# Usage

There are two ways to use the library:

- Automatic initialization: Create some div elements on your site, and call a function that automatically initalizes all the viewers. This is the easiest way to use the library, but provides less flexibility.
- Initialization from code: Needs a bit more typing, but it's more flexible than the previous one.

## External library handling

Some of the importers are implemented using external libraries. These are found in the libs folder of the package. To make these libraries available, you have to tell the engine where to find them. The location of the external libraries can be set with the SetExternalLibLocation function. Make sure to call it before any other engine calls.

## Automatic initialization

Create some elements anywhere on your page with the class name `online-3d-viewer`. You can create multiple elements with different parameters.

    <div class="online_3d_viewer"
        style="width: 800px; height: 600px;"
        model="model.obj, model.mtl">
    </div>

You can specify several attributes:

- model: Relative path to model files separated by comma.
- camera: Camera parameters (eye, center, up). 9 comma separated number values.
- defaultcolor: Default color for surfaces with no material. 3 comma separated number values for r, g, b.
- backgroundcolor: Canvas background color. 3 comma separated number values for r, g, b or four comma separated number values for r, g, b, a.
- edgesettings: Edge display settings. 5 comma separated values for 'on'/'off', r, g, b, threshold angle.
- environmentmap: Comma separated list of six images forming a texture box.
- environmentmapbg: Boolean ("true" or "false") to set the environment map as background.

After placing the elements, call the Init3DViewerElements function to initalize all the viewers. It must be called after the document is loaded.

    window.addEventListener ('load', () => {
        // tell the engine where to find the libs folder
        OV.SetExternalLibLocation ('libs');
        // init all viewers on the page
        OV.Init3DViewerElements ();
    });

## Initialization from code

You can also initalize the engine from code. In this case you can provide all the parameters as a JavaScript object. See the EmbeddedViewer documentation for more details.

    window.addEventListener ('load', () => {
        // set the location of the external libraries
        OV.SetExternalLibLocation ('../libs');

        // get the parent element of the viewer
        let parentDiv = document.getElementById ('viewer');

        // initialize the viewer with the parent element and some parameters
        let viewer = new OV.EmbeddedViewer (parentDiv, {
            camera : new OV.Camera (
                new OV.Coord3D (-1.5, 2.0, 3.0),
                new OV.Coord3D (0.0, 0.0, 0.0),
                new OV.Coord3D (0.0, 1.0, 0.0),
                45.0
            ),
            backgroundColor : new OV.RGBAColor (255, 255, 255, 255),
            defaultColor : new OV.RGBColor (200, 200, 200),
            edgeSettings : new OV.EdgeSettings (false, new OV.RGBColor (0, 0, 0), 1),
            environmentSettings : new OV.EnvironmentSettings (
                [
                    'assets/envmaps/fishermans_bastion/posx.jpg',
                    'assets/envmaps/fishermans_bastion/negx.jpg',
                    'assets/envmaps/fishermans_bastion/posy.jpg',
                    'assets/envmaps/fishermans_bastion/negy.jpg',
                    'assets/envmaps/fishermans_bastion/posz.jpg',
                    'assets/envmaps/fishermans_bastion/negz.jpg'
                ],
                false
            )
        });

        // load a model providing model urls
        viewer.LoadModelFromUrlList ([
            'model.obj',
            'model.mtl'
        ]);
    });