I want to do the following:
which is
apply the rotation
and then, resize the Sprite
But since Sprite transformations have a predefined order, this is what happens:
resize the Sprite
rotate it
So, my question is, is there any way to do it?
If you take a look at the API docs, it says...
Sets the size of the sprite when drawn, before scaling and rotation are applied.
So I guess the only way to do it is modifying manually the vertices? Or am I wrong? Any better way?
Related
In LibGDX, I'm trying to create a game where you play a character who must survive waves of zombies. The plan is, when a zombie touches the player, the player loses health, and the zombie despawns; this works well until any of the sprites are rotated. Here's a screenshot of what I can imagine to be why:
To check the collisions, I use:
if (sprite.getBoundingRectangle().overlaps(Game.pl1.sprite.getBoundingRectangle())) {}
.. this is inside the Zombie class, and Game.pl1.sprite refers to the sprite belonging to the player.
So the red box is where I'm assuming the bounding rectangle is, based on where zombies despawn around it.
This is what I want the bounding rectangle to be:
I'm not sure if I can achieve this just using sprite.getBoundingRectangle so I was thinking perhaps I would need to use Box2D or maybe convert the sprite to a texture.
You could get the dimensions for a rectangle the size of the sprite if it wasn't rotated, and then rotate that.
I've seen in flash sidescrollers they mostly use sidescroller by making the background move.
But if I had a background and I wanted the player to move and the camera to follow, how would I do it?
There are several ways to accomplish this. The first is to put all of the background objects into a container MovieClip and move that instead of the player. This also makes other aspects of having a camera, such as zoom and rotation, relatively simple, since you can just scale and rotate the container MovieClip.
Another method is putting all background objects into an array. Every time there is movement, you loop through the array and move the objects. This requires more math and separate x/ y variables for each object, so it's not as convenient.
One thing to note is that if you're going to rotate the camera, you might experience vibration issues as your camera gets further away from the origin. To prevent this, you'll have to shift all of the objects in your container MovieClip closer to the origin when they get too far away.
If you want the camera to ease towards the player's position, you just move 1/10 (or some other fraction) of the distance to the camera's target position each frame.
I am slightly confused about the "correct" way in KineticJS to fill a shape with partial images (crops) from a combined image file (sprite).
Seems like one can either use fillPatternImage with a defined offset, which seems to draw the complete image, albeit with the rest of the image invisible. I only got acceptable performance after I moved those shapes to an extra layer as my sprite is relatively large and the impact of not cropping correctly decreased the fps dramatically.
All alternatives that I have found use the attribute "fill" with another attribute "image" in it, but this seems to result in black background every time.
Using an Image-shape would help, but is rarely usable since my shapes are seldom rectangular.
Since the KineticJS-documentation does not mention specifying crop coordinates ("just" offset, w/o width and height), what is the absolute correct way to do it?
The absolute "absolute correct way" would depend on the platform and your particular code, but.
Have you looked at sprites? http://www.html5canvastutorials.com/kineticjs/html5-canvas-kineticjs-sprite-tutorial/.
To mask simple animated sprites I'd use this in adition of plain javascript after each draw.
context.globalCompositeOperation = 'destination-in';
The performance of drawImage with composite operations is better than drawing shapes manually on webkit, at least.
I wrote a paint application using the HTML5 canvas element.
Now I want to give the user an option to zoom in and out while painting.
How can I do this?
There are a few ways. It really depends on what you're looking for.
You could do it by scaling the entire context, as in ctx.scale(2,2), and then redrawing everything at this larger scale. Several things drawn, like paths and text, will scale gracefully. To accomplish this you will need to keep good track of everything drawn so far.
Another way is to take the entire canvas and draw it back to itself. This requires a temporary canvas because the operation is really: Draw to temp canvas, clear main, draw back to main scaled.
Another way is to use CSS transforms to merely zoom the canvas itself, which will make the image blurry (its zoomed!) but does not require changing any of the pixels already on the canvas.
So created a Sprite to which I add other Sprites which are game tiles. Each tile is 60 x 60 px big. In result I've the Sprite with about 200 childs (those tiles).
When I try to startDrag() the container sprite the lag when moving it is very noticeable..
Is there a way like to join the tile Sprites so the container would have only 1 child Sprite instead of 200? Because it lags so much probably cause it needs to move (change the x and y) all those 200 tiles.. Am I correct?
In this case I can't use the cacheAsBitmap property, cause user can zoom in or zoom out the map..
Glycerine & Aurel do touch the crux of the real solutions. However I'd like to add.
You are correct by the way, when you said it has to manage so many sprite locations when you move the container around. CacheAsBitmap sure does does tackle this to great extent but the real solution is blitting. Try this link for that :
http://www.adobe.com/devnet/flash/articles/blitting_mc.html
It doesn't matter if a user zoom or something of that sort is required cause you can always switch between bitmap data & the original vector sprites. Your problem arises in moving.managing lotsa sprites, so just before doing that use optimizations, after that let them be back to their selves.
I've had the same issue before. Is it possible to 'join' them together - in a sense.
When you add your 200 sprites onto a screen - I assume you put them all into another parent sprite.
A this point - you will take a snapshot, or a screenshot - or a photographic replica (whatever you want to call it) of all the sprites and write the image (bitmapData) to a parent sprite. At this point. delete/remove/hide/nullify the original sprites and you'll be left with a sprite containing bitmap data.
One big image to move about and zooming and the like is no bother.
If you need code - ask. It's time consuming code so you tell me first then I'll write it :P
Hm, joining them would actually be quite hard... You would need to get the graphics, the code and all and put that into the parent...
I don't think that is the problem - you should do something else... In this case, I think that by "tiles" you mean that the parent would be a tile map, correct? So, you probably have a 2-dimensional array (array of arrays) with tile types - instead of parsing that array at initialization, creating A LOT of Sprites, try re-parsing it in each frame (it is faster), but add only the Sprites that are possible to see. That is - their X position (after adding the zoom and camera X) is greater than -sprite.width, where the height is also scaled by the zoom, and lesser than stage.width + sprite.width (again, width after zoom). Same goes for Y, only with the height attributes.