Sprite3D

Just like 2D games, 3D games also have Sprite objects. Sprite objects are a core foundation of any game. One of the main differences between Sprite and Sprite3D is Sprite3D objects have 3 axes it can be positioned on: x, y and z. Sprite3D works in many ways just like a normal Sprite. It is easy to load and display a Sprite3D object:

auto sprite = Sprite3D::create("boss.c3b"); //c3b file, created with the FBX-converter
sprite->setScale(5.f); //sets the object scale in float
sprite->setPosition(Vec2(200,200)); //sets sprite position
scene->addChild(sprite,1); //adds sprite to scene, z-index: 1

This creates and positions a Sprite3D object from .c3b file. Example:

Now, let's rotate the model in a loop. For this we will create an action and run it:

//rotate around the X axis
auto rotation = RotateBy::create(15, Vec3(0, 360, 0));
//our sprite object runs the action
sprite->runAction(RepeatForever::create(rotation));

To set an anchor point on the Sprite or Sprite3D use:

sprite->setAnchorPoint(Point(0.0f,0.0f));

Attaching 3D models to Sprite3D objects.

Recall above that a 3D model is a collection of meshes. You can attach 3D models to other 3D models to create rich effects. An example would be adding a weapon to a character. To do this you need to find the attachment point where the weapon is to be added. For this use the getAttachNode(attachment_point_name) function. And then we just add the new model to the attachment point as a child with addChild(). You can think of this as combining multiple simpler 3D models to create more complex models. For example adding a model to a Sprite3D object:

auto sp = Sprite3D::create("axe.c3b");
sprite->getAttachNode("Bip001 R Hand")->addChild(sp);

Swap 3D Model

When doing 3D development you might want to make dynamic changes to your model. Perhaps due to power-ups, costume changes or visual cues to notify the user about status changes of your model. If your 3D model is comprised from meshes you can access the mesh data using getMeshByIndex() and getMeshByName(). Using these functions it is possible to achieve effects like swapping a weapon or clothing for a character. Let's take a look at an example of a girl wearing a coat:

We can change the coat that the girl is wearing by changing the visibility of the mesh objects we are using. The following example demonstrates how to do this:

auto sprite = Sprite3D::create("ReskinGirl.c3b");

// display the first coat
auto girlTop0 = sprite->getMeshByName("Girl_UpperBody01");
girlTop0->setVisible(true);

auto girlTop1 = sprite->getMeshByName("Girl_UpperBody02");
girlTop1->setVisible(false);

// swap to the second coat
girlTop0->setVisible(false);
girlTop1->setVisible(true);

The results: