Models Roadmap

[pjcozzi]

Soonish

• glTF schema and spec updates
• When repeating an animation, check for parameter[count -1] === parameter[0].
• Embedded shaders, textures, and buffers.
• Render in and morph to/from Columbus view. Adjust model scale relative to projection?
• Render in and morph to/from 2D.
• Remove computeWorldBoundingSphere?
• Consistently name id and name in Cesium API to match glTF spec.
• Add ById versions of functions like getNode?
• How will users know the names of nodes/meshes/materials/parameters? Through the glTF property or easier to navigate properties?

Later

glTF Features

• Compression
• Cube maps
• Cameras

glTF Extensions

• Collision volumes
• Binary JSON

Animation

• Morphing - #164
• Material animation, including splines with control points of any type.
• Consider skinning with dual quaternions.
• Animation blending, e.g., walk to run cycle. Section 11.6 in Game Engine Architecture
• Bezier spline

Animation Performance

• Only update the joint matrices if the nodes were targeted by an animation that frame, instead of updating the joint matrices for all skinned nodes.
• Don't animation when culled. Will still need the right bounding volume: perhaps we can compute it or the user can provide a maximum radius percentage increase.
• updateNodeHierarchyModelMatrix performance ideas with parent pointers. See @pjcozzi's notes.

Loading Performance

• Fine-grained dependency requests, e.g., compile shader program once required shaders are fetched, not once all shaders are fetched. See functions called from createResources.
• In general, what can be done on a web worker?

Rendering Performance

• Auto instance when multiple nodes have the same mesh. This will require copy-on-write if the material for one instance changes, e.g., because it is no longer an instance.
• Compute tighter bounding sphere than using the bounding box's corner points. Do this as a preprocess in an extra property and fallback to client-side.
• Minimize frustum overlap (SAH-like split) - @bagnell
• Material-aware draw commands, #797 - @bagnell
  • Cull entire model with a single bounding volumes?
• Pack uniforms. Optimize setting uniforms #649
• Coarse front-to-back sort for early-z.
• Investigate DXT-compressing textures in a web worker with Crunch using Emscripten. This could be useful throughout Cesium.
• Optimize 2D with render-to-texture within a given zoom interval for non-animated/skinned models.
• When allowPicking is false, we should still render depth.

Cesium-Specific Features

• Add helpers to ModelNode to, for example, easily change the scale transform and interop with TRS animations.
• Expose glTF animations with higher-level objects than glTF, e.g., cleanly expose time[0] and the duration.
• Expose targetable materials. Extend ModelMesh.
• Support models in KML.
• Reuse texture and vertex buffers when loading multiple models. Probably separate model and instances.
• Attach points. Need access to node's transform (to root) by name. The transform can change over time due to animation, user interaction, etc.
  • Attach vapor trails to the back of a launch vehicle.
  • Attach a sensor to the front of a UAV.
• Pointing. Need semantics for sun, other objects, etc. to control direction and up vectors.
  • Point satellite solar panels to the sun.
  • Point sensor on aircraft to a ground station.
  • Point communication dish to satellite.
  • Point a quad toward the camera, e.g., foliage, explosion, Rudolph's nose, etc. Need to animate when camera moves, not just when time changes.
  • Need to limit degrees of freedom, e.g., one rotation for solar panels and two rotations for communication dish.
• Shadows
• Interop with the Cesium material system?
• Ability to change states. More IE 11 fixes #1843

CZML

• Schedule animations via CZML, i.e., CZML for calling model.activeAnimations.add.
• Drive model pointing.
• Embed glTF as a CZML extension? Package together as zip?

Model caching

• Reference counting the animation cache so it is also automatically deleted.
• Ability to invalidate the whole cache or the cache for one url/cache-key
• Avoid potential ping-ponging by delaying actually removing from the cache when the count reaches zero for several frames/seconds. This may also move all the GL delete functions into the render loop, which would be better for requestAnimationFrame timing (however, perhaps not noticeable).
• Zero out the embedded resources in the glTF to save even more memory?

Viewer

• Drag and drop convert COLLADA to glTF via Rest3D web services?

Ecosystem

• glTF tutorial series
• Make gltfStatistics a separate library

Potential Ideas

• maximumSizeInPixels so the min/max could be the same and used as a billboard
• For performance, render to texture with depth map when pixel size is constant and there are no animation/light changes (billboarding)

Older

b26

General

• Unit tests
• Sandcastle example with sample models
• Tutorial

Animation

• Add offset (in seconds) to ModelAnimation to allow starting an animation "in progress?"
• Skinning - #100

Animation - Cesium Splines - @bagnell

• Change math in splines to use result parameters
• Change splines from AOS to SOA to share time array and for less cache pollution
• Optimize splines for decreasing time
• Spline for piecewise linear interpolation
• Spline for quaternion interpolation with SQUAD

Animation Performance

• Fast slerp - @bagnell
• Optimize Matrix4.fromTranslationQuaternionRotationScale - @bagnell

Rendering Performance

• Preprocess out DeveloperError, Remove DeveloperError in release build #1240 - @bagnell
• Use world-space bounding volume in DrawCommand - @bagnell

Cesium Cleanup

• Rename attributeIndices to attributeLocations throughout.
• Syncup names in UniformDatatype to WebGL.
• Replace enum with constants to avoid conversion: IndexDatatype, TextureWrap, TextureMinificationFilter, TextureMagnificationFilter, and PrimitiveType.

[ViachaslauBohdan]

@pjcozzi Hi
Is it possible to change the color of a separate model nodes in a cesium latest version v1.113 ?