I am designing a game in which I have used 40 CCSprite objects. I need to detect the collision in between them. I am able to detect the collision between 2 sprites. Now how can i check 1 objects against all the remaining objects? Is using a FOR loop will work? or is there any other way to do this?
I think for a first iteration you should implement the for loop and see if it's fast enough.
If it's not, I guess you could partition your game area into rectangles and distribute your objects to rectangles (an object that overlaps multiple rectangles belongs to all of them). Then when you do the collision you can check only in the rectangle where your initial object is placed. Of course this depends a lot on what you have there. If all objects move around a lot it might not be such a hot idea.
Why dob't you use Box2D or chipmunks
For Box2D this link will help.
For Cocos2D following code will help.
You need to add following lines
shape->collision_type = kCollisionTypeParticle;
cpSpaceAddCollisionHandler(space_, kCollisionTypeParticle, kCollisionTypeParticle, collisonDetect, NULL, NULL, NULL, self);
Here collisonDetect is a method we need to register as:
cpBool collisonDetect(cpArbiter *arb, struct cpSpace *space, void *data)
{
*layer = ( *)data;
[layer collisonDetect:arb];
return cpTrue;
}
Now here here you will handle rest of the code
-(void)collisonDetect:(cpArbiter*)arb
{
NSLog(#"COLLISION DETECTED");
}
Related
I'm attempting to make a Space Invaders clone. In doing so I'm having a difficult time grouping the invaders together so that they move at the same time.This is due to both CCLayer and CCNode being deprecated in v3.1 in cocos2dx. I saved my sprites to a vector that I can iterate over but when I attempt to move them only move one at a time. I need to group them together so I can move them all at once.
void Gameplay::moveInvaders(){
auto moveLeft = MoveBy::create(2, Vec2(-1, 0));
auto moveRight = MoveBy::create(2, Vec2(1, 0));
auto moveDown = MoveBy::create(2, Vec2(0, 1));
auto stay = MoveBy::create(20, Vec2(0,0));
// create a sequence with the actions and callbacks
auto seq = Sequence::create(moveLeft, stay, moveRight, stay, moveDown, stay, nullptr);
for (int i = 0; i < invaders.size(); i++) {
invaders.at(i)->runAction(seq);
}
Update: I ended up figuring out the issue. Instead of trying to use the sequence I ended up scripting the movements with some control logic and the system timer.
Add this to your init() function:
this->schedule(schedule_selector(Gameplay::moveInvaders), 1.0);
Of the form:
this->schedule(schedule_selector(<Class_Name>::<function_To_call>), <number_of_frames_to_run>);
Then decide what you want to do in your function that will be called that often. I used a couple of boolean and int values to keep a counter. That way I could control the direction the invaders would move.
Hopefully this helps somebody else! I couldn't find what I needed to know because most of the tutorials for cocos2dx were in Objective-C or Javascript.
How about adding all invaders into one sprite, say "InvaderGroup"? All transformations (and need to refer once, but most probably all Actions too) to a sprite are guaranteed to be calculated on children too, so no worries, I suppose.
So many invaders individually watching out for events sounds like overhead, especially the result movement is not supposed to be individually decided. You can use your own Sprite subclass if you prefer, but just to move them around it's not necessary.
P.S.
Your invaders will still be able to roam individually if you want them to, just the co-ordinates will be with reference to the parent Sprite.
I'm working on a game project in c++ using programming oriented object and classes but I can't figure out a way to animate the following graphics.
What I need is while the player is holding left key or the right key, the graphics should be appearing to make the character like moving and when they stop holding the key it'll turn to idle graphic.
I can't paste the whole source code here, i have many classes, and functions.. All I need is a BASIC idea of how to implement it, an example or a function anything useful. I don't need libraries because i just have two sprites to animate so it's not necessary.
As an example be Sprites the class that creates the object and Koala the one that moves it and prints it in a certain position.
Sprites idleSprite, walkingSprite;
Koala koala;
These declarations are just for avoiding other explanations.
I would appreciate your help.
PD: Don't worry about the keyboard keys, or other classes all I need is how to animate a sprite.
Koala should have two states:
a direction state: enum Direction {Left,Right};
a movement state. enum Movement { Idle, Walk };
As you have only one picture for the walking status, moving graphically the picture around will give the impression of a floating body. I'd recomment that you'd really have at least two walking positions to show that the foots are moving:
a movement step counter
a constant for the maximum number of steps.
Then the states should be updated in your game loop according to keyboard status and elapsed time. The pseudo code would be something like:
if (!arrow_key_pressed()) {
status_movement = Idle;
lasttimer = gametimer(); // keep track of last event
}
else {
status_movement = Walk;
if (left_arrow_pressed() )
status_direction = Left;
else if (right_arrow_pressed() )
status_direction = Right;
if (gametimer() - lasttimer > 2 ms ) { // if enough time,
if (status_direction==Left)
position_x -= step_increment;
else if (status_direction==Right)
position_x += step_increment;
movement_step = (movement_step+1) % maxi_steps;
lasttimer = gametimer();
}
}
All you have then to do is to restore te background of the picture at tis old position, and draw the picture at the position. For this, youd could call a function with paramters position_x, direction, movement status and status step, to return/draw the sprite at the right place.
I am fairly new to VTK and I really enjoy using it.
Now, I want to interact with multiple objects independently. For example, if I have 5 objects in a render window, I want to only move, rotate and interact with the one selected object; whilst the rest of the 4 objects stay where it is.
At the moment, the camera is doing the magic and as I rotate the independent object, other objects move at the same time and I don't want that to happen.
I also want to store all the objects in memory.
I intend to use C++.
This is my sort of class structure...
class ScreenObjects
{
vtkActor (LinkedList); // I intend on using a linkedlist to store all the actors
public:
ScreenObjects(); // Constructor. Initializes vtkActor to null.
void readSTLFile(); // Reads the STL File
bool setObject(); // Sets current object, so you can only interact with the selected object
}
I am missing quite a lot of functions and detail in my class, as I don't know what else to include that would be of use. I was also thinking of joining two objects together, but again, I don't know how to incorporate that in my class; any information on that would be appreciated.
Would really appreciate it if I could be given ideas. This is something of big interest to me and it would really mean a lot to me, and I mean this deep down from my heart.
First of all you should read some tutorials and presentations like this one for example:
http://www.cs.rpi.edu/~cutler/classes/visualization/F10/lectures/03_interaction.pdf
I say that cause it looks like you're currently just moving the camera.
Then you should look into the VTK examples. They are very helpful for all VTK classes.
Especially for your problem have a look at:
http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/Picking
Basicly you have to create a vtkRenderWindowInteractor derived class to get the mouse events (onMouseDown,onMouseUp,onMouseMove,...).
And a vtkPropPicker to shoot a ray from your mouse position into the 3D view and get the vtkActor.
Now you can store onMouseDown inside your vtkRenderWindowInteractor derived class the vtkActor you'd like to move and the currentMouse position. When the user release the mouse (onMouseUp) just get the new mouse position and use the difference of the onMouseDown/onMouseUp positions to modify the vtkActor position.
I have read this page to understand batch drawing details, but I still have questions. I know that in order to reduce draw call number we need to use batch drawing. I use it like this:
auto spritebatch = SpriteBatchNode::create("ingame.png");
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("ingame.plist");
And now I need to create a Sprite I have to do this:
auto backgroundSprite = Sprite::createWithSpriteFrameName("back_gradient.png");
spritebatch->addChild(backgroundSprite);
But I don't understand the following things:
What if my game has several spritesheets. For example I have HUD spritesheet and ingame spritesheet. Now if I want to show ingame screen with HUD then I need to create 2 SpriteBatchNode? and add them into ingame layer?
What if the same spritesheet should be used in different Scenes. Should I do the following again?
auto spritebatch = SpriteBatchNode::create("ingame.png");
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("ingame.plist");
What if I use sprites with Button, TextEdit, Label and other UI elements.
First of all can I initialize Button state images from spritesheet?
As I know I cannot add UI element as a child to SpriteBatchNode. In this case how to combile UI elements and sprite in the same view/scene?
Sorry for lots of questions. But the fact is that I could not find any resource that contains the explanations to this questions. While they are all related. If you don't know answers to these questions, you don't know how to use SpriteBatchNode.
Don't use CCSpriteBatchNode in cocos2d-x v3. Batching is automatic and best left to the renderer to optimize draw calls through batch drawing. It says so right in the article you've linked:
The Render graph was decoupled from the Scene graph.That means that auto-batching is supported, finally :-) And the new renderer is so fast, that we no longer encourage the use of SpriteBatchNode.
I don't agree, depending not how fast new render is we want to get most of it as we can.
Narek, you are correct.
During rendering the geometry will be sorted to reduce the quantity of GL calls. But don't expect it will sort children of different parents in one line. Example: you have
Node A with children ab and ac
Node B with children bd and be.
if b and d uses textures of same atlas it is not guaranted you will get any perfomance boost of using atlases at all.
But I can confirm, currently it is really fast, and at my case the GL calls are not the bottleneck at all :)
I am at the start of my cocos2d adventure, and have some ideological questions to ask. I am making a small space-shooter game, am I right to use the following class structure?
Scene
Background Layer
Infinite parallax background
Game Layer
Space ships
Bullets
Control Layer
Joystick
Buttons
and a followup question — what is the best practice in accessing objects from other layers? For example, when the joystick is updated, it must rotate the space ship and move the background. Both of these are in other layers. Is there some recommended way to go about this or should I simply get the desired objects by Tag and operate on them?
Cocos is a big singleton-based system, which may not appeal to some developers but is often used in Cocos apps and is the fundamental architecture of the framework. If you have one main scene and many subsequent layers added to that scene, and you want controls from one layer to affect sprites or logic on other layers, there really is nothing wrong with making your main scene a singleton and sending the information from the joystick layer back to the scene to handle for manipulating other layers or sprites. I do this all the the time and this technique is used in countless Cocos tutorials in books and online, so you can feel that you aren't breaking too many rules if you do it this way (and it's also quite easy to do).
If you instead choose to use pointers in one layer to send data to other layers, this can get you into a lot of trouble since one node should never own another node that it doesn't have a specific parent-child relationship with. Doing so can cause crashes and problems with the native Cocos cleanup methods when you remove scenes later, and potentially leak memory. You could use a weak reference in such a case instead, but that is still dependent on one layer expecting another layer to always be around, which may not be the case.
Sending data back to the main game scene to then dispatch and use accordingly is really efficient.
This seems like a perfectly reasonable way to arrange your objects, this is a method I use.
For accessing objects, I would keep an explicit reference to the object as a member variable and use it directly. (Using tags isn't a bad option, I just find it can get a little messy).
#interface Class1 : NSObject
{
CCLayer *backgroundLayer;
CCLayer *contentLayer;
CCLayer *hudLayer;
CCSprite *objectIMayNeedToUseOnBackgroundLayer;
CCNode *objectIMayNeedToUseOnContentLayer;
}
Regarding tags, one method I use to make sure the tag numbers I'm assigning are unique is define an enum as follows:
typedef enum
{
kTag_BackgroundLayer = 100,
kTag_BackgroundImage,
kTag_GameLayer = 200,
kTag_BadGuy,
kTag_GoodGuy,
kTag_Obstacle,
kTag_ControlLayer = 300
kTag_Joystick,
kTag_Buttons
};
Most times I'll also just set zOrder and tag properties of CCNodes (i.e. CCSprites, CCLabelTTFs, etc.) the same, so you can actually use the enum to define your zOrder, too.