Messages

1

Graphics / Re: SFML and Box2D

« on: March 10, 2014, 11:35:24 pm »

Got it fixed with adding this line after setOrigin()  !

setPosition(getPosition().x + getGlobalBounds().width / 2, getPosition().y + getGlobalBounds().height / 2);

...but it feels somehow like a "dirty" solution....

Added a picture of the current state

2

Graphics / Re: SFML and Box2D

« on: March 10, 2014, 09:49:51 pm »

I added it to the b2_init method, sooooooo.... yes, the Origins of the Tiles should be set, too ^^

3

Graphics / Re: SFML and Box2D

« on: March 10, 2014, 09:28:53 pm »

First of all: Thanks for the DebugDraw idea, it is very useful!

Like suggested, I also tried to use setOrigin() and it corrected the position of the players, unfortunately it had absolute no effect on the tiles (b2_staticBodies), see the images.

I used the following code:

setOrigin(getGlobalBounds().width / 2, getGlobalBounds().height / 2);

Why are the tiles not affected, why are they still shifted ?_?

btw. could it be, that i also have to turn over the y-axis?
   

4

Graphics / AW: Re: SFML and Box2D

« on: March 09, 2014, 10:50:12 pm »

Wow, that was fast! ^^

Thanks a lot,
I will try this tomorrow and report:

I believe Box2d used the object's centre of mass as its position. sf::Sprite use the top left corner by default, so you should use sf::Sprite::setOrigin to correct for that.

realloc()

5

Graphics / SFML and Box2D

« on: March 09, 2014, 08:52:11 pm »

This is my first post here....
-> so "Hi" to everyone :D

I am currently writing a platformer like game, which I want to be playable for two or more persons.
Because I need  good physics for it (Players should be able to push each other into traps etc.) I replaced my own poor physics with Box2D.

Unfortunally it behaves a bit weird, because the Box2D world seems always to be a bit shifted to the rendered world, so that the characters are half in the ground (see image).
Besides that i use a tilemap and the characters are sometimes stuck between two tiles, although they are on the same level....

The function which converts my map object into a b2World looks like this:

Piece #1:
(out of map converter)

Given Variables:

    b2World world;
    std::vector<extendedSprite *> const & tiles; //<- extendedSprite inherits from sf::Sprite
    std::vector<playerClass *> const & players; //<- playerClass inherits from extendedSprite

Code Piece:
   

size_t i;
    extendedSprite * eSpritePtr = NULL;

    //Convert Tiles
    for (i = 0; i < tiles.size(); i++)
    {
        eSpritePtr = tiles.at(i);

        eSpritePtr->b2_init(world, b2_staticBody);
        eSpritePtr->physBody->SetSleepingAllowed(true);
        eSpritePtr->physBody->SetAwake(false);
    }

    //Convert players
    for (i = 0; i < players.size(); i++)
    {
        eSpritePtr = players.at(i);

        eSpritePtr->b2_init(world, b2_dynamicBody);
        eSpritePtr->physBody->SetFixedRotation(true);
    }

Piece #2:
(out of extendedSprite Class)

Given variables:

b2Body * physBody;
float xVelocity; //Of the Sprite
float yVelocity;
 

Code piece:

void extendedSprite::b2_init(b2World & world, b2BodyType bodyType)
{
    b2BodyDef def;
        def.position = SF_B2_Translator::toB2Vector(getPosition()); //"Converts" Pixels to Meters by dividing them by 48
        def.type = bodyType;
        physBody = world.CreateBody(&def);

    b2FixtureDef fixtureDef;
        b2PolygonShape shape;
            shape.SetAsBox( SF_B2_Translator::toMeters(getGlobalBounds().width / 2), SF_B2_Translator::toMeters(getGlobalBounds().height / 2)); //Again pixel to meter conversion

        fixtureDef.density = 70.f;
        fixtureDef.friction = 0.7f;
        fixtureDef.shape = &shape;
        physBody->CreateFixture(&fixtureDef);

    if (bodyType == b2_dynamicBody)
    {
        physBody->SetLinearVelocity(b2Vec2( SF_B2_Translator::toMeters(xVelocity), SF_B2_Translator::toMeters(yVelocity)));
    }
}
 

...
Later i update the player like this:

       

xVelocity = SF_B2_Translator::toPixels(physBody->GetLinearVelocity().x); //"Converts" Meters to Pixels by multiplying by 48
        yVelocity = SF_B2_Translator::toPixels(physBody->GetLinearVelocity().y);

        setPosition( SF_B2_Translator::toSFVector(physBody->GetPosition()));

...
(Hope that wasn't to much code...)

I can't find my mistakes..... Do you have any ideas?

Is Box2D a good choice at all, if i want my game to be playable over network later?

Thanks in advance,
realloc()

P.S. Sry for my bad English......