I have a question with regards to using replace scene in cocos2d.
Assume my game menu has the following structure:
Main Menu
Play
2.1 Strategy levels
2.2 Accuracy levels
Settings
Tutorial
Is the recommended method of navigation between the menus, "replace scene" or "push/pop"?
I've read in some places that its good to avoid push/pop in cocos2d. But my concern in using replace scene is that i have the impression that im just stacking up scenes instead of having a proper navigational flow.
Push and pop scene is going to stack your scenes. Each time you push a new scene, the old scene remains in memory and you need the exact same amount of popScene to get back to the initial scene.
So yes, using replaceScene is the standard and recommended method of switching scenes. While replaceScene removes the original scene from memory, there is a short time of overlap where both scenes remain in memory. So if you have two very memory intensive scenes, it is recommended to go through a temporary loading scene instead to allow the previous scene enough time to release its memory.
Note also that you cannot call replaceScene within the init method of a scene. That will cause CCDirector to crash.
Related
Thanx in advance..I have a problem , how we release memory in cocos2dx ??
In my game, my first scene takes a lot of memory because there are so many animations run at a single time on this scene,there are so many animations , so i am satisfied with this but when we go to next scene, it does not release previous memory used,this is my problem so how we release memory used by previous scene when we change the scene?
To go between scenes you can either call pushScene or replaceScene.
Push Scene
If you're pushing between scenes then I recommend that you have a loading scene in between. It should be lightweight so that you have a chance to release everything from your old scene. This is where the onEnter(DidFinish) and onExit(DidStart) methods come in handy.
The chain of calls would be:
oldScene->onExitDidStart()
loadScene->onEnter()
oldScene->onExit() <-- this is where you release everything
loadScene->onEnterDidFinish() <-- this is where you load up the new scene
newScene->onEnter()
and so on... If you've managed your memory correctly then you shouldn't have 2 heavy scenes at once.
Replace Scene
This is a much easier scenario. You simply need to make sure that for the new scene you load as little as possible until the old scene has completely disappeared. I.e. when onEnterDidFinish() is called, or even 1 frame after it.
Cocos2d-x supports auto release memory. For example, when you create a sprite by calling Sprite::create() it will add this sprite to the auto-release pool. If you don't add this sprite to become the child (or n-th leveled child) of the current scene, it will be released.
Do not create an object using new,use create() instead when you call the next scene, everything from the last scene are released.
I have used
[[CCDirector sharedDirector] replaceScene:[CCBReader sceneWithNodeGraphFromFile:#"SongScene.ccbi"] ];
For load the next scene. It take a little delay to load the scene. When the second time loading, there is no delay. How can i fix the issue. Songs scene consist of many graphic sprites.
When you first start your game, create an Intro Scene showing a splash image or loading image, etc. While that scene is showing, load up the resources that will take a long time to load so that they are already in the cache.
When they are done loading, transition to your main scene(s). The resources will already be loaded and they will go faster.
You can even create entire scenes like this, you just need a place to store them off temporarily, such as the child of a CCNode that you use for holding scenes. Then use them when you need them.
I only learned this recently. Before that I was loading them at the start of the App, which is a poor choice.
I have a game in Cocos2d with a main scene (game scene) and a button to go to a "Configuration" scene. When the user clicks on the Configuration button in the main scene I use pushScene to go tho the "Configuration" scene. The reason I use pushScene is to allow the user to resume the game where he was left off.
In the "Configuration" scene there are two options: "Cancel" and "Ok". If the user hits "Cancel" I use popScene and the game resumes where it was left of. If the user hits "Ok" I use replaceScene because I want the game to start from the beginning with the new configuration.
So, when the user hits "Ok" I know that the "Configuration" scene is replaced by the new game scene, but does the old game scene gets replaced too? Otherwise, am I doing things correctly or should I implement another way to let the game scene know whether it should resume or restart.
I want to make sure I am not leaking memory by accumulating unreplaced scenes.
The replaceScene method does what it says. It replaces the current scene. If you have 10 scenes pushed onto one another, it will replace the 10th scene and all previous scenes remain.
It's one of the reasons why I don't recommend using pushScene. It's too easy to forget a situation where scenes might get pushed more than they get popped. The other reason is that popScene can't be animated with a transition.
Btw, you can easily test this behavior if you do replaceScene after pushScene, then popScene in the newly replaced scene. You'll see the old scene popping up. Normally if you popScene with just a single scene in the stack it'll throw an assertion.
Is it possible to use a large image in Cocos2D, and allow, via swiping or pinching, for the user to zoom in and out?
I see from this post, that the max res for a Cocos2D image is 2048x2048. That is obviously larger than a device viewport, so I want the user to be able to move around the image.
I'm not creating a game, I'm making a sort of interactive biological cell, that will allow the user to tap arbitrary organelles, and see a popup of information about them.
Here is an idea of what the image will be, and obviously cramming the whole thing into a device viewport is not possible:
So really, before I delve too deep into this project, I'm just curious as to whether it is possible to use a large image, that allows the user the ability to arbitrarily move it around, and, if I can detect organelle touches, perhaps via CCSprites?
I recommend subclassing CCSprite and using your large image as the class's image. CCSprites certainly can detect touches by simply adding the basic CCTouchDispatcher delegate to the sprite's class:
[[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:-1 swallowsTouches:YES];
Then also add this method to your CCSprite subclass:
-(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event
You can do anything you want with the touches at this point, scroll or whatever suits your needs.
You could break up your image into many multiple sprites and use a CCLayer to manage touches instead, it just depends on whether you really need your image to be that large, or if the limitations for a single image are enough for you to work with, considering they are pretty large too. My method here is a lot less complicated than that.
The max texture size is limited by OpenGL ES not just coscos2d and it changes by device. However, you can load the image into more than one texture and then position and move those textures around the screen. So really you could have the appearance of an image any size you would like but programmatically you will have to manage the different sprites (tiles) of the image.
CCSptites don't detect touches. CCLayers have will get the touch events you can then do a hit test to see if it hits a givcen CCSprite.
I'm currently developing a program to show and control animated sprites on the desktopscreen. My problem is now to actually draw them onto the screen. The user should still be able to access other applications, as long as the sprite does not obstruct it.
My attempts are below and I hope, someone can point me in the right direction. I don't really care which library I need to use, as long as the performance is good enough for something around 20-30 animated sprites.
My attempts so far:
My first attempt was with Qt. I used a QWidget with a QLabel in it to show the pixmap of an object. The pixmap itself had an alpha channel and I used the "setMask(pixmap.mask()" method of QWidget to remove anything I don't want to show. But this method can't be used for rapidly shifting shapes, like moving creatures. If setMask is called all 50-100ms to change the mask to the next movementphase, then the cpu load gets to high with a lot of creatures moving at the same time.
My second attempt was to use one QWidget for all creatures. This way setMask ist called only one time and not once for every creature. It's possible to move more creatures this way, but the screen is flickering like hell when moving the mouse pointer over the creatures.
My third attempt were the XShape functions from Xlib to change the shape of each creature, but the performance is not much better then setMask.
I tried the transparency in Qt but if I use a QWidget over the whole screen the cpu load of X gets really high while moving the mouse. I don't know, if I can do something better here.
Create a QGLWidget and learn to use the OpenGL API to draw sprites within it, even if only using glDrawPixels rather than texture objects.
You certainly won't have any problems drawing a few tens of sprites, and the time spent learning OpenGL will be a good investment if you aspire to do more complex graphical things in future.
Not sure if this is your language but the ESheep is on GitHub, could get you started: https://github.com/Adrianotiger/desktopPet