libGDX 3D rendering

Question

I'm currently working on a FPS 3D game using libGDX. I aim to have maze-like levels (like the original Doom and Duke Nukem 3D) so I'm making a level editor with a top-down view and lets you stretch lines (which represent walls) and create sectors. I read that libGDX Models aren't efficient if you plan to have lots of them (I believe that a level could have hundreds of lines). My question: is there an alternative to that? I checked Decals but unfortunately they are not affected by an Environment light. Does anybody have any idea how to improve performance to handle these amount of walls? Should I use BSP-Trees in order to render the walls? Thanks

Answer 1

You may look into https://github.com/libgdx/libgdx/wiki/ModelBuilder%2C-MeshBuilder-and-MeshPartBuilder .

You can construct your level walls using a single model with more than one mesh parts.

Here is some sample code:

ModelBuilder worldBuilder = new ModelBuilder();
MeshPartBuilder meshBuilder;
Vector3 corner00 = new Vector3(),
    corner10 = new Vector3(),
    corner11 = new Vector3(),
    corner01 = new Vector3(),
    normal = new Vector3();
modelBuilder.begin();

meshBuilder = worldBuilder.part("room1", GL20.GL_TRIANGLES, Usage.Position | Usage.Normal, new Material());
meshBuilder.rect(corner00.set(-10, -10, 0), //room 1, wall 1
                 corner10.set( 10, -10, 0),
                 corner11.set( 10,  10, 0),
                 corner01.set(-10,  10, 0), normal.set(0, 0, 1));
meshBuilder.rect(corner00.set(-10, -10, 10), //room 1, wall 2
                 corner10.set( 10, -10, 10),
                 corner11.set( 10,  10, 10),
                 corner01.set(-10,  10, 10), normal.set(0, 0, -1));

Node node = modelBuilder.node();
node.translation.set(100,0,0); // next room far away
meshBuilder = worldBuilder.part("room2", GL20.GL_TRIANGLES, Usage.Position | Usage.Normal, new Material());
meshBuilder.rect(corner00.set(-10, -10, 0), //room 2, wall 1
                 corner10.set( 10, -10, 0),
                 corner11.set( 10,  10, 0),
                 corner01.set(-10,  10, 0), normal.set(0, 0, 1));
meshBuilder.rect(corner00.set(-10, -10, 10), //room 2, wall 2
                 corner10.set( 10, -10, 10),
                 corner11.set( 10,  10, 10),
                 corner01.set(-10,  10, 10), normal.set(0, 0, -1));

Model worldModel = worldBuilder.end();

This way you can use meshBuilder in room localCoordinates, and use the nodes to control room positioning.

You can also disable node by node later on, if you want to do BSP optimization and only draw adjacent rooms.