Exchanging sprite content in cocos2d-x 3 - c++

I exchange sprite content with this code:
mySprite->setTexture(Director::getInstance()->getTextureCache()->addImage("newImage.png"));
The problem is that newImage.png is much smaller than the old content image of the sprite. But cocos2d-x scales newImage.png to have the same size as oldImage.png. How I can prevent this scaling. I need newImage.png to be its natural size, but to appear in the coordinates of oldImage.png (I want to retain the same sprite object, as far as I have a pointer on it and also the same position and same anchor point. That's why I use setTexture just to change the image.)

Well, this may not be the cleanest way, but it seems the most straigthforward to me :
Sprite *newSprite = Sprite::create("newImage.png");
newSprite->setAnchorPoint(mySprite->getAnchorPoint());
newSprite->setPosition(mySprite->getPosition());
mySprite->removeFormParentAndCleanup(true);
mySprite = newSprite; // <-- magic happens here
So basically you create a new sprite, place it based in old sprites position/anchor and then after removing the old one, you assigne the mySprite variable to point to the same place as newSprite.

mySprite->setTexture("newImage.png");
This sets the content Rect too.

Related

How to add a sprite that is always on the screen in Cocos2d?

I'm doing a platformer game using cocos2d-x v3 in c++, where the maps are usually very large, the visible screen follows the object through the map.
Let's say I want to show a sprite in the top right corner of the screen and it would be in this position even when the screen is following the object.
Using the object position doesn't do it.
Is there a way to show a sprite or whatever in the screen and it would be in the screen even when the screen is moving?
Ps. I'm super noob in game development
As it's written here, you whould use convertToWorldSpace
convertToWorldSpace converts on-node coords to SCREEN coordinates.convertToWorldSpace will always return SCREEN position of our sprite, might be very useful if you want to capture taps on your sprite but need to move/scale your layer.
Generally, the parent node call this method with the child node position, return the world’s postion of child’s as a result. It seems make no sense calling this method if the caller isn’t the parent…
So, as you can read,
Point point = node1->convertToWorldSpace(node2->getPosition());
the above code will convert the node2‘s coordinates to the coordinates on the screen.
For example if the anchor position of node1 is which will be the bottom left corner of the node1, but not necessarily on the screen. This will convert the position of the node2 which is to the screen coordinate of the point relative to node1 ).
Or if you wish, you can get position relative to scenes' anchor points with function convertToWorldSpaceAR.
So there are some assumptions that will have to be made to answer this question. I am assuming that you are using a Follow action on your layer that contains your map. Check here for example. Something like:
// If your playerNode is the node you want to follow, pass it to the create function.
auto cameraFollowAction = Follow:create(playerNode);
// running the action on the layer that has the game/map on it
mapLayer->runAction(cameraFollowAction);
The code above will cause the viewport to "move" to where the player is in world position. So following the player on your map that's bigger than the current viewport. What I did for my in-game menu/hud is add the Hud onto a different layer and add it to the root of the main game scene. The scene that does not have the follow action running on it. Something like below.
// Hud inherits from layer and has all the elements you need on it.
auto inGameHud = HudLayer::create();
// Add the map/game layer to the root of main game scene
this->addChild(mapLayer, 0);
// Add the hud to the root layer
this->addChild(inGameHud, 1);
The code above assumes 'this' to be your MainGameScene. This restricts the Follow action from scrolling the element off the screen. Your element will be on the screen no matter where in World space your scene currently is.
Let me know if this is clear enough. I can help you out more if you get stuck.
I've managed to do it using a Parallax Node, and using the velocity which the sprite goes to Vec2(0,0), this way it stays always on the same spot in the screen.
You can always just put that sprite into different node / layer that everything else is. That way moving this layer / node won't move the sprite

Cocos2d CCLabelBMFont how to add a background to string

I am wondering how can I add a border & background to labels generated via CCLabelBMFont class in cocos2d.
I don't want to use sprites because my labels are generated on the fly and will keep changing and the size of labels are also different.
Also, I want user to touch and move these labels across the screen. When user picks a label it wiggles a bit like in free air. In that case, I wish to keep low complexity and preserve memory and cpu calculations.
Anyone knows best ways to achieve this?
IOS app LetterPress has similar effects.
Create your own class, that will incapsulate creation of complex node.
It will have several layers, for example, the first layer can be simple CCLayerColor of given rect with zOrder -2, the next layer will be your CCLabelBMFont with zOrder -1 and then you can overload draw method to draw border over your control. All that you draw in this method will be drawn with zOrder 0.
Then you can encapsulate any effects in this class. For example, you can rotate it a bit with method pick, etc. Whatever you want.

ccSpriteBatchNode child bounding box transformation

I'm using cocos2d 1.0.1.
I've created a CCSpriteBatchNode, it includes a CCSprite (let's name it parentLayer) which includes some X number of childs(CCSprites).
The problem is - when I rotate parentLayer all sprites (childs) correctly displayed, however bounding boxes are at the same place (where they've been before rotation), so world coordinates of those sprites won't be changed.
Off course, all of the above works great without CCSpriteBatchNode. But, I would like to use batch node due to amount of sprites involved.
The question is, is there any way to update bounding boxes & child positions correspondingly?
How many sprites are we talking about? I would just go with a fast enumeration call to rotate each one individually. I nave never noticed a performance hit when doing this, have you?
CCArray *listOfChildren = [parentLayer children];
for (CCSprite *sprite in listOfChildren) {
[sprite setRotation:someValue];
}

Cocos2d show only a part of a CCSprite

Is there any possibility to show only a part of an CCSprite?
It seams that contentSize property doesn't have a good result.
I think you might have to create a new sprite for this. The general pseudo code is this.
CCTexture2D *origTexture = originalSprite->getTexture();
CGRect rect = {0, 0, 20, 20};
CCSprite *destSprite = CCSprite::spriteWithTexture(origTexture, CGRect);
Both doc_180's and James' answers work by creating new CCSprite using a portion of the texture, but if you are using clipping method, you will get CCSprite that uses the full texture but have the ability to only draw a portion of it on screen. One advantage of this method is you are able to modify how big or small the portion that you want shown or hidden on the fly rather than having to re-create the CCSprite again and again (or replacing the texture again and again).
So, to use the clipping method, simply download the ClippingNode class from here, and add the CCSprite you want clipped to that ClippingNode. Then you call one of its methods to specify which region to limit the drawing to. I'm currently using it to create a progress bar so I know for sure it works great.
Get the [sprite displayedFrame], change the frame of that, and create a new sprite with that spriteframe: CCSprite *sprite2 = [CCSprite spriteWithSpriteFrame:frame]

Coordinate confusion

I subclassed QGraphicsItem and reimplemented paint.
In paint I wrote something like this for labeling the item:
painter->drawText("Test",10,40);
After some time I think It may be useful to handle labeling with seperate item. So I wrote something like this.
QGraphicsTextItem *label = new QGraphicsTextItem("TEST",this);
setPos(10,40);
But two "TEST" drawing do not appear in the same place on screen. I guess difference may be related with item coordinates - scene coordinates. I tried all mapFrom... and mapTo... combinations inside QGraphicsItem interface but no progress. I want to drawings to appear in the same place on screen.
What I miss?
I assume that you are using the same font size and type in both cases. If the difference in position is very small the reason can be the QGraphicTextItem is using some padding for the text it contains. I would try to use QGraphicsSimpleTextItem that is not going to add fancy stuff internally and see if you still have the same problem. The coordinates system is the same one if you use painter or setPost so that is not the problem. If this doesn't help I will suggest to specify the same rect for both to avoid Qt adding it owns separation spaces.