Objects

In this section we define the objects in the game and what they will look like when being rendered.

In the game Sokoban we control a player avatar which moves around and pushes boxes into holes, there are walls that we cannot push and we cannot pass.

This means we have 4 objects in our simple Sokoban game. So we need to define them!

Step 1 - Avatar object

Each object we have to give a unique name to. That unique name can then be used to reference that object in other parts of the GDY configuration. In for the avatar object we will call it avatar unsurprisingly.

We’re going to use this image:

Objects:

 - Name: avatar
   Z: 2
   MapCharacter: A
   Observers:
     Sprite2D:
       Image: images/gvgai/oryx/knight1.png

MapCharacter defines the character we will use to describe initial positions in the levels defined in the Environment section of the GDY file.

Z allows us to define that objects can occupy the same location in the grid, as long as they have different Z indexes. It also defines the rendering order when rendering the game. Higher Z-indexes mean the objects will be rendered on top.

The Observers block defines how each observer type will render this particular object. We are defining a Sprite2D observer here so we need to supply an image to it.

Step 2 - Wall Objects

Wall objects are slightly more complicated because when they are rendered they actually use 15 different images, for example corner peices, T-peices etc….

lets look at the object definition for walls!

- Name: wall
  MapCharacter: w
  Observers:
    Sprite2D:
      TilingMode: WALL_16
      Image:
        - images/gvgai/oryx/wall3_0.png
        - images/gvgai/oryx/wall3_1.png
        - images/gvgai/oryx/wall3_2.png
        - images/gvgai/oryx/wall3_3.png
        - images/gvgai/oryx/wall3_4.png
        - images/gvgai/oryx/wall3_5.png
        - images/gvgai/oryx/wall3_6.png
        - images/gvgai/oryx/wall3_7.png
        - images/gvgai/oryx/wall3_8.png
        - images/gvgai/oryx/wall3_9.png
        - images/gvgai/oryx/wall3_10.png
        - images/gvgai/oryx/wall3_11.png
        - images/gvgai/oryx/wall3_12.png
        - images/gvgai/oryx/wall3_13.png
        - images/gvgai/oryx/wall3_14.png
        - images/gvgai/oryx/wall3_15.png

Here we define the Name and the MapCharacter like we did when the avatar was defined. We dont need a Z index because nothing interacts with the wall objects.

In the Sprite2D Object there is now a TilingMode object which can either be WALL_2, or WALL_16. These tiling modes use 2 or 16 images respectively to render the walls in the game environment. The order of the walls is important to render the walls correctly.

Step 3 - Boxes and holes

Boxes and holes are very similar to avatar objects. The only difference is that hole objects have a different Z value which allows the avatar object to move on top of them.

box:

hole:

- Name: box
  Z: 2
  MapCharacter: b
  Observers:
    Sprite2D:
      Image: images/gvgai/newset/block1.png

- Name: hole
  Z: 1
  MapCharacter: h
  Observers:
    Sprite2D:
      Image: images/gvgai/oryx/cspell4.png

Putting it all together

Thats it! We’ve defined our objects and some properties about how they will look in the game.

The completed Object section of our GDY file looks like this:

Objects:
 - Name: box
   Z: 2
   MapCharacter: b
   Observers:
     Sprite2D:
       Image: images/gvgai/newset/block1.png

 - Name: wall
   MapCharacter: w
   Observers:
     Sprite2D:
       TilingMode: WALL_16
       Image:
         - images/gvgai/oryx/wall3_0.png
         - images/gvgai/oryx/wall3_1.png
         - images/gvgai/oryx/wall3_2.png
         - images/gvgai/oryx/wall3_3.png
         - images/gvgai/oryx/wall3_4.png
         - images/gvgai/oryx/wall3_5.png
         - images/gvgai/oryx/wall3_6.png
         - images/gvgai/oryx/wall3_7.png
         - images/gvgai/oryx/wall3_8.png
         - images/gvgai/oryx/wall3_9.png
         - images/gvgai/oryx/wall3_10.png
         - images/gvgai/oryx/wall3_11.png
         - images/gvgai/oryx/wall3_12.png
         - images/gvgai/oryx/wall3_13.png
         - images/gvgai/oryx/wall3_14.png
         - images/gvgai/oryx/wall3_15.png

 - Name: hole
   Z: 1
   MapCharacter: h
   Observers:
     Sprite2D:
       Image: images/gvgai/oryx/cspell4.png

 - Name: avatar
   Z: 2
   MapCharacter: A
   Observers:
     Sprite2D:
       Image: images/gvgai/oryx/knight1.png