I'm trying to create a multi-level dungeon adventure in Flash CS4. The layout is an instance created of a symbol called Level, within the symbol are multiple wall subsymbols (wall), instances of Wall. There is a collision routine to stop the player walking through the walls, called from Wall.As.
Level is drawn about the centre point (0,0).
When I create an instance on the stage of Level (level), the collision tester is using the xy coordinates for the walls drawn about 0,0, not the "real" xy where it's appearing on the stage.
So what I need to know, is how to "update" the xy for each wall subsymbol with the live stage information, overriding the XYs drawn in the parent. It has to be updated unfortunately (I can't keep it static), as the levels are big so have to scroll.
Thanks for your advice.
With all due respect forget your approach, you're reinventing the wheel for nothing and probably to end up getting worse performance. What you need is pixel-perfect collision detection and probably including basic physics so already we're talking a huge amount of work. If you want to build levels in a design way for a game, use this, it'll blow your mind how awesome/easy/cool this is:
http://www.gotoandlearn.com/play.php?id=135
Its always a guess when trying to answer questions like this, as there are a lot of unknowns. That being said, in programming, there are always more than a few ways to solve a problem. Examine your collision detection routine - if you worked with hitTestPoint, and the point that was being tested (mouseX,Y or your main actor) with localToGlobal, you likely wouldn't need to test for the x,y variables of your collision objects. Read up on those two subjects and this question might be rendered moot.
At any rate, you could update relative coordinates in your Wall.as instance by leveraging globlaToLocal:
public function get curLoc():Point
{
return globalToLocal(new Point(this.x, this.y));
}
and retrieve them from your parent class as a point you can then test against:
trace(_wall.curLoc);
Hope that helps
I suppose you could accomplish what you're trying to do by manipulating the transform property of the wall symbols, but honestly I would concur with Ascension Systems and just abandon your collision testing routine for something different.
You may not need to go all out with a physics engine for your game, in which case just use hitTestObject to do the collision detection.
Related
Since I don't know english very well, I'm not able to find clear examples and/or tutorials for what I'm trying to do.
So the (maybe stupid) question is:
How can I strongly customize tweens using Starling framework and make my Sprites(or MovieClips) following a line, curve or create every other non-linear movement that doesn't exist in Transition Class?
I have no problem with Basic Starling animation. So it should be a good start point.
Thanks in advance for examples, resources or suggestions.
PS. I already visit the "Starling Wiki" page about custom Transitions but, as a Beginner(almost Intermediate) coder I wasn't able to completely understand it.
I know there are many online resources about AS3/Starling/Flash/Nape/Box2D but it's not easy for a non-english Beginner programmer to understand them.
You can simple move Starling's movieClip by set .x .y .rotation
Since now, I haven't heard of scripted transition to make predefined non linear movement. As you said, you can move object from one position to another, but it won't happen in a curved line.
What I've done in the past is to predefine the path of the movement, as I needed exactly the same weird path. I did a path tween in Flash, then used one simple function to loop through all frames (using gotoAndStop()) and getting x and y property of the object, storing them in an array. This was done when initializing. Later on I could start animation on all my weird paths whenever I wanted, using onUpdate method of tween, and passing positions from the array I've populated in the beginning.
This of course is good if you have very weird paths. If you want very little curves, you could try to do a mathematical equation. Tween classes have an update function, which will be called on each frame. So on each frame you could do some calculations and modify the parameters. For example if you tween x and y properties, you could use the update function to add a random number to those values. Of course this will make very uncontrolled movement, I'm just giving an example.
The best solution I could think of, speaking of complexity/result ratio - to use Greensock's TweenMax (look at the second example) - it has a built in bezier tweening. This means it could move from point A to point B within a bezier curve. I think this will be a good solution for your problem :)
I have a problem with a game that I'm doing. I basically have objects that are in a map and I have to check for each of them if they collide with the walls (and then do something). Since was working with AS2, I thought about doing the same way: I drew a picture with only the walls, so with only rectangles and everything else in between is transparent (does not exist, then the floor for example). In AS2 I put the image to the screen, let's call it wall, and then I did a hitTest to wall with every object. That is for instance, the object was actually on the image, since that the transparent parts were part of it, but the function was testing only on the visible parts, and so with the walls. So it worked.
Now in AS3 there is no HitTest but hitTestObject, which I used, and I do for example wall.hitTestObject(object). The problem is that this function is as if it doens't see the transparencies, and the objects while not touching the walls collide with them!
I found the PixelPerfectCollisionDetection that actually solves the problem but it is huge and heavy so in my case, with so many objects to be tested (at least 60) at each frame, the game slows down a lot!
What I need is a function like hitTestObject (i don't need a lot of accuracy!) that take care of the transparent parts of an image.
How can I do?
As mentioned in the comments, physics/game libraries will have this code built-in for you and should work out of the box.
But if you want to build it yourself, or even introduce your own optimizations, the first step (which is very inexpensive) is checking for bounds collision using entirely built-in functionality of DisplayObject.getBounds and Rectangle.intersects (though you must do so in a consistent coordinate space, i.e. the stage):
if (obj1.getBounds(stage).intersects(obj2.getBounds(stage)) {
// Cheap bounds intersection is true, now do pixel-perfect detection...
}
Then if the bounds check is true, perform the pixel-perfect collision detection.
It seems that BitmapData.hitTest is your best bet - see a blog post by Mike Chambers.
Prior to this method, if you're interested in neat techniques, there was a method outlined by Grant Skinner in his blog. It's quite a clever algorithm using built-in bitmap routines (aka, fairly fast), creating a BitmapData only as large as the overlapping region (or even scaling that down), and drawing the two objects into specific channels of the bitmapdata, then using BitmapData.getColorBoundsRect() to determine if there are any pixels touch. I'm guessing BitmapData.hitTest is faster, but it'd be fun to compare.
I ran into the same problem and to be honest i found the easy way to get rid of that is just generating a "mask" layer for the collisions. You can always place this under your background so it doesn't show, or change the transparencies and whatsoever. Do this in Flash, and after "covering" with rectangles (or whatever) the collisions, just select them all and make that a movie clip.
I'm guessing since you made the symbol in Flash, it obviously knows that even if the symbol consists of several individual drawings or whatever, it's not just an image.
For me this worked fine .
I'm totally beginner in Flash and Actionscript so sorry if my questuon is stupid.
I have to make a platform game - I'm planning to write something like Icy Tower - my character is jumping from one platform to another to get to the top of a tower of something. And here is my problem - I want to allow the character to jump onto a platform only from the top, but if he collides with whe platform from the bottom, or from the side, I want him to bounce (I hope you understand what I want mean).
So, to do something like that, I need to be able to detect where exactly do these two objects collide - the only solutions that comes to my mind is to keep the coordinates of every platform in some array and compare them with the characeter's position evertime he jumps, but it just doesn't seem right. Is there an better way to solve this problem?
I will be grateful for any advice.
PS. Sorry for my English
You can make use of a game library like flixel, or flashpunk. They are both great.
Essentially, you will need to iterate over all objects that your character can collide with. You can make use of .hitTestObject() to roughly determine if your character is colliding with any of the objects. Thereafter you can then get the coordinates and dimensions of your character on the stage and compare them to the coordinates and dimensions of the hit object to determine directions.
So in psuedo code
for each (var platform:DisplayObject in platforms) {
if (character.hitTestObject(platform)) {
if (collideFromBottom || collideFromSide) {
// allow movement
}
if (collideFromTop) {
// stop downward velocity
}
break; // might as well, as you have detected the collision
}
}
CollideFromBottom would be comparing the top of your character with the bottom of the platform. Remember that as Sprites, both player and platform have [x,y] properties and [width,height], allowing you to determine coordinates.
P.S. this question should have been asked at gamedev.stackexchange.com
I'd recommend you to use a Physics Engine like Box2D(
behold the examples), instead of creating some hitTest colision based game from scratch.
The probability of you having serious code/design problems and leaving the project aside are big.
There's a lot of good tutorials on internet, here a good resource - Using Box2d to Create a Side Scrolling Game:
Part 1
Part 2
I'm brand new to Flash (and game programming, really), but want to learn a bit of it. My overall learning project is to create a Monopoly clone in Flash. Unfortunately, I'm struggling to get over even my first hurdle - how to create the board graphically, and how then to deal with it in the code. So far, my thoughts are to break the board down into the different sizes of tiles (the normal property ones, the corner 4 and a large one for the middle section), then somehow place these all in the correct position relative to each other and keep that positioning correct as the pieces (and thus the camera view) move about the board. (And, hopefully some day have a zooming ability too...)
Is this a good approach, or is there a better one? Does anyone know where I can find a tutorial specifically on creating board games in Flash (any sort really, wouldn't have to be Monopoly but just a game that has a board which tokens move across - and preferably which has to pan as well).
Also, as an aside, is there any way to have a dynamically coloured rectangle in a flash MovieClip (like you can have dynamic textboxs)? I ask because it would be useful if there was, as I could generate every property tile with just one MovieClip which took a name, a value and a colour...
everything you describe here you can do pretty easily once you get the hang of component sprites. personally i would make a single sprite that will then hold all of the "tiles" in the game, this would allow you to "zoom" the board while keeping all the pieces relative:
if you create this parent to have an addTile() and getTile(index:int):Sprite method then you can easily push the tiles and retrieve them from an array, so that Go is at index 0, old kent road is at 1 etc. that way you can use a single integer value to determine the position of the player piece as you can then use getTile(int).x etc.
the position of the tiles themselves can be worked out relative to the others. if you have a tile that is 20px wide and 40px high then you can position the tile as x = index * 20 for the first row, after the initial 11, you need to rotate them all and then use the y index instead (rotation = 90; x = 11*20; y = (index-11)*20) this will depend exactly on your origin point of your Sprite.
to draw coloured boxes you use the graphics of the Sprite, there are plenty of tuts on API drawing out there, but here is a basic box of 10x10px:
var drawing:Sprite = new Sprite();
drawing.graphics.beginFill(0x0000FF);
drawing.graphics.drawRect(0, 0, 10, 10);
drawing.graphics.endFill();
Another approach to your question could be to learn about Object Oriented Programming. That may not solve your representing the board graphically straight away, but it would definitely help you structure your game.
With OOP, you could define a "Property" Class with a set of properties such as streetName , color , price etc... I haven't played Monopoly in a while but you can get the general idea, i.e. to create a base object and make it specific by setting the object's properties. Your question about the colored rectangle can actually apply to other properties, a great way to avoid unnecessary repetition.
Broadly speaking OOP tends to emulate real life situations, so you could actually look at your Monopoly game, break it into its various parts, find common properties etc... I won't start a lesson here :) I'd be pretty bad at it, but there's plenty of resources out there . Look for OOP, Design Patterns & Actionscript3.
After a little research, you may find that your question about how to handle graphics may not be such a problem after all.
Your questions are way too general. I'm sure you don't want us to walk you through your whole project right?
Now to gain some experience, I suggest to you simply work through a few flash gaming tutorials. There are a LOT of those, I googled for 2-3 seconds and found this:
http://pelfusion.com/tutorials/35-flash-game-development-tutorials-fla-files/
I'm sure you feel disappointed by this answer, but this is the first step in solving your own problems. The internet has more than enough general game tutorials already. If you have specific problems, we might be of better help to you.
I assume with dynamically colored rectangles, you mean simply changing the color during runtime. Well you simply give the rectangle a name, and change the color property of it in code. Like this: rectangle.Color = Something.
You might want to start out with a simpler project just to learn some of the basics, maybe a little game where the player has to move a rectangle from one side of the screen to the other using the arrow keys or mouse, upon which a score is incremented or something. This will help teach you how the coordinate system works, among other things.
To draw stuff using code, you can create a new Sprite or MovieClip object and use its graphics property to draw primitive shapes (rectangles, etc.) to it at runtime.
Currently I'm writing an app. If I want to avoid Singletons, do I have to simply pass references of everything around?
For example,
I have a "main" class.
Class: Main
+---- Screen
+---- Camera
+---- Terrain
+---- Vehicle
+---- PhysicsWorld
It contains my Camera, Terrain, and Vehicle,etc classes. Now, I have issues when I'm creating say, the Terrain object. Terrain wants to access Main classes Screen object so it can add its Terrain Graphics to the screen. It also wants to know about the Camera object for when it is drawing so it knows what scale to draw it. It also wants to know about my PhysicsWorld object so it can add itself to the physics engine.
Do I have to always lug these objects back and forth between constructors? I mean, when I create a Terrain object, do I simply have to pass around my screen object, my physicsWorld, camera, etc?
Another random scenario I have, is now.. inside my Vehicle class I need to call a Restart() method on my Main class. Does this mean I have to pass an instance of main to Vehicle? Really??
It feels cumbersome to constantly have to pass 4-5 things to my classes, especially in my scenario now where almost every in-game object I have needs a screen, physics, camera info, etc.
Any suggestions?
It feels cumbersome to constantly have
to pass 4-5 things to my classes,
especially in my scenario now where
almost every in-game object I have
needs a screen, physics, camera info,
etc.
Then the correct question to ask is "why do I need all 5 objects in all my classes?"
Why on Earth does every in-gmae object need any of the mentioned things? An in-game object needs a position and whatever it needs to process its behavior. Then a separate renderer can, you know, render, the object. Which means that only the renderer needs the camera info and screen.
The physics could go either way. You could have a separate physics entity which updates the game object, or you could pass that physics object to every game object. But even if you do pass that around, we're down to one out of the three objects listed. :)
That's why globals and singletons are often best avoided. They disguise your dependencies so you end up with far more dependencies between your objects than you actually need. And then it becomes almost impossible to remove the globals.
However, if you do stick with globals, do yourself a favor, and at least avoid singletons. You don't need the additional constraints enforced by a singleton.
Terrain wants to access Main classes
Screen object so it can add its
Terrain Graphics to the screen. It
also wants to know about the Camera
object for when it is drawing so it
knows what scale to draw it. It also
wants to know about my PhysicsWorld
object so it can add itself to the
physics engine.
The terrain object needs to know one thing: What is the terrain like. Someone else can take responsibility for rendering it. That someone will need to know about the camera, screen and terrain graphics, sure, which suggests that the same object might plausibly be able to do other tasks involving these objects (such as other rendering tasks).
Why should the terrain care about what scale it's drawn in? It needs to know the scale ingame, but not the scale in camera-space. And why can't someone else add the terrain to the physics engine? The main function might be able to do that, even. Create terrain, create physics engine, register terrain with physics engine, start game.
I don't know ActionScript, but assuming variables are passed by reference, the least you could do is construct a 'Environment' class holding Camera, Screen, Terrain, PhysicsWorld which you pass to the instances.
I have the exact same problem (also in actionscript 3, coincidentally).
I have been working on an RTS for flash and had found myself needing to pass around large numbers of references to each new class (e.g., gameGrid, currentSelection, visibleUnits, etc.).
I eventually realised that what I really should be doing is to have every class maintain it's own properties, and instead pass around references to these classes, (well objects).
But anyway, now what I'm doing is having static variables containing references to commonly used objects such as the main stage, interface, engine and display area inside a class called RTSGlobals. I'm also putting constants such as the screen size in there.
I know this doesn't really answer your question, but I figure sometimes it is worth ignoring a bit of OOP good practice in favour of an efficient solution.
If someone has a does have a good practice solution though, please tell :)
I suggest you take a look at XNA's samples projects (google it). They're well designed and might give you some hints.
Also, since you're using AS3, you could use the event system to dispatch message to other entities. For example, instead of passing your Main to your Vehicle class, make your Main (or whatever else interested) a listener of your Vehicle class. Then, let's say the car crash and you want to restart the game, dispatch an event, for example CAR_CRASHED. The listeners of your car should do something based on this message. If you want to understand the event system, type EventDispatcher, highlight it and hit F1 in your Flash IDE.