1954080 - [meta] WebGPU: Project Prismatic doesn't work as it should

Status: NEW

(Core :: Graphics: WebGPU, defect)

Description

[Erich Gubler [:ErichDonGubler]]

Extracted from a report by Jukka Jylänki in bug 1912550, comment 8:

---

A Unity games company Stratton Studios has been developing a really impressive looking Unity WebGPU game, that can be visited at https://play.projectprismatic.com/

Runs really great on Chrome, and attempted today to see how it would run on Firefox Nightly. That leads to this deterministic occurring crash at startup:

https://crash-stats.mozilla.org/report/index/b83b17cd-a75c-49bb-b814-e226c0250314#tab-details

STR:

Visit https://play.projectprismatic.com/
Wait for a while for the game to load. (that will take a minute or two) There is an intro video that plays while the game is loading.
Once the game has loaded, the tab will show the "Gah. Your tab just crashed." crash dialog.

E.g. another crash dump: https://crash-stats.mozilla.org/report/index/d6550fc1-4d57-4bba-8182-8e34b0250314

Comment 1

[Erich Gubler [:ErichDonGubler]]

On macOS, I also get these console log warnings:

Uncaptured WebGPU error: Internal error in ShaderStages(VERTEX) shader: Metal: program_source:70:19: warning: unused variable 'u_xlat_precise_vec4_' [-Wunused-variable]
    metal::float4 u_xlat_precise_vec4_ = {};
                  ^
program_source:71:17: warning: unused variable 'u_xlat_precise_ivec4_' [-Wunused-variable]
    metal::int4 u_xlat_precise_ivec4_ = {};
                ^
program_source:72:18: warning: unused variable 'u_xlat_precise_bvec4_' [-Wunused-variable]
    metal::bool4 u_xlat_precise_bvec4_ = {};
             
Uncaptured WebGPU error: Internal error in ShaderStages(VERTEX) shader: Metal: program_source:113:19: warning: unused variable 'u_xlat_precise_vec4_' [-Wunused-variable]
    metal::float4 u_xlat_precise_vec4_ = {};
                  ^
program_source:114:17: warning: unused variable 'u_xlat_precise_ivec4_' [-Wunused-variable]
    metal::int4 u_xlat_precise_ivec4_ = {};
                ^
program_source:115:18: warning: unused variable 'u_xlat_precise_bvec4_' [-Wunused-variable]
    metal::bool4 u_xlat_precise_bvec4_ = {};
          
Uncaptured WebGPU error: Internal error in ShaderStages(VERTEX) shader: Metal: program_source:49:19: warning: unused variable 'u_xlat_precise_vec4_' [-Wunused-variable]
    metal::float4 u_xlat_precise_vec4_ = {};
                  ^
program_source:50:17: warning: unused variable 'u_xlat_precise_ivec4_' [-Wunused-variable]
    metal::int4 u_xlat_precise_ivec4_ = {};
                ^
program_source:51:18: warning: unused variable 'u_xlat_precise_bvec4_' [-Wunused-variable]
    metal::bool4 u_xlat_precise_bvec4_ = {};

Comment 2

[Andy Leiserson]

The failure messages are truncated (which reminds me that I intended to file an issue for this -- now filed as bug 1960041), so those warnings aren't the actual problem. The actual problem is wgpu#7410 Vertex-pulling transform generates invalid metal code in certain cases, fixed in wgpu#7458 [naga msl-out] Fix truncation of pulled vertices, and I believe that was in the wgpu update that just landed. I hadn't previously linked that fix to this bug, but it was linked to the unity demos bug.

Comment 3

[Andy Leiserson]

No longer a crash after fixing bug 1878804.