Multiple Viewports

Allow for multiple viewports/camera views in a single canvas.

• One SceneManager containing multiple Scenes
  • SceneManager contains all non-view dependent primitives.
    • Primitives updated once and rendered in each viewport
    • Option on each primitive to hide for any number of viewports
  • Each Scene contains a copy of view dependent primitives.
    • Includes Globe
      • All globes search terrain geometry and texture cache before requests
      • All globes have the same terrain and imagery providers?
      • Allow globes to have different terrain and imagery providers?
      • Allow for different celestial bodies? (not implemented)
    • Includes 3D Tilesets
      • All tilesets search a geometry and texture cache before requests
      • Allow different styling?
        • Each tileset will have its own style and batch table
    • Any other primitive where each vertex needs to be multiplied by a view dependent transform on the CPU.
• One Scene with a list of Viewports that contain a camera and viewport rectangle.
  • Non-view dependent primitives updated and rendered in each viewport.
  • View dependent primitives can keep a command list per-viewport after updating for each camera
    • Can not have different terrain or imagery provider
    • Can not style 3D Tilesets per viewport.

The first option is more flexible but more complex. The second option is simpler but has a couple of constraints.

• Z-order the viewports. Model after PrimitiveCollection.
• ScreenSpaceCameraController needs to know which viewport the input originated in.
• Viewport positioning.
  • Absolute values. App responsible for resizes
  • Custom positioning implementation
  • Position with CSS and hidden divs. Potentially expensive.
• Screen space passes for each viewport and for the final framebuffer.
• Allow the same primitive to have a different material in each viewport? (probably not)

[DoubleYellowEgg]

What is the current progress? Is there no follow-up to this question?

[OmarShehata]

Requested again on the forum: https://groups.google.com/d/msg/cesium-dev/SUqz4UGrSMA/F-l1ZuRTBwAJ

There is a common need for monitoring system: Users want to see more then one screen at the same time and each screen show a map in 3D or 2D and display diffrent images. For example,the first shows satellite images in 3D ,the second shows road map in 2D, … They expect the multiple screens show the same data and synchronized. The data maybe come from server or mouse ploting.