A fast, easy to use, free, and community supported 2D game engine
DenisRedis
Member
First sorry for my bad english.My question is: how in box2d I can add texture on polygon, I make poligon use b2Vec2 something like:
b2Vec2 vertices[count1];
vertices[0].Set(5.0f,2.0f);
vertices[1].Set(2.0f,1.0f);
vertices[2].Set(2.0f,0.0f);
vertices[3].Set(5.0f,-1.0f);
b2PolygonShape polygon;
polygon.Set(vertices,count1);
but when I wold use CCSprite to add image to polygon nothing happens
chrisco
Member
Take a look at the Box2d template that comes with Cocos2D, specifically in the -(void) addNewSpriteWithCoords:(CGPoint)p method - you don't actually apply a texture to a Box2d object, you assign a sprite to a b2Body's userData member, like so:
bodyDef.userData = sprite;Now look at the -tick: method that gets called on every frame. Here is where all the bodies in the world are looped through, and the position/rotation of the sprites are updated to sync with the physics bodies.
//Iterate over the bodies in the physics world
for (b2Body* b = world->GetBodyList(); b; b = b->GetNext())
{
if (b->GetUserData() != NULL) {
//Synchronize the AtlasSprites position and rotation with the corresponding body
CCSprite *myActor = (CCSprite*)b->GetUserData();
myActor.position = CGPointMake( b->GetPosition().x * PTM_RATIO, b->GetPosition().y * PTM_RATIO);
myActor.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle());
}
}Hope that helps.
Chris
DenisRedis
Member
I want to assign a sprite to my polygon, using
bodyDef.userData = sprite;
My question is how to create a sprite which would match my polygon's shape, or more generally, how to cover a polygon with texture. You can look at it as splitting the screen at some (random or predefined) pattern of polygons, and every polygon needs to be covered with texture. I don't think that making a separate image for every polygon and explicitly assigning a sprite to every polygon would help, because I am going to have many of those. So what I need is some way of taking a texture and getting pieces of this texture as sprites, and assigning them to my b2PolygonShape polygons (perfectly - on runtime, so I could make polygons with random vertices, but not sure if this is possible at all?). In box2d template, there is a sprite sheet of 4 square boxes, and in function -(void)addNewSpriteWithCoords:(CGPoint)p one of the box images is picked and assigned as a sprite to a polygon. How would you "cut out" a non-rectangular shape?
Hi,
I am facing the same problem. I am creating a body like:-
b2BodyDef myBodyDef;
myBodyDef.type = b2_dynamicBody; //this will be a dynamic body
myBodyDef.position.Set(2, 2); //set the starting position
myBodyDef.userData = cart;
myBodyDef.angle = 0;
dynamicBody = world->CreateBody(&myBodyDef);
b2Vec2 vertices[5];
vertices[0].Set(0, 0);
vertices[1].Set(3, 0);
vertices[2].Set(3, 0.5);
vertices[3].Set( 1.5, 1);
vertices[4].Set( 0, 0.5);
b2PolygonShape boxShape;
boxShape.Set(vertices, 5);
b2FixtureDef boxFixtureDef;;
boxFixtureDef.shape = &boxShape;
boxFixtureDef.density = 0.1;
dynamicBody->CreateFixture(&boxFixtureDef);
But the centre point of sprite and body is not matching. i want to change the centre point of my sprite with respect to body.
Thanks In advance.
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