AS3 Defining coords for a screenshot? - actionscript-3

I've built a photo booth app for an installation and I need to take a screen shot of the bitmap data with it's frame... I foolishly nested my objects all wrong way too early in the game so taking a picture of just the display object is moot at this juncture, and I dont have time to re-organize everything.
I know the encoder can output stills of the stage, but can that be a defined set of coords? I have an 800x600 region that needs to output, ignoring the rest of the stage.
I am playing with other options as well, but if there is anything that seems obvious, i would greatly appreaciate it!

You can get the whole stage as a bitmap data and then use the copypixels method to copy the region you need.
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/BitmapData.html#copyPixels%28%29
Or you can use the draw method of BitmapData class to draw a display object into that bitmap data.
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/BitmapData.html#draw%28%29

Related

How to use cache on Movieclip with createJS and Flash CC

Hi all I want to ask something. I've made a game with Flash CC and createJS. it's a Drag and drop game (3 object for drag, and 3 object for drop) and a lot of vector movieclip object. But when I run it in mobile, the game looks like have a performance issues. I've read some article that talk about caching the object. But I'm really dont know anything about cache and don't know how to use it on an object like movieclip. Do you have any explanation or solution or maybe a tutorial how to use cache function? Thank you very much.
From the docs:
Draws the display object into a new canvas, which is then used for subsequent draws. For complex content that does not change frequently (ex. a Container with many children that do not move, or a complex vector Shape), this can provide for much faster rendering because the content does not need to be re-rendered each tick. The cached display object can be moved, rotated, faded, etc freely, however if its content changes, you must manually update the cache by calling updateCache() or cache() again. You must specify the cache area via the x, y, w, and h parameters. This defines the rectangle that will be rendered and cached using this display object's coordinates.
http://createjs.com/Docs/EaselJS/classes/DisplayObject.html#method_cache
So, you don't want to cache a playing MovieClip (you would have to update the cache every frame, which is slow). However, you could cache elements in the MC that are just being transformed.
For example, an animation of a walking character, with complex vector shapes for the arms, legs, head, and body that are being transformed (scaled, rotated, translated) to create the walk animation. You wouldn't cache the character MC, but you could cache the body parts themselves.

How do i create an animation in AS3?

I am making a game in AS3 for a school project (using the AIR api). I have about a year's worth of experience in AS3, so i would say i'm proficient but not an expert. Anyway, i have never attempted to do sprite animations in AS3 and i'm not quite sure how to approach it.
If i create a list of bitmaps and call addChild() and removeChild() to display each frame of the animation, it would affect the framerate as these functions are not very efficient (i have tried this before and it tanked my framerate if i had too many animations going at once). I have also tried creating a list of BitmapData objects, adding a bitmap to the display list, and then pointing it to a different BitmapData each frame, but this does not seem to work at all.
So what is the best way to do this? In XNA, for example, i would create a sprite class that draws to the screen using a sprite batch, then i would create a list of sprite objects and cycle through them to create the animation. Is there any way to achieve a similar result in actionscript?
First (simple) method: you can just use multi-frame MovieClip for animation. Put an image in each frame, put a MovieClip on the stage and that's all. You can control this animation using play(), stop(), gotoAndPlay(), gotoAndStop(). It will work without much problems for a generic platform game (I did that myself long ago).
Second (advanced) method: use bitmap blitting. For each animation, create a bitmap image that holds each frame of the animation. Use this image as a source for copying pixels into your current animated object. You just need to copy a particular rectangle area inside a source bitmap that corresponds to the current frame.
The actual blitting happens here
destinationBitmapData.copyPixels(sourceBitmapData, areaRectangle, destinationPoint);
Where destinationBitmapData is your "canvas" that you're blitting to; sourceBitmapData is the source image holding all animation frames; areaRectangle is the Rectangle inside the source image defining which area to copy; destinationPoint is left-top coordinate of the copy area in your canvas.
The destination canvas can be just one small object (like your game character that is moving around) or the entire game screen with all objects. I.e. instead of blitting and adding each object separately, you can just have one big canvas and blit any necessary parts directly to it.
That said, there is already a number of various ready-made engines that use blitting and even advanced techniques like 3D acceleration for 2D sprites.
One of them is Starling.

Spritesheet with mask or separate image files?

I'm making an animation of a 2D character that can walk, run, jump, bend,...
Would it be better to load one big 'spritesheet' with all the animations and just use a mask, or would loading separate files (walk, run,...) be better because you're not using a mask on such a big image every frame?
I'm not using the Stage3D features with a framework like Starling because I think the normal flash display API is fast enough and has much less bugs than the relatively new GPU frameworks.
Blitting just the character (using lock(),copyPixels(),unlock()) works pretty well.
private function updatePixels():void{
//update sprite sheet copy position based on the frame placements ons prite sheet
position.x = spriteSourceData[currentFrame].x + offset.x;
position.y = spriteSourceData[currentFrame].y + offset.y;
//draw into the bitmap displayed
displayData.lock();
displayData.fillRect(displayData.rect, 0x00FFFFFF);//clear
displayData.copyPixels(sourceData, spriteData[currentFrame], position);//copy new frame pixels
displayData.unlock();
}
//a bit about vars:
position:Point
spriteSourceData:Vector.<Rectangle> - from parsed Texture Packer data
offset:Point - front view and side view animations weren't always centred, so an offset was needed
displayData:BitmapData - pluging into a Bitmap object displayed
sourceData:BitmapData - the large sprite sheet
currentFrame:int - image index on the sprite sheet
I've done this on an older project writing a custom class loosely following what I've learned from Lee Brimelow's tutorial series Sprite Sheets and Blitting (Part 1,Part 2, Part 3)
In short, you'd use two BitmapData objects:
a large sprite sheet
a small image to display just the character (size of the largest character bounding box) to copy pixels into
In my project I had a character with front and side animations and for the sides I've used one set of animations and used the Matrix class to flip(scale and translate) the side animation accordingly. I've used TexturePacker to export the image sequence as a sprite sheet and the frame data as well as a JSON object. There is native JSON support now, so that's handy. Texture Packer isn't free but it's really worth the money (affordable, fast and does the job perfectly). I haven't used Flash CS6 yet but I imagine it's also possible to import your image sequence and export a spritesheet with the new feature.
In my experience the rule "the simpler the display list the better the performance" generally applies. Which means you should use the most specific display object that will do the job (don't use a Sprite when a Shape would be sufficient or favor Bitmaps over vectors where it makes sense).
The most extreme version of this is to only have one Bitmap display object on the stage and use copyPixels to draw all game objects into it every time you want to update the screen. It doesn't really matter what the source in the copyPixel call is, it could either be a large BitmapData acting as a sprite sheet or a small BitmapData objects representing a single frame in an animation. This method is really fast and you could easily have many hundreds of objects on screen at the same time. But using copyPixels means you can't scale or rotate a game object, so for those cases you would have to fall back to the much slower draw() method. Of course this single Bitmap method is not suitable for games where you need to attach mouse events to specfic objects in the game, but works well for shoot'em ups or platform games.
To answer your question, I think you will get better performance by using a single Bitmap display object to represent the player and a collection of BitmapData objects for all the animation frames. Then you can just change the Bitmap's bitmapData property to the frame you want to display. You can still load a large spritesheet png and then plit it up into a series of BitmapData objects during the initialization of the game.

How to extract the shape of MovieClip?

We have a flash application that we are planning on converting to javascript. It's a pretty simple map application with an image as the background and a bunch of simple polygon movie clips that represent destinations on the map.
I would like to iterate through each movie clip and extract the shape into an array of x,y points to redraw the polygon using an external javascript function.
Is this possible with actionscript?
If you want to export the shape coordinates at author time, you can do try the JSFL script recommented by #strille or this one or export transparent images (if that's not too limiting for your application).
If you need to export the shapes at runtime, you can use the awesome as3swf library to decompile the swf and export the shapes. Have a look at the ShapeExport wiki as there are couple of handy exporters for js like JSCanvasShapeExporter and the more generic JSONShapeExporter
There are ways you can read the coordinates from an SWF. For instance, I've written a parser in PHP (link). Getting the data doesn't help though, as it turns out. The Flash painting model is different enough from the HTML5 one enough to make transfer exceeding difficult. The main obstacle I discovered is that in Flash, a path can be filled with two fill styles: one for area enclosed by the path, the other for enclosed area considered to be "outside" by the even-odd rule (e.g. the pentagon in the middle of a star). Since the HTML5 canvas let you specify only one fill style, you can't redraw shapes from Flash accurately. I was trying to create a tool that extract shapes as SVG and was getting a lot of gap and holes in the result.
Flash Player 11.6 introduced readGraphicsData() which does exactly what you ask for.
If you need to target an earlier version, then there's no simple way to read shape coordinates from a display object with ActionScript at runtime unfortunately.
If you just want to extract the shape coordinates once someone has written a jsfl script for Flash CS3 which looks like it might be able to help you out.

Live Video Keying with Flash (AS3)? How to do that?

For a new project, I want to take a video feed, filmed in a greenscreen room, and as you see it, do a color keying, to kill the green and show an alternative picture on the background.
Is there a way to do this with Flash, AS3?
optional question: If a button is clicked, the now new constructed Picture should be saved as a Jpg. Any Idea?
Thanks a lot for you help!
For this sort of thing you're going to need to use Pixel Blender: http://www.adobe.com/devnet/pixelbender.html and possibly Alchemy as well http://labs.adobe.com/technologies/alchemy/
Sorry I can't give you more info than that as I've never worked with them before.
To capture a screen grab, it's easier. Create a new BitmapData object the size that you want your final image. Use the draw() method on it to capture the stage (or holding clip etc). Grab the as3corelib from here: https://github.com/mikechambers/as3corelib and use the JPGEncoder or PNGEncoder class to create a jpg or png (personally I prefer png, as even though the filesize is bigger, it's much quicker to generate as you don't need to worry about compression).
Then, use the FileReference class ( http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/FileReference.html) to save it out (JPGEncoder and PNGEncoder both return your image as a ByteArray so just pass that as the data to the FileReference.save() function).