Cesium and three.js

[m-schuetz]

Hi,

I hope it's fine if I open an issue here while I'm working on a demo with Cesium and three.js combined. ( related to #648 )
You can find a video of a working example here: https://www.youtube.com/watch?v=bnn39nNbDfA
I'll upload the whole thing once I've cleaned some stuff up.

To make this possible, at least for opaque objects, we need to be able to inject three.js render code into the cesium render pipeline. In the example given in the video, I've added a callback during the globe pass in Scene.js

// Cesium - Scene.js

us.updatePass(Pass.GLOBE);
var commands = frustumCommands.commands[Pass.GLOBE];
var length = frustumCommands.indices[Pass.GLOBE];
for (j = 0; j < length; ++j) {
    executeCommand(commands[j], scene, context, passState);
}

renderThreeJS({
	numFrustums: numFrustums,
	i: i,
	frustumCommands: frustumCommands,
	scene: scene,
	camera: camera,
	frustum: frustum,
	passState: passState
});

Do you have any suggestion/preference on how you'd allow developers to hook into the rendering pipeline?
Not sure how event handling is done in cesium. I'd usually do something like this:

// first, render globe
us.updatePass(Pass.GLOBE);
var commands = frustumCommands.commands[Pass.GLOBE];
var length = frustumCommands.indices[Pass.GLOBE];
for (j = 0; j < length; ++j) {
    executeCommand(commands[j], scene, context, passState);
}

// then, notify all globe_pass listeners
for(let listener of listeners["globe_pass"]){
	listener(numFrustums, frustum, camera);
}

Threejs developers could then add their render code like this:

cesium.addEventListener("globe_pass", (numFrustums, frustum, camera) => {
	// threejs render code here
	// e.g. copy view and projection matrices, as well as near and far from cesium
	// then call threeRenderer.render(threeScene, threeCamera);
})

• We'd probably also need to let cesium know of the bounds of the three.js objects.
• Another callback before the frustum loop is probably also usefull/necessary to give threejs developers the chance to cull and arange the scene for each individual frustum range.

[ggetz]

Hi @m-schuetz !

Thanks for asking, please post discussions over at the Cesium Forum. There are members of the community and developers from the team who answer these kinds of questions there. Additionally, Cesium's a big project, so we use GitHub for feature requests and bug tracking exclusively.

I've gone ahead and opened a new forum thread for this here, and I'm going to close this issue.

Thanks!

[cesium-concierge]

Congratulations on closing the issue! I found these Cesium forum links in the comments above:

https://groups.google.com/forum/#!topic/cesium-dev/GX7xLXrPDsE

If this issue affects any of these threads, please post a comment like the following:

The issue at #6094 has just been closed and may resolve your issue. Look for the change in the next stable release of Cesium or get it now in the master branch on GitHub https://github.com/AnalyticalGraphicsInc/cesium.

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