WebGPURenderer: Detect needsBindGroupRefresh more properly

[takahirox]

This PR lets WebGPURenderer detect needsBindGroupRefresh more properly.

Problem this PR fixes

Renderer seems to have overlooked a case where texture is shared in multiple materials. Currently it determines whether bind group refresh is necessary or not just with comparing texture version and GPU texture version. But it doesn't work correctly if texture is shared in multiple materials. The second or later materials can't detect needsBindGroupRefresh because when they check the GPU texture version it has been already updated by the first material.

Solution

An easy solution would be comparing bind group's GPU texture with the one in texture property managed by WebGPUTextures. Refer to the code for detail.

Without this change. (An example many materials use the same texture.)

With this change.

[Mugen87]

Good find! It seems we need a combination of both approaches. I'm working with render targets right now and this change won't work if a render target's texture is used as a texture. The texture object also requires a bind to the respective group. I'll merge and clean up!

[Mugen87]

b166f40