpret what the types are and build each obstacle based on that.
Option 2:
Pros:
Makes an organized class
Not much work later in your code since you're just pulling preset specifications rather than interpreting them
Cons:
The class is much larger
You are likely to be repeating some code (although if you do it well, you won't)
My Opinion:
Personally I would skip specifying "large," "medium," "tall," "wide." Instead, I would use some logic when implementing the class and make the height and width whatever I want. You could take advantage of how one can easily specify a value while also providing a default with a function constructor.
Here is a snippet example:
class obstacle {
constructor(x, y, w=150, h=150) {
this.x = x;
this.y = y;
this.width = w; //default is 150
this.height = h; //so it's medium or something
this.sprite = ...; //etc.
}
}
// Initialize 100 obstacles :P
for (let i=0; i<100; i++) {
let x = Math.random() * scene.width;
let y = Math.random() * scene.height;
let foo = new obstacle(x, y);
/* When you want different width and height instead
of the default, construct like this:
let bar = new obstacle(x, y, width, height);
*/
}
I've got a question about libGDX collision detection. Because it's a rather specific question I have not found any good solution on the internet yet.
So, I already created "humans" that consist of different body parts, each with rectangle-shaped collision detection.
Now I want to implement weapons and skills, which for example look like this:
Skill example image
Problem
Working with rectangles in collision detections would be really frustrating for players when there are skills like this: They would dodge a skill successfully but the collision detector would still damage them.
Approach 1:
Before I started working with Libgdx I have created an Android game with a custom engine and similar skills. There I solved the problem following way:
Detect rectangle collision
Calculate overlapping rectangle section
Check every single pixel of the overlapping part of the skill for transparency
If there is any non-transparent pixel found -> Collision
That's a kind of heavy way, but as only overlapping pixels are checked and the rest of the game is really light, it works completely fine.
At the moment my skill images are loaded as "TextureRegion", where it is not possible to access single pixels.
I have found out that libGDX has a Pixmap class, which would allow such pixel checks. Problem is: having them loaded as Pixmaps additionally would 1. be even more heavy and 2. defeat the whole purpose of the Texture system.
An alternative could be to load all skills as Pixmap only. What do you think: Would this be a good way? Is it possible to draw many Pixmaps on the screen without any issues and lag?
Approach 2:
An other way would be to create Polygons with the shape of the skills and use them for the collision detection.
a)
But how would I define a Polygon shape for every single skill (there are over 150 of them)? Well after browsing a while, I found this useful tool: http://www.aurelienribon.com/blog/projects/physics-body-editor/
it allows to create Polygon shapes by hand and then save them as JSON files, readable by the libGDX application. Now here come the difficulties:
The Physics Body Editor is connected to Box2d (which I am not using). I would either have to add the whole Box2d physics engine (which I do not need at all) just because of one tiny collision detection OR I would have to write a custom BodyEditorLoader which would be a tough, complicated and time-intensive task
Some images of the same skill sprite have a big difference in their shapes (like the second skill sprite example). When working with the BodyEditor tool, I would have to not only define the shape of every single skill, but I would have to define the shape of several images (up to 12) of every single skill. That would be extremely time-intensive and a huge mess when implementing these dozens of polygon shapes
b)
If there is any smooth way to automatically generate Polygons out of images, that could be the solution. I could simply connect every sprite section to a generated polygon and check for collisions that way. There are a few problems though:
Is there any smooth tool which can generate Polygon shapes out of an image (and does not need too much time therefor)?
I don't think that a tool like this (if one exists) can directly work with Textures. It would probably need Pixmaps. It would not be needed to keep te Pixmaps loaded after the Polygon creation though. Still an extremely heavy task!
My current thoughts
I'm stuck at this point because there are several possible approaches but all of them have their difficulties. Before I choose one path and continue coding, it would be great if you could leave some of your ideas and knowledge.
There might be helpful classes and code included in libGDX that solve my problems within seconds - as I am really new at libGDX I just don't know a lot about it yet.
Currently I think I would go with approach 1: Work with pixel detection. That way I made exact collision detections possible in my previous Android game.
What do you think?
Greetings
Felix
I, personally, would feel like pixel-to-pixel collision would be overkill on performance and provide some instances where I would still feel cheated - (I got hit by the handle of the axe?)
If it were me, I would add a "Hitbox" to each skill. StreetFighter is a popular game which uses this technique. (newer versions are in 3D, but hitbox collision is still 2D) Hitboxes can change frame-by-frame along with the animation.
Empty spot here to add example images - google "Streetfighter hitbox" in the meantime
For your axe, there could be a defined rectangle hitbox along the edge of one or both ends - or even over the entire metal head of the axe.
This keeps it fairly simple, without having to mess with exact polygons, but also isn't overly performance heavy like having every single pixel being its own hitbox.
I've used that exact body editor you referenced and it has the ability to generate polygons and/or circles for you. I also made a loader for the generated JSON with the Jackson library. This may not be the answer for you since you'd have to implement box2d. But here's how how I did it anyway.
/**
* Adds all the fixtures defined in jsonPath with the name'lookupName', and
* attach them to the 'body' with the properties defined in 'fixtureDef'.
* Then converts to the proper scale with 'width'.
*
* #param body the body to attach fixtures to
* #param fixtureDef the fixture's properties
* #param jsonPath the path to the collision shapes definition file
* #param lookupName the name to find in jsonPath json file
* #param width the width of the sprite, used to scale fixtures and find origin.
* #param height the height of the sprite, used to find origin.
*/
public void addFixtures(Body body, FixtureDef fixtureDef, String jsonPath, String lookupName, float width, float height) {
JsonNode collisionShapes = null;
try {
collisionShapes = json.readTree(Gdx.files.internal(jsonPath).readString());
} catch (JsonProcessingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
for (JsonNode node : collisionShapes.findPath("rigidBodies")) {
if (node.path("name").asText().equals(lookupName)) {
Array<PolygonShape> polyShapes = new Array<PolygonShape>();
Array<CircleShape> circleShapes = new Array<CircleShape>();
for (JsonNode polygon : node.findPath("polygons")) {
Array<Vector2> vertices = new Array<Vector2>(Vector2.class);
for (JsonNode vector : polygon) {
vertices.add(new Vector2(
(float)vector.path("x").asDouble() * width,
(float)vector.path("y").asDouble() * width)
.sub(width/2, height/2));
}
polyShapes.add(new PolygonShape());
polyShapes.peek().set(vertices.toArray());
}
for (final JsonNode circle : node.findPath("circles")) {
circleShapes.add(new CircleShape());
circleShapes.peek().setPosition(new Vector2(
(float)circle.path("cx").asDouble() * width,
(float)circle.path("cy").asDouble() * width)
.sub(width/2, height/2));
circleShapes.peek().setRadius((float)circle.path("r").asDouble() * width);
}
for (PolygonShape shape : polyShapes) {
Vector2 vectors[] = new Vector2[shape.getVertexCount()];
for (int i = 0; i < shape.getVertexCount(); i++) {
vectors[i] = new Vector2();
shape.getVertex(i, vectors[i]);
}
shape.set(vectors);
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
}
for (CircleShape shape : circleShapes) {
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
}
}
}
}
And I would call it like this:
physics.addFixtures(body, fixtureDef, "ship/collision_shapes.json", shipType, width, height);
Then for collision detection:
public ContactListener shipsExplode() {
ContactListener listener = new ContactListener() {
#Override
public void beginContact(Contact contact) {
Body bodyA = contact.getFixtureA().getBody();
Body bodyB = contact.getFixtureB().getBody();
for (Ship ship : ships) {
if (ship.body == bodyA) {
ship.setExplode();
}
if (ship.body == bodyB) {
ship.setExplode();
}
}
}
};
return listener;
}
then you would add the listener to the world:
world.setContactListener(physics.shipsExplode());
my sprites' width and height were small since you're dealing in meters not pixels once you start using box2d. One sprite height was 0.8f and width was 1.2f for example. If you made the sprites width and height in pixels the physics engine hits speed limits that are built in http://www.iforce2d.net/b2dtut/gotchas
Don't know if this still matter to you guys, but I built a small python script that returns the pixels positions of the points in the edges of the image. There is room to improve the script, but for me, for now its ok...
from PIL import Image, ImageFilter
filename = "dship1"
image = Image.open(filename + ".png")
image = image.filter(ImageFilter.FIND_EDGES)
image.save(filename + "_edge.png")
cols = image.width
rows = image.height
points = []
w = 1
h = 1
i = 0
for pixel in list(image.getdata()):
if pixel[3] > 0:
points.append((w, h))
if i == cols:
w = 0
i = 0
h += 1
w += 1
i += 1
with open(filename + "_points.txt", "wb") as nf:
nf.write(',\n'.join('%s, %s' % x for x in points))
In case of updates you can find them here: export positions
I'm working with CreateJS and wondered if anyone here has examples of controlling tweens using the Ticker object. I'm trying to get a sprite to follow a path defined by waypoints but i don't want to control each tween (in between waypoints) by time. I want to have smooth movement between each waypoint controlled by the Ticker object. I tried this code which doesn't seem to work at all.
var index = 0;
function move(){
index++;
if (index < path.length) {
createjs.Tween.get(person)
.to({x:gridSize * path[index][0] - pathOffset,y:gridSize * path[index][1] - pathOffset})
.call(move);
}
}
move();
createjs.Ticker.setFPS(30);
createjs.Ticker.addEventListener("tick", function(event){
createjs.Tween.tick(1);
stage.update();
});
This code seems to only jump between waypoints and not tween at all. Any ideas what i may be doing wrong or any code/tutorials which might help?
You need to add a duration(in milliseconds) to your tween, otherwise it would default to 0, this will cause the "jump", e.g.: 500 for half a second
instead of: .to({x:..., y:...})
use: .to({x:..., y:...},500)
And a second thing: You don't NEED to call createjs.Tween.tick(1); this is usually called automatically by the Tween-class.
Here is some help and some small examples: http://www.createjs.com/Docs/TweenJS/classes/Tween.html
Advanced Examples:
https://github.com/CreateJS/TweenJS/tree/master/examples
G'day all,
In short, I'm using a for loop to create a bunch of identical sprites that I want to bounce around the screen. The problem is how do I write a collision detection process for the sprites. I have used the process of placing rectangles around sprites and using the .intersects method for rectangles but in that case I created each sprite separately and could identify each one uniquely. Now I have a bunch of sprites but no apparent way to pick one from another.
In detail, if I create an object called Bouncer.cs and give it the movement instructions in it's update() method then create a bunch of sprites using this in Game.cs:
for (int i = 1; i < 5; ++i)
{
Vector2 position = new Vector2(i * 50, i * 50);
Vector2 direction = new Vector2(i * 10, i * 10);
Vector2 velocity = new Vector2(10);
Components.Add(new Bouncer(this, position, direction, velocity, i));
}
base.Initialize();
I can draw a rectangle around each one using:
foreach (Bouncer component1 in Components)
{
Bouncer thing = (Bouncer)component1;
Rectangle thingRectangle;
thingRectangle = new Rectangle((int)thing.position.X, (int)thing.position.Y, thing.sprite.Width, thing.sprite.Height);
But now, how do I check for a collision? I can hardly use:
if (thingRectangle.Intersects(thingRectangle))
I should point out I'm a teacher by trade and play with coding to keep my brain from turning to mush. Recently I have been working with Python and with Python I could just put all the sprites into a list:
sprites[];
Then I could simply refer to each as sprite[1] or sprite[2] or whatever its index in the list is. Does XNA have something like this?
Please let me know if any more code needs to be posted.
Thanks,
Andrew.
One solution, which I use in my game engine, is to have a Logic code run inside the objects for every game Update, ie. every frame. It seems you already do this, according to the variable names, which indicate you run some physics code in the objects to update their positions.
You might also want to create the collision rectangle inside the Bouncer's constructor so it's more accessible and you make good use of object oriented programming, maybe even make it an accessor, so you can make it update every time you call it instead of manually updating the bounding/collision box. For example:
public Rectangle #BoundingBox {
get { return new Rectangle(_Position.X, _Position.Y, width, height); }
}
Whichever way works, but the collision checks can be run inside the Bouncer object. You can either make the reference list of the Bouncer objects static or pass it to the objects itself. The code for collisions is very simply:
foreach(Bouncer bouncer in Components) //Components can be a static List or you can pass it on in the constructor of the Bouncer object
{
if (bouncer.BoundingBox.Intersects(this.BoundingBox))
{
//they collided
}
}