WebGPURenderer: Add bloom emissive/selective examples

[sunag]

Related issue: #28903

Description

Live example

[Mugen87]

Good call to make a separate example for this!

A common feature request is selective bloom meaning only certain objects of the scene should be affected by the bloom effect. The setup of the existing example is a bit complicated though: webgl_postprocessing_unreal_bloom_selective

When I understand the new example correctly, emissive could also be used for selective bloom by defining an emissive color for each object that should be affected by bloom, right? Do you think we could port webgl_postprocessing_unreal_bloom_selective to WebGPURenderer by using this approach?

[sunag]

It's possible control the intensity of bloom per object now.

Live example

[sunag]

When I understand the new example correctly, emissive could also be used for selective bloom by defining an emissive color for each object that should be affected by bloom, right? Do you think we could port webgl_postprocessing_unreal_bloom_selective to WebGPURenderer by using this approach?

webgpu_mrt_mask is the approach base that I used for these two examples

[Mugen87]

Great solution! Much better than what we had before with WebGLRenderer 👍.