Since Cocos2d v2.0 no longer has honorParentTransform, what should we use?
Inverted rotations do not work for particles.
Don't add it as child but to the same parent. Then synchronize position every update.
PS: honorParentTransform may still exist under a different name, check the API reference for CCNode properties.
Related
I have implemented a QGraphicsScene to contain instances of QGraphicsItem of a few different classes implemented by me. What I still don't understand is how the QGraphicsView associated with this scene is updated.
When I call addItem(QGraphicsItem) the scene seems to redraw displaying the newly added items.
When I change properties of my QGraphicsItem instances (e.g. calling setVisible(bool)) it seems that the view is not updated automatically.
I currently call QGraphicsScene::update() without any arguments to draw the new state. this works in most cases, however in some of them it fails ( QGraphicsItem's paint() method is not called. I set a breakpoint there but whether it is reached or not depends on the zoom level in the QGraphicsView. I have to zoom out to a certain level for it to get called again).
It doesn't work when I pass the bounding box of the changed item (scene coordinates) to QGraphicsScene::update(QRect). I can't see objects changing.
Can anybody give me a hint what is the correct way of implementing this? How do I notify the view correctly of changes in certain areas, what does the behaviour depend on. I think there's something wrong with my assumptions about coordinate systems. Thanks a lot for your explanations.
I add some nodes that move around the screen. at some point, when I press a button (MenuItemImage), I need to change layer (not scene). So, I try to remove all moving nodes' PhysicBody from the PhysicWorld and then, remove nodes themselves. It works usually, but sometimes, I get crash from inside of PhysicsBody::update function. at that point, this refers moving object PhysicBody. and, it seems parent is NULL. But, I try all PhysicBody from the World. So, after I remove, they should not be drawn (I guess this is causing the problem)
It is too obvious that there are some concurrency problem. but, I don't want to touch cocos2d-x dispatcher. so, what is the proper way to remove a PhysicBody and node from the world.
now, I call removeFromWorld() for PhysicBody and removeChildren for Cocos2d node. Even, I put some delay between these two operation, I still get crash sometimes.
I'm making an endless running game in which users dodge obstacles, and I'm working on producing the obstacles right now. The plan I had where I'm spawning these obstacles is as follows:
obstacle->setPosition(CCPointMake(this->getContentSize().width, this->getContentSize().height*.75));
obstacle->setScale(.5);
this->addChild(obstacle);
_obstacles->addObject(obstacle);
obstacle->runAction(CCMoveBy::create(2.0, CCPointMake(-(this->getContentSize().width + obstacle->getContentSize().width/2), 0)));
obstacle->removeFromParent();
I set the position, set it's scale, add it to the scene, run an action on it so that it moves across the screen from right to left, add it to an array called _obstacles to be used elsewhere, and then I remove it from the scene so as to save memory. However, the problem is that once I try implement this, the obstacle doesn't show up at all as if it's nowhere to be seen. When I don't call obstacle->removeFromParent() it shows up and performs the action. What am I doing wrong here? If I don't call removeFromParent(), what do I call? Is there a problem in my code not related to removeFromParent()?
The reason that obstacle doesn't apeear at all is that it is removed as it start moving. You just have to create a sequence of move action and function call with obstacle as parameter and than remove this obstacle in that function , so that obstacle will be removed after moving out of screen.
CCCallFuncN *myCallFunc = CCCallFuncN::create(this, callfuncN_selector(CLASS_NAME::removeObstacles));
obstacle->runAction(CCSequence::create(CCMoveBy::create(2.0, CCPointMake(-(this->getContentSize().width + obstacle->getContentSize().width/2), 0)),myCallFunc,NULL));
Method to remove obstacle from array and from parent view
void CLASS_NAME::removeObstacles(CCObject* pSender){
// Type cast pSender to obstacle type e.g if obstacle is of CCSprite type.
CCSprite *tempObstacle = (CCSprite *)pSender;
_obstacle.pop_back(tempObstacle);
tempObstacle->removeFromParent();
}
Don't forget to replace CLASS_NAME by your class name
I would need more info on what removeFromParent is doing and how you use _obstacles
I'm taking a guess on how the parent is structured. I would guess that it has a list of children and when the parent is updated/render, it calls those functions for its children. If removeFromParent removes the object from its parent list, then that would explain why it is not being render or used in the scene. If you have a setup like this, then you should only call removeFromParent before destroying the parent object
I have a dialog.cpp file, it is within here I created my QGraphicsScene which uses the QGraphicsView.
I created two classes that inherit QGraphicsPixmapItem, "Vehicle" and "Junction". Both of these objects are added to the same QGraphicsScene in my dialog.cpp file.
I want to call a method which is a member of "Junction" from my "Vehicle" object. The method returns a boolean value which I need.
This is more of a c++ orientated question, as I'm sure there's an easy solution which makes use of accessing a parent.
Background info on project: Each "Vehicle" moves along a road and approaches a "Junction". The vehicle must then ask the junction "does my lane have a green light to go?", the junction will then reply "true/false".
After reviewing possible solutions via the QT documentation I have partly resolved the issue.
Calling this->scene() allows access to member functions of the scene, on which your object was added. Since I know the co-ordinates of my object I call, this->scene()->itemAt(240,0); to retrieve a pointer to the item.
The pointer returned is the uppermost item on the scene at the co-ordinates supplied. If this provides a problem alternately use scene()->items() to retrieve a list of all the items on the scene.
However, this only gives access to the item and not the vector in which the item is stored. I have been looking into using the ->parent() function and think this may be the solution, combined with dynamically casting it to the required pointer. Will update the answer if I find a full solution.
I am making a top-down shooter that makes extensive use of TMX maps created with the "Tiled" application. Within my TMX map, I have a "Background" layer with floor tiles, which appears beneath my characters (CCSprites.)
I have another layer in the TMX file called "Foreground" which I would like to appear "above" my CCSprites, giving the illusion of them walking underneath various objects.
I tried using the vertexZ property of the CCNode class to do this:
CCTMXLayer *backgroundLayer = ...
CCSprite *spriteNode = ...
CCTMXLayer *foregroundLayer = ...
[backgroundLayer setVertexZ:1];
[spriteNode setVertexZ:2];
[foregroundLayer setVertexZ:3];
...but it turns out vertexZ actually alters the node's visual appearance within the openGL view. It effectively causes a CCNode to appear larger, or closer to the user when it has a higher vertexZ value. I don't want that- all I want is a sort of layers-of-an-impossibly-thin-cake effect, without any visual differences between the layers.
So I thought I would try altering the zOrder property of the nodes, like this:
[[backgroundLayer parent] reOrderChild:backgroundLayer z:1];
[[spriteNode parent] reOrderChild:backgroundLayer z:2];
[[foregroundLayer parent] reOrderChild:backgroundLayer z:3];
But I realized there's a fundamental problem with what I'm doing here, since my spriteNode is a direct child of the CCScene, but the background and foreground nodes are both children of my CCTMXTiledMap, which itself is a child of the CCScene.
So I'm basically trying to slip a CCSprite between two layers of the map, which, from the CCScene's perspective, are really just two parts of the same layer.
It seems I could create an additional instance of CCTMXTiledMap just to hold the foreground layer, but that also seems like overkill. My other thought was to create CCSprites to serve the same purpose, but it seems like there's got to be a better way.
Yes, I have used Tiled once very lightly and I do believe there is an option to add an Object Layer into your TMXTiledMap (Tiled -> Layer -> Add Object Layer...), then once imported into your build you can link up a CCSprite with the corresponding Object Layer you have created. I would post your question on the cocos2d forum, as people there are more experienced and equipped to answer this with examples.