Video Streams on Models

The ancillary file allows for your COLLADA models to be edited with any 3D modeling application using placeholder images for textures. When the model is loaded into Insight3D and the ancillary file is present, the references to the placeholder images in the ancillary file are mapped to videos within Insight3D. When the COLLADA model has an ancillary file associated with it, it can be loaded and used like any standard model in Insight3D, as seen below. The actual COLLADA model is never modified.

CentralBody earth = CentralBodiesFacet.GetFromContext().Earth;

ModelPrimitive model = new ModelPrimitive(new Uri(baseUri, "hellfireflame.dae"));
model.SetPositionCartographic(earth, new Cartographic(Trig.DegreesToRadians(49.88),
                                                      Trig.DegreesToRadians(-77.25),
                                                      5000.0));
model.Scale = 100.0;
SceneManager.Primitives.Add(model);

Note
Currently, RasterStream support for COLLADA model textures is provided through the VideoStream interface, which is a derived class. In the future, programmatic manipulation of model textures and the use of RasterStream classes in the ancillary file will be supported.

The ancillary file should exist in the same directory as the COLLADA model, and have the same name as the COLLADA dae file, but with the .dae file extension replaced by .anc. Below, the ancillary file format is shown via the hellfireflame.anc ancillary file, included in the HowTo example, corresponding to the hellfireflame.dae COLLADA model:

<ancillary_model_data version = "1.0">
    <video_textures>
        <video_texture image_id = "smoketex_tga" init_from = "smoke.avi" video_loop="true" video_framerate="60" />
        <video_texture image_id = "flametex_tga" init_from = "flame.mov" video_loop="true" video_framerate="60" />
    </video_textures> 
</ancillary_model_data>

The video_textures section of the ancillary file contains video_texture elements for each image that will be replaced within the COLLADA model, and relevant attributes to associate the image with a video. If we examine the library_images section of the hellfireflame.dae COLLADA model, we see that each video_texture element's image_id attribute in the ancillary file maps to an image element id attribute in the COLLADA model's dae file:

<library_images>
  <image id="flametex_tga">
    <init_from>flametex.tga</init_from>
  </image>
  <image id="flamealpha_tga">
    <init_from>flamealpha.tga</init_from>
  </image>
  <image id="smokealpha_tga">
    <init_from>smokealpha.tga</init_from>
  </image>
  <image id="smoketex_tga">
    <init_from>smoketex.tga</init_from>
  </image>
</library_images>

Individual frames of the smoke.avi and flame.mov videos that are referenced by the ancillary file. Each placeholder image's alpha mask is shown below each frame of the replacement video.

When Insight3D's COLLADA loader encounters a texture containing an image that is mapped to a video in the ancillary file, the video is loaded as a RasterStream in the image's place. The video textures also support common COLLADA texturing techniques that typically apply to static images, such as applying alpha masks with a texture sampler through the transparent attribute of the texture. When such a case is encountered, FilteringRasterStream is used to filter each frame of the video to apply the same effect that a static image would have applied. The ancillary file also has support for applying other common filters to the video, to achieve a variety of effects.