Add an ArUcoScene
=================

An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) class defines a space where [areas of interest description](aoi_description.md) is mapped onto [ArUco markers description](aruco_markers_description.md).

![ArUco scene](../../img/aruco_scene.png)

## Add ArUcoScene to ArUcoCamera JSON configuration file

An [ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera) instance can contains multiples [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene).

Here is an extract from the JSON [ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera) configuration file with a sample where one scene is added:

```json
{
	"name": "My FullHD camera",
	"size": [1920, 1080],
	...
    "scenes": {
        "MyScene" : {
            "aruco_markers_group": {
                "dictionary": "DICT_APRILTAG_16h5",
                "marker_size": 5,
                "places": {
                    "0": {
                        "translation": [2.5, 2.5, 0],
                        "rotation": [0, 0, 0]
                    },
                    "1": {
                        "translation": [0, 25.5, 2],
                        "rotation": [0, 45, 0]
                    },
                    "2": {
                        "translation": [35.5, 0, 3],
                        "rotation": [-45, 0, 0]
                    }
                }
            } 
        }
    }
    ...
}
```

Now, let's understand the meaning of each JSON entry.

### "MyScene"

The name of the [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene). Basically useful for visualisation purpose.

### ArUco markers group

The 3D places of ArUco markers into the scene as defined at [ArUco markers description chapter](aruco_markers_description.md). Thanks to this description, it is possible to estimate the pose of [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) in [ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera) frame.

!!! note

    [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) pose estimation is done when calling the [ArUcoCamera.watch](../../argaze.md/#argaze.ArFeatures.ArCamera.watch) method.

## Add ArLayer to ArUcoScene to load AOI

The [ArLayer](../../argaze.md/#argaze.ArFeatures.ArLayer) class allows to load areas of interest description.

An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) instance can contains multiples [ArLayers](../../argaze.md/#argaze.ArFeatures.ArLayer).

Here is the previous extract where one layer is added to the [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene):

```json
{
    "name": "My FullHD camera",
    "size": [1920, 1080],
    ...
    "scenes": {
        "MyScene" : {
            "aruco_markers_group": {
                ...
            },
            "layers": {
                "MyLayer": {
                    "aoi_scene": {
                        "YellowSquare": [[6.2, -7.275252, 25.246159], [31.2, -7.275252, 25.246159], [6.2, 1.275252, 1.753843], [31.2, 1.275252, 1.753843]],
                        "GrayRectangle": [[2.5, 2.5, -0.5], [37.5, 2.5, -0.5], [2.5, 27.5, -0.5], [37.5, 27.5, -0.5]],
                        "BlueTriangle": [[12.5, 7.5, -0.5], [27.5, 7.5, -0.5], [20, 22.5, -0.5]]
                    }
                }
            } 
        }
    }
    ...
}
```

Now, let's understand the meaning of each JSON entry.

### "MyLayer"

The name of the [ArLayer](../../argaze.md/#argaze.ArFeatures.ArLayer). Basically useful for visualisation purpose.

### AOI Scene

The [AOIScene](../../argaze.md/#argaze.AreaOfInterest.AOIFeatures.AOIScene) defines a set of 3D [AreaOfInterest](../../argaze.md/#argaze.AreaOfInterest.AOIFeatures.AreaOfInterest) registered by name.

## Add ArLayer to ArUcoCamera to project AOI

Here is the previous extract where one layer is added to the [ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera):

```json
{
    "name": "My FullHD camera",
    "size": [1920, 1080],
    ...
    "scenes": {
        "MyScene" : {
            "aruco_markers_group": {
                ...
            },
            "layers": {
                 "MyLayer": {
                    "aoi_scene": {
                        ...
                    }
                } 
            } 
        }
    },
    "layers": {
        "MyLayer": {}
    }
    ...
}
```

Now, let's understand the meaning of each JSON entry.

### "MyLayer"

The name of the [ArLayer](../../argaze.md/#argaze.ArFeatures.ArLayer). Basically useful for visualisation purpose.

!!! warning

    An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layer is projected into [an ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera) layer, **provided they have the same name**.

!!! note

    [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layers are projected into their dedicated [ArUcoCamera](../../argaze.md/#argaze.ArUcoMarkers.ArUcoCamera) layers when calling the [ArUcoCamera.watch](../../argaze.md/#argaze.ArFeatures.ArCamera.watch) method.