Collecting Points in Arrays?

cocos2d-x C++
#1

Hi there, I’m getting use to the Classes in Cocos and the C++ syntax and I’m a little confused about how can I store Points in an array, or use the Vector Class to do something like -seudo code-: PointArray* pointArray = {}, and then be able to iterate the array and get the stored info.

myClass.h

// Create a Pointer to the Sprite Class in my Class head
`Vector<Sprite*> _pointArray;`

myClass.cpp

//Some trigger in the implementation will populate the array
    int count;
            int i;
            float coinPosX;
            float coinPosY;

            Point point = Point(Vec2(0.8f, 0.2f));
            _pointArray.pushBack(point);

            Point point = Point(Vec2(0.5f, 0.5f));
            _pointArray.pushBack(point);

            Point point = Point(Vec2(0.2f, 0.8f));
            _pointArray.pushBack(point);

            count = (int)_pointArray.size();

            for (i = 1; i < count; i++){

                auto coinPos = _pointArray.at(i);
                coinPosX = coinPos.x;
                coinPosY = coinPos.y;
                auto coin = Sprite::create("coin.png");
                coin->setPosition(Vec2(coinPosX, coinPosY));
                this->addChild(coin);

            }

Thanks for any guideline on this topic. Greetings.

#2

You are storing them just fine. Are you having a specific problem?

#3

Just for you to know I declared the point just once, and then I just changed it values because there is an error of multiple instantiation of the Point point.

Point point = Point(Vec2(0.8f, 0.2f));
_pointArray.pushBack(point);

point = Point(Vec2(0.5f, 0.5f));
_pointArray.pushBack(point);

point = Point(Vec2(0.2f, 0.8f));
_pointArray.pushBack(point);

This is the error. I’m using Visual Studio and It’s marking the error exactly at the point before the method pushback

_pointArray.pushBack(point);

Error: No instance of overloaded function ‘’cocos2d::Vector<t>::pushback[with T=cocos2d::Sprite*]
matches the argument list

arguments types are(cocos2d::Point)
object type is cocos2d::Vector<cocos2d::Sprite*>;

What could it be the problem? Thanks for your time.

#6

Sure. You have told the compiler to expect that this Vector holds Sprite objects. But you are putting Point objects in it. A Point is not a Sprite

#7

Yep, so I tried Point instead Sprite like: Vector<Point*>

and there was the same error, but now with Point

cocos2d::Vector<cocos2d::Point*>

And then I tried just with Sprite and Point in the Header and I have the error that Expression must have a Class type

Sprite* _pointArray;
//Then
Point* _pointArray;

So what could it be the right way to create a Points Array?

#8

Why are you even trying Sprite?

just use an std::vector. It can store whatever you want.

#9

You are storing cocos2d::Point “pointers” not the values.
You are creating Point which is not a pointer (without the *).
Solution:
use cocos2d::Vector<cocos2d::Point>
instead of cocos2d::Vector<cocos2d::Point*>

#10

and not Sprite!!

#11

I am not sure why he even trying to store “cocos2d::Point” in Sprite* vector, that doesn’t make sence (unless I missed while he edited something?)

#12

No, I’m not trying to store Points into Sprites, I just don’t know how to store points and I started with Sprites. I have not a strong background on C++, and this <> is kind weird to me and I’m getting used to the whole thing Cocos2d + C++ :slight_smile: . So std:vector is like an all terrain container, that’s great to know, How can I declare this in my head? Greetings

Seudo code: PointsContainer or Points Array* _pointsArray; So I can store points or vectors.

#13

No you were trying to store Point into a Vector that was expecting Sprite i.e you declared this this:

Vector<Sprite*> _pointArray;

and were then trying to stuff a Point into it:

Point point = Point(Vec2(0.8f, 0.2f));
_pointArray.pushBack(point);

You declare an std::vector the same way you do a Cocos2d::Vector.

Please review: http://www.cplusplus.com/reference/vector/vector/

1 Like
#14

I’ve overview the reading and I can see that Vectors can work as an array, thanks for the guideline. In this case this vector contains an array that expects Points:

Vector<Point> _pointArray;

The implementation is still the same but I got this error:

Invalid Type for cocos2d::Vector<T>!

int count;
        int i;
        float coinPosX;
        float coinPosY;

        Point point = Point(Vec2(0.8f, 0.2f));
        _pointArray.pushBack(point);

        point = Point(Vec2(0.5f, 0.5f));
        _pointArray.pushBack(point);

        point = Point(Vec2(0.2f, 0.8f));
        _pointArray.pushBack(point);

        count = (int)_pointArray.size();

        for (i = 1; i < count; i++){

            auto coinPos = _pointArray.at(i);
            coinPosX = coinPos.x;
            coinPosY = coinPos.y;
            auto coin = Sprite::create("coin.png");
            coin->setPosition(Vec2(coinPosX, coinPosY));
            this->addChild(coin);

        }
#15

you need to specify std::vector that error tells me you are still declaring a Cocos2d::Vector

Also, take a look at cpp-tests for help

#16

Oh yeah, I’ve seen that the Cocos Vector Class works slightly different than the Std class. So I declared std::vector<Point> _pointArray in my head; but pushBack is not a member of the std::vector class so there is an error telling me so. Thanks for any guideline.

#17

your answer is in that link I posted about std::vector.

You are going to have a very hard time if you don’t learn more c++ or at least know how to start solving your problems when they arise.

#18

Thanks for your time. Greetings.