I am not an expert in cocos2d....as cocos2d draw a 2d graphics than how can anyone identify one object is nearer than another from viewer??
can anyone help me....i have basic opengl graphics idea....
thanks
Rony
When you add a node to a parent, you can set its z order:
[scene addChild:aNode z:1];
A higher z order will be drawn first.
If you need to re-order a node after it's been added, you can call reorderChild:
[scene reorderChild:aNode z:3];
Related
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
I'm making a platform game, and everything was great. My sprite moved when i touched the left side of the screen, and jumped when i touched the right side. But then i decided to make it move by itself. so i added the ccmoveto function, but now it does not jump! I'm new to cocos2d but everything is working ok, except this, already searched but couldn't find the answer can someone please help me?
I tried everything, but it only jumps if i delete the ccmoveto action.
I'm using cocos2d 2.0
Thank you!!
CcMoveTo will override any manual position changes, inluding changes from other actions like CCJump. Your character is set to move to destination in a straight line, no matter what.
It's issues like these why I always recommend not to use actions for gameplay logic. Especially position, you need to retain full control over it. Use a direction vector and integrate position every update: and you're free to do everything you need.
my advice is to use one of the physics engines provided with cocos2d: Box2D and Chipmunk physics. Thanks to this engines you can define the characteristics of the world (i.e. gravity vector) a shape and a mass for your sprite (i.e. a rectangle with a weight). Then when you need it to jump you will just create a force vector with the characteristics you need (i.e. angle, etc.) and keep updated your sprite with its physical body. This will make your sprite jump and land quite realistically.
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];
}
I'm trying to control the order in which CCSprites are being layered one on top of the other. I'd use zOrder, but I'm animating characters made up of articulated sprites (some sprites parented on others with addChild) and zOrder is only honored among sibling sprites.
Basically, I want to parent my sprites so they can inherit each others' transforms, but I want to determine the draw order.
Looking around, it sounds like using a CCSprite's vertexZ property is the way to go. I've tried that. I set the draw method of my custom CCSprite like so:
- (void)draw
{
glEnable(GL_BLEND);
CHECK_GL_ERROR_DEBUG();
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
CHECK_GL_ERROR_DEBUG();
[super draw];
glDisable(GL_BLEND);
}
Each of my sprites now has a zOrder of 0 and a unique vertexZ to layer them as I'd like, but it's not working: any sprite that has a parent is not displayed!
Trying some things, I find if I don't set vertexZ, all sprites are displayed. And if I keep the vertexZs and don't parent, they're all displayed. But with vertexZs set, any child sprite won't display.
What's going on here and how can I get it to work?
Update: More clues. I can comment out the GL functions around my call to [super draw] entirely and the results are the same. Also, it turns out child sprites with a vertexZ do display, but wherever they overlap any other sprite they go invisible. The purple paper sprite is a child of the creature's left forearm sprite (on screen right) yet should go on top of it.
For the picture above, I'm basically doing this in my CCLayer. I want the parenting, but I want hand and paper to be on the top.
[self addChild:lUpperarm];
[self addChild:lForearm];
[self addChild:face];
[self addChild:rUpperarm];
[self addChild:rForearm];
[lForearm addChild:handAndPaper];
lUpperarm.vertexZ = -100;
lForearm.vertexZ = -99;
face.vertexZ = -98;
rUpperarm.vertexZ = -97;
rForearm.vertexZ = -96;
handAndPaper.vertexZ = -95;
This is how I want it to look. (I changed the last line to [self addChild:handAndPaper] which loses lForearm's transformations, not what I want.)
Update 2: Some have suggested I add all children with zOrder set to -1: e.g. [lForearm addChild:handAndPaper z:-1]. This changed things a little, but still didn't fix it, alas. Seems either vertexZ is not determining draw order and/or the blending is wrong.
I dealt with this issue when writing an RPG with Cocos2d. The problem is the alpha blending. As you are seeing, the paper is being covered up by the left arm sprite, even though it is transparent. For some reason, when Cocos2d's vertexZ technique is used, this problem can sometimes occur. To fix it, you can try changing your alpha blending level. Try 0.0, 0.5 and 1.0:
-(void) draw
{
glEnable(GL_ALPHA_TEST);
glAlphaFunc(GL_GREATER, 0.0f);
[super draw];
glDisable(GL_ALPHA_TEST);
}
If that doesn't work, then I recommend a complete workaround solution. Keep all your sprites as part of the same parent node and use regular z ordering. It's not an ideal solution, but if you use a "meta" parent node then you can still transform all the children easily.
While adding only u can control z-order?
[self addChild:lUpperarm z:1];
[self addChild:lForearm z:2];
[self addChild:face z:3];
[self addChild:rUpperarm z:4];
[self addChild:rForearm z:5];
[lForearm addChild:handAndPaper z:6];
I can't be sure that this is your problem but I've had issues in the past when playing with draw() and it turned out to be that I wasn't resetting the blendfunc at the end of the call.
Here's a draw function I use that does some basic drawing with some transparency. Again, no guarantees.
- (void) draw {
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
ccDrawSolidPoly(vertices, 4, fillColor);
// This is the important bit. Must do this last.
//
glBlendFunc(CC_BLEND_SRC, CC_BLEND_DST);
}
set higher z value to set object on top. and lower z value to set in back..
Hello to all I have searched many forums and cannot seem to find an answer to my question. I know that this forum is not particularly for chipmunk or spaceManager but I figured that I would see if I could get any help. My question is, I am making a simple game were the user tries to throw the football threw the center of the tire. I have created two poly shapes for the top and the bottom of the tire which I am wanting to attach to a single tire sprite. I don't know how to attach two shapes/body's to one sprite and have it attach to the top and bottom and still be able to move the sprite and use it for collision? If possible some sample code would be of great help! thanks. Here is how I am creating my shapes and sprites:
//UPPER HALF TIRE
[smgr addPolyAt:cpv(70,195) mass:STATIC_MASS rotation:0 numPoints:6 points:cpv(2,12), cpv(28,8), cpv(33,0), cpv(36,-10), cpv(-33,-10), cpv(-20,8)];
//LOWER HALF TIRE
[smgr addPolyAt:cpv(70,125) mass:STATIC_MASS rotation:0 numPoints:7 points:cpv(34,8), cpv(31,0), cpv(25,-9), cpv(7,-13), cpv(-20,-8), cpv(-30,0), cpv(-35,8)];
//Adding the Tire
CCSprite *backTire = [CCSprite spriteWithFile:#"TractorTireBack.png"];
backTire.position = ccp(70,160);
[self addChild:backTire z:1];
I know that I can attach one image to a shape like this:
cpShape *shape = [smgr addPolyAt:cpv(70,195) mass:STATIC_MASS rotation:0 numPoints:6 points:cpv(2,12), cpv(28,8), cpv(33,0), cpv(36,-10), cpv(-33,-10), cpv(-20,8)];
[super initWithShape:shape file:#"TractorTireBack.png"];
But how would I go about attaching two shapes to this one image? WIth one of the shapes being at the top and the other at the bottom.
do you want the tire to move? If the answer is no you could just leave the two cpShapes as they are and just add a standard CCSprite and position it in place.
Use
[self addChild:[smgr createDebugLayer]];
to make the cpShapes visible.