Depth API Applications

Occlsuion Effect

Occlusion is a key application of depth APIs, crucial for creating immersive AR experiences. When virtual objects correctly appear behind real-world objects, the scene becomes more realistic. For example, placing a virtual character behind a physical object requires accurate depth information to render proper occlusion.

Unity Implementation

Core Components

ARFoundation provides the AROcclusionManager component. Attach this script to the AR Camera under AR Session Origin to enable virtual-real occlusion (ensure Depth Mode is not set to disabled).

Script Example

using UnityEngine.XR.ARFoundation;

public class DepthOcclusionController : MonoBehaviour
{
    private AROcclusionManager occlusionManager;

    void Start()
    {
        occlusionManager = GetComponent<AROcclusionManager>();
        occlusionManager.requestedEnvironmentDepthMode = EnvironmentDepthMode.Medium;
    }
}

Native Android Development

Core Approach

1. Obtain depth maps and camera frames
2. Process depth data in shaders
3. Use specialized materials for rendering

Filament Material Example

material {
    name : depth_occlusion,
    shadingModel : unlit,
    parameters : [
        { type : samplerExternal, name : cameraTex },
        { type : sampler2d, name : depthTex },
        { type : float4x4, name : uvMatrix }
    ]
}

fragment {
    void material(inout MaterialInputs mat) {
        vec2 depthData = texture(matParams_depthTex, getUV0()).xy;
        float depth = dot(depthData, vec2(255.0, 256.0 * 255.0));
        // Depth processing logic
    }
}

Scene Component Usage

public class ARSceneActivity extends AppCompatActivity {
    private ARSceneLayout arLayout;

    @Override
    protected void onCreate(Bundle state) {
        super.onCreate(state);
        setContentView(R.layout.ar_layout);
        
        arLayout = findViewById(R.id.ar_view);
        arLayout.getSceneView().getCameraStream()
            .setDepthOcclusionMode(DepthOcclusionMode.ENABLED);
    }
}

Model Rendering

private void loadModel(Context ctx, Node root) {
    ModelRenderable.builder()
        .setSource(ctx, Uri.parse("model.glb"))
        .build()
        .thenAccept(model -> {
            Node modelNode = new Node();
            modelNode.setRenderable(model);
            modelNode.setParent(root);
        });
}