Both of the methods look similar, but I'm having a hard time understanding when to use these. I just want to know where to use these two, e.g. sprite.draw(batch) and batch.draw(sprite,x,y).
One is for drawing a texture the other is for drawing a sprite.
spriteBatch.begin();
spriteBach.draw(texture, x,y);
spriteBatch.end();
and
spriteBatch.begin();
sprite.draw(sprite,x,y);
spriteBatch.end();
Link to relevant libgdx wiki: Spritebatch, Textureregions, and Sprites
Related
In my first LibGdx Project,I want to draw some rectangles.
I am not looking for shape rendering purpose.I am aiming to implement a function like what fillRect() in j2me do.I have to draw filled rectangles and need to manipulate it(changing size,rotating.. etc).
When I google about it, always getting shapeRenderer related things only.
Please mention how can I draw and manipulate my own images.
Draw Rectangle by using Pixmap.
Texture texture=getPixmapTexture(Color.WHITE);
Sprite sprite=new Sprite(texture); //Used for drawing 2D sprites.
//or
Image image=new Image(texture); //2D scene graph node.
public static Texture getPixmapTexture(Color color){
return new Texture(PixmapBuilder.getPixmapRectangle(1, 1, color));
}
public static Pixmap getPixmapRectangle(int width, int height, Color color){
Pixmap pixmap=new Pixmap(width, height, Pixmap.Format.RGBA8888);
pixmap.setColor(color);
pixmap.fillRectangle(0,0, pixmap.getWidth(), pixmap.getHeight());
return pixmap;
}
The answer by Abhishek is correct.
However, if you have just started game developement with LibGDX, I would check whether you need at all to perform such operation (draw a rectangle).
In libGDX you can use Scene2D which allow you to create a Stage, Actors and direct them on your stage.
So instead of drawing a rectangle, you create an actor, such as an image, to which you can associate a texture, a button or a TextBox and place it on your screen.
Scene2D allows you to then use things like Action or rotation, scaling..
There are some good visual demos about that on Libgdx.info
I am mentioning this because moving to Scene2D later may be more complicated than if you make that decision early on.
I'm just getting started with Flash/ActionScript and it seems to be the general consensus to create Sprites, Bitmaps, MovieClips, etc for various objects in order to represent pictures and other graphics.
However, the way I'm used to writing games and whatnot in other languages is to just loop repeatedly and each frame use something similar to the Graphics object to redraw the scene on the main Sprite. Is this how it's also done in Flash, and is it good practice? I can do it this way, but I'm wondering if there's some Flash ecosystem standard instead.
Here's an example of the way I'm used to:
public class MyApp extends Sprite
{
public function MyApp()
{
var t:Timer = new Timer(20);
t.addEventListener(TimerEvent.TIMER, update);
t.start();
}
public function update(e:TimerEvent)
{
this.graphics.clear();
//Rendering code and updating of objects.
}
}
Is this acceptable?
Well, it depends.
In Flash, you have the option of relying on the Flash Player's vector rasterizer and rendering system, which will figure out all the redrawing for you. For instance, you can draw once to a Sprite then simply apply transforms to the sprite (set x, y, width, height, rotation, scaleX, scaleY, transform.matrix, transform.colorTransform, etc). Any of these objects could be a vector shape or a bitmap, and you can also use cacheAsBitmap and cacheAsBitmapMatrix for even more redraw optimization. The Flash Player will only redraw areas that change, on the frame that they change. I would consider this the traditional "Flash way".
Using the Graphics API is just a programmatic way to create vector shape data. Think of it as a code alternative to drawing in the Flash IDE. You could draw using Graphics once when the object is created, or if you needed to change the actual shape (ie not just the transform) you are correct that you would clear() and redraw it. However, ideally you would not be doing that a lot. If you find yourself redrawing the shape a lot, you might want to move to a pre-rendered sprite-sheet approach. In that case you use BitmapData to more quickly copy pre-drawn pixel data to a Bitmap object. This is generally faster than relying on the vector rasterizer to render your Graphics commands, as long as you use the fast pixel methods like copyPixels(). This is probably closer to the sort of rendering systems you are used to in other platforms that don't have a vector rasterizer built in.
Lastly, it's worth noting that the newest (and fastest) way to render objects in Flash is completely different than all that. It's called Stage3D and it uses a completely different rendering pipeline than the vector rasterizer. It's powered by GPU rendering APIs, so it's blazing fast (great for games) but has no vector rasterizing abilities. It can be used for both 3D and 2D. It's a bit more involved to work with, but there are some useful frameworks to make it easier, most notably the Starling 2D framework.
Hope that helps.
The "Flash way" is to use EnterFrame event instead of using timer to draw. You must make your calculation whenever you want but let flash draw you scene.
It works the same way in actionscript.
public class App extends Sprite // adding "my" to identifier names doesn't add any information, so there's no real point in doing it
{
public function App()
{
addEventListener(Event.ENTER_FRAME, update); // "each frame"
}
private function update(e:Event):void //not just parameters of functions have a type, but also their return value
{
graphics.clear(); // no need for "this" here
//Rendering code and updating of objects.
}
}
Keep in mind that the Graphics API is vector based and as such will only draw so many things before dropping performance.
Sprite is a general purpose container, not to be confused with what the term "sprite" stands for in a sprite sheet.
What you are probably referring to when saying "main Sprite" is some rectangular region of pixels that you can manipulate.In this case, a BitmapData is what you want, which is displayed with a Bitmap object.
BitmapData does not offer a graphics property. Essentially, drawing vectors and manipulating pixels are treated separately in As3. If you want to draw a line in a BitmapData object, you'd have to first draw the line as a vector into a Sprite (or better Shape, if all you want to do is draw on it) using its graphics property, then use draw() of BitmapData to set its pixels according to the drawn line.
I have a question about stages and actors in libgdx. I'd like to delegate the draw function to stage, in order to use actions, but I need to customize these actors. Are there any way to extend an actor, assign him an Image or Texture, and not implement the draw method? Is mandatory implement the draw method or is there a way to delegate this to the stage?
Thanks you!
I think your are looking for Image. Image is a subclass of Actor which allready implements a draw-method itself. You can simply give its constructor a Drawable and it will draw it at the right position with the right size, scale, rotation...
So what you want is to extend Image.
The stage is not responsible for the drawing, it is just the "manager", which tells the Actors to update and draw themself. As much as i know it actually calls draw only for those Actors, which are inside the camera, as others are not visible and so they don't have to be drawn.
I am using GL 2.0 (in order to display pictures that are not power of 2), and I am trying to simply render a mesh (that displays some triangles).
When using GL 1.0, I didn't have any problem, but now, I have to pass a ShaderProgram object as a parameter.
How can I make it work like it would in GL 1.0?
Should I make a shader that simply does nothing?
You have to use a vertex shader to convert world space coordinates into screen space coordinates. And you need a pixel shader to look up texture coordinates for each rendered pixel of your quad.
Look at the shaders that Libgdx uses for its SpriteBatch, they are pretty minimal texture-a-quad shaders. You can literally use SpriteBatch.createDefaultShader() to get them or just use them as inspiration for your own shaders.
The libgdx wiki page on shaders already contains an example code for a simple shader:
https://github.com/libgdx/libgdx/wiki/Shaders
I assume it's basically the same as the createDefaultShader() as in P.T.'s answer...
Hope it helps...
I'm new to AS3 and I'm trying to create a simple game with it.
So far, I have been able to draw images like this:
[Embed(source = 'C:/mypath/myimage.png')]
public static var myImageClass:Class;
private var myImage:Bitmap = new myImageClass();
and then render myImage.
but that draws only a picture with no animation.
What I want is to import this picture:
and then cut the image to series of subimages and draw an animation out of them, rather than a single image. How may I do this?
Thanks!
This is called "Blitting". You could accomplish it with fairly decent results, depending on your deployment target and how many animations you require, using BitmapData.copyPixels(), but it's more ideal to use the Starling Framework, which employs Stage3D hardware acceleration.
More here:
Introducing the Starling Framework (Video tutorial)
Starling documentation
What you are looking for is SpriteSheet support. You can easily write this yourself or use existing libraries (like Starling for instance).
The idea is to draw an area of the image at each frame to actually create the animation. Depending on the format of your sprite sheet, you may have to add another file to describe the positions of each rectangle to draw.
This page explains how to implement it.