Q:

Three.js - sprite depths rendering backwards in r70+

It looks like something broke with r70+ regarding z-depth of sprites.
Here is a jsfiddle that works perfect with r69.
Here is the same jsfiddle except using r71.
You can see that now when the scene rotates, the depths of the sprites are not always shown correctly. Half the time they are rotated into view with wrong z-depths.
Is this a bug or is something new I need to add that I missed?
I've tried all variations of common commands below and nothing seems to work all around like it used to.
var shaderMaterial = new THREE.ShaderMaterial({

    ...
    depthTest:      false,
    depthWrite:      false,
    transparent:    true
});

particleSystem.sortParticles = true;

I'm aware of the new renderDepth, but that solution seems to be unrelated and doesn't explain why it would break previous behaviour. We don't need to continually update renderDepths manually for all camera angles now do we?

A:

PointCloud.sortParticles was removed in three.js r70; see this commit.
In your original example (without transparency), you can get your desired behavior by enabling the depth test for your material:
var shaderMaterial = new THREE.ShaderMaterial({

    ...
    depthTest: true
});

In your updated example (with transparency), it's necessary to sort the particles yourself in three.js r70.
Note that three.js still handles z-sorting when rendering THREE.Sprite objects. That could be worth investigating.

