CODEWITHSUNDEEP
javaandroidvectorlibgdxphysics
Biggytiny
Biggytiny

Reputation: 529

Moving Body using force in Libgdx based off of touch input

What I am trying to do is take in an inputted user touch down, convert the camera coordinates of the touch down to world coordinates, then create a vector to use in order to apply force to my body. This is what I have for that:

    Vector3 worldPos = new Vector3(newX, newY, 0);
    GameScreen.gameCam.unproject(worldPos);

    newX = worldPos.x;
    newY = worldPos.y;

    Vector2 direction = new Vector2();

    direction.set((newX - xPos), (newY - yPos));
     if (newX <= xPos){
        direction.set((xPos - newX), (yPos - newY));
    }

    b2Body.applyForceToCenter(direction, true);

I know that this really isn't right at all as far as creating the vector goes, but the coordinates are being converted properly.

So my question is, how can I get an accurate vector, even in the negative direction, when I have both the world coordinates of the body and touch down?

I have tried doing some research to get a better understanding of all of this but I am having a bit of trouble. Any help would be greatly appreciated, thank you for your time.

Upvotes: 0

Views: 128

Answers (1)

Radosław Bojba
Radosław Bojba

Reputation: 21

If you have on newX, newY screen touch coordinates and next change it to world coords you can get direction by subtraction touchWorldPos to currentObjectPos:

Vector3 worldPos = new Vector3(newX, newY, 0);
GameScreen.gameCam.unproject(worldPos);

newX = worldPos.x;
newY = worldPos.y;

Vector2 direction = new Vector2();
direction.set((newX - xPos), (newY - yPos));


b2Body.applyForceToCenter(direction, true);

without this if statement:

 if (newX <= xPos){
    direction.set((xPos - newX), (yPos - newY));
 }

in box2d this direction might have small values and you must muliply this one by some value like 100(mayby more)

Upvotes: 1

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