1938671 - WebGPU Sponza Demo does not run

Status: NEW

(Core :: Graphics: WebGPU, defect)

Description

[Erich Gubler [:ErichDonGubler] (he/him)]

Steps to reproduce

1. Open the page. Observe that the page loads some controls, but otherwise only renders a black screen.

Comment 1

[Erich Gubler [:ErichDonGubler] (he/him)]

I noticed three distinct problems that were interfering with successful render on our end from the developer console:

1. We're running into a lack of support for automatic type conversion (again) via bug 1829879. Ugh. ETA: After consuming gnikoloff/webgpu-sponza-demo#24, which resolves subsequent items, this is the only blocker I have discovered:

   Uncaptured WebGPU error: Shader module creation failed: Shader validation error
   Encountered one or more errors while creating shader module "Update Lights Shader Module"
   WebGPU compilation info for shader module "Update Lights Shader Module" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Entry point updatePointLights at Compute is invalid
      ┌─ Update Lights Shader Module:94:7
      │
   94 │       (*particle).life = 0;
      │       ^^^^^^^^^^^^^^^^   ^ naga::Expression [25]
      │       │                   
      │       naga::Expression [24]
      │
      = The type of [25] doesn't match the type stored in [24]
   
   
   Uncaptured WebGPU error: ShaderModule with 'Update Lights Shader Module' label is invalid
   Uncaptured WebGPU error: Pipeline constant error in ShaderStages(VERTEX) shader: MSL: MissingValue("ANIMATED_PARTICLES_OFFSET_START")
   Encountered one or more errors while creating shader module "Skybox Material material vertex shader module"
   WebGPU compilation info for shader module "Skybox Material material vertex shader module" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Entry point fragmentMain at Fragment is invalid
       ┌─ Skybox Material material vertex shader module:119:17
       │
   119 │     var color = textureSampleLevel(inTexture, inSampler, cubemapVec, 4); //7.8);
       │                 ^^^^^^^^^^^^^^^^^^ naga::Expression [10]
       │
       = Expression [10] is invalid
       = Sample level (exact) type [9] has an invalid type
   
   
   Uncaptured WebGPU error: Error matching ShaderStages(VERTEX) shader requirements against the pipeline, caused by: ShaderModule with 'Skybox Material material vertex shader module' label is invalid
   Encountered one or more errors while creating shader module "Directional Light Pass Shader Module"
   WebGPU compilation info for shader module "Directional Light Pass Shader Module" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Function [8] 'PBRLighting' is invalid
       ┌─ Directional Light Pass Shader Module:189:3
       │  
   189 │ ╭   fn PBRLighting(
   190 │ │     material: Material,
   191 │ │     instanceId: u32,
   192 │ │     viewSpacePos: vec3f,
       · │
   264 │ │       let irradiance = textureSampleLevel(diffuseIBLTexture, envTexSampler, worldSpaceNorm, 0).rgb;
       │ │                        ^^^^^^^^^^^^^^^^^^ naga::Expression [110]
       · │
   294 │ │ 
   295 │ │     return vec4f(color, opacity);
       │ ╰─────────────────────────────────^ naga::Function [8]
       │  
       = Expression [110] is invalid
       = Sample level (exact) type [109] has an invalid type
   
   
   Uncaptured WebGPU error: Error matching ShaderStages(FRAGMENT) shader requirements against the pipeline, caused by: ShaderModule with 'Directional Light Pass Shader Module' label is invalid
   Encountered one or more errors while creating shader module "Shader Module #17"
   WebGPU compilation info for shader module "Shader Module #17" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Function [10] 'ShadowCalculate' is invalid
       ┌─ Shader Module #17:289:3
       │  
   289 │ ╭   fn ShadowCalculate(
   290 │ │     worldPos: vec3f,
   291 │ │     N: vec3f,
   292 │ │     lightPosition: vec3f,
       · │
   333 │ │     shadow /= 16;
       │ │     ^^^^^^^^^^^^ naga::Expression [79]
   334 │ │ 
   335 │ │     return shadow;
       │ ╰──────────────────^ naga::Function [10]
       │  
       = Expression [79] is invalid
       = Operation Divide can't work with [78] (of type Scalar(Scalar { kind: Float, width: 4 })) and [77] (of type Scalar(Scalar { kind: Sint, width: 4 }))
   
   
   Uncaptured WebGPU error: Error matching ShaderStages(FRAGMENT) shader requirements against the pipeline, caused by: ShaderModule with 'Shader Module #17' label is invalid
   Encountered one or more errors while creating shader module "Point Light Render Pass Fragment Shader"
   WebGPU compilation info for shader module "Point Light Render Pass Fragment Shader" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Function [10] 'ShadowCalculate' is invalid
       ┌─ Point Light Render Pass Fragment Shader:287:3
       │  
   287 │ ╭   fn ShadowCalculate(
   288 │ │     worldPos: vec3f,
   289 │ │     N: vec3f,
   290 │ │     lightPosition: vec3f,
       · │
   331 │ │     shadow /= 16;
       │ │     ^^^^^^^^^^^^ naga::Expression [79]
   332 │ │ 
   333 │ │     return shadow;
       │ ╰──────────────────^ naga::Function [10]
       │  
       = Expression [79] is invalid
       = Operation Divide can't work with [78] (of type Scalar(Scalar { kind: Float, width: 4 })) and [77] (of type Scalar(Scalar { kind: Sint, width: 4 }))
   
   
   Uncaptured WebGPU error: Error matching ShaderStages(FRAGMENT) shader requirements against the pipeline, caused by: ShaderModule with 'Point Light Render Pass Fragment Shader' label is invalid
   Encountered one or more errors while creating shader module "Shader Module #23"
   WebGPU compilation info for shader module "Shader Module #23" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Function [4] 'ComputePosAndReflection' is invalid
       ┌─ Shader Module #23:87:3
       │  
    87 │ ╭   fn ComputePosAndReflection(
    88 │ │     tid: vec2u,
    89 │ │     viewNormal: vec3f,
    90 │ │     projectionMatrix: mat4x4f,
       · │
   106 │ │     samplePosClipSpace.y *= -1;
       │ │     ^^^^^^^^^^^^^^^^^^^^^^^^^^ naga::Expression [39]
       · │
   131 │ │     (*outMaxDistance) = min(*outMaxDistance, select((1 - (*outSamplePosInTexSpace).y) / (*outReflDirInTexSpace).y, -(*outSamplePosInTexSpace).y / (*outReflDirInTexSpace).y, (*outReflDirInTexSpace).y < 0));
   132 │ │     (*outMaxDistance) = min(*outMaxDistance, select((1 - (*outSamplePosInTexSpace).z) / (*outReflDirInTexSpace).z, -(*outSamplePosInTexSpace).z / (*outReflDirInTexSpace).z, (*outReflDirInTexSpace).z < 0));
       │ ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────^ naga::Function [4]
       │  
       = Expression [39] is invalid
       = Operation Multiply can't work with [38] (of type Scalar(Scalar { kind: Float, width: 4 })) and [37] (of type Scalar(Scalar { kind: Sint, width: 4 }))
   
   
   Uncaptured WebGPU error: ShaderModule with 'Shader Module #23' label is invalid
   Encountered one or more errors while creating shader module "Shader Module #25"
   WebGPU compilation info for shader module "Shader Module #25" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Entry point main at Compute is invalid
      ┌─ Shader Module #25:34:13
      │
   34 │     let a = textureSampleLevel(srcTexture, srcSampler, vec2(texCoords.x - 2 * x, texCoords.y + 2 * y), 0).rgb;
      │             ^^^^^^^^^^^^^^^^^^ naga::Expression [41]
      │
      = Expression [41] is invalid
      = Sample level (exact) type [40] has an invalid type
   
   
   Uncaptured WebGPU error: ShaderModule with 'Shader Module #25' label is invalid
   Uncaptured WebGPU error: In a set_pipeline command, caused by: ComputePipeline with 'Update Lights Compute PSO' label is invalid
   Uncaptured WebGPU error: Command encoder is locked by a previously created render/compute pass. Before recording any new commands, the pass must be ended.
   Uncaptured WebGPU error: Command encoder is invalid
   Uncaptured WebGPU error: CommandBuffer with 'Frame Command Encoder' label is invalid
   Encountered one or more errors while creating shader module "Shader Module #31"
   WebGPU compilation info for shader module "Shader Module #31" (1 error(s), 0 warning(s), 0 info)
   
   Shader validation error: Entry point main at Compute is invalid
      ┌─ Shader Module #31:94:23
      │
   94 │         irradiance += textureSampleLevel(inTexture, cubeSampler, sampleVector, 2).rgb * cos(theta) * sin(theta);
      │                       ^^^^^^^^^^^^^^^^^^ naga::Expression [80]
      │
      = Expression [80] is invalid
      = Sample level (exact) type [79] has an invalid type
   
   
   Uncaptured WebGPU error: ShaderModule with 'Shader Module #31' label is invalid
   Uncaptured WebGPU error: In a set_pipeline command, caused by: ComputePipeline with 'Diffuse IBL Compute PSO' label is invalid
   Uncaptured WebGPU error: CommandBuffer with 'Diffuse IBL Command Encoder' label is invalid 
   

2. We're missing @must_use attribute support (see bug 1878314), and shaders from this demo use it. The easy workaround is to simply remove them, but given the helpful diagnostics these attributes are supposed to emit, I don't recommend doing it.

3. ptr<storage, …> usage is rejected by Firefox, where several members are being accessed of the form pointer.member. Switching the syntax to use (*pointer).member seems to work around this. I'm not sure if this is standard or not, and which technology needs to fix something. I don't see supporting examples, but I haven't checked CTS yet. (ETA: This is the pointer_composite_access language extension, which is tracked by bug 1938932.)

Comment 2

[Erich Gubler [:ErichDonGubler] (he/him)]

I opened a PR to track the code I wrote to triage and uncover the issues I wrote earlier: gnikoloff/webgpu-sponza-demo#24

Comment 3

[Jim Blandy :jimb]

Nice analysis!

I think permitting ptr.member was a later addition to the spec. At one point it was not allowed.

Comment 4

[sagudev]

I thin relevant CTS test is here: https://github.com/gpuweb/cts/blob/9873a0fcea54ecb223e1312486dea37618eb5841/src/webgpu/shader/execution/expression/unary/address_of_and_indirection.spec.ts#L121, but it gets skipped because there is no pointer_composite_access wgsl extension in firefox/wgpu. See relevant change in spec: https://github.com/gpuweb/gpuweb/pull/4311.

Comment 5

[Erich Gubler [:ErichDonGubler] (he/him)]

:samson: Just added tracking for the pointer_composite_access language extension via bug 1938932.

Comment 6

[Erich Gubler [:ErichDonGubler] (he/him)]

:jimb: I've updated comment 1 to have the full set of shader validation errors emitted to console for item (1). Hope it helps!

Comment 8

[Erich Gubler [:ErichDonGubler] (he/him)]

@must_use is now usable, now that bug 1878314 has been resolved.

Comment 9

[Erich Gubler [:ErichDonGubler] (he/him)]

Getting the following errors now:

Shader validation error: Function [12] 'FindIntersectionHiZ' is invalid
    ┌─ Shader Module #23:251:3
    │  
251 │ ╭   fn FindIntersectionHiZ(
252 │ │     samplePosInTexSpace: vec3f,
253 │ │     reflDirInTexSpace: vec3f,
254 │ │     maxTraceDistance: f32,
    · │
309 │ │       let thickness = select(0, (ray.z - cellMinZ), level == 0);
    │ │                       ^^^^^^ naga::ir::Expression [108]
    · │
331 │ │     
332 │ │     return intensity;
    │ ╰─────────────────────^ naga::ir::Function [12]
    │  
    = Expression [108] is invalid
    = Expected selection argument types to match, but reject value of type Scalar(Scalar { kind: Sint, width: 4 }) does not match accept value of value Scalar(Scalar { kind: Float, width: 4 })

This is bug 1960453.

Shader validation error: Entry point main at Compute is invalid
   ┌─ Shader Module #25:34:13
   │
34 │     let a = textureSampleLevel(srcTexture, srcSampler, vec2(texCoords.x - 2 * x, texCoords.y + 2 * y), 0).rgb;
   │             ^^^^^^^^^^^^^^^^^^ naga::ir::Expression [41]
   │
   = Expression [41] is invalid
   = Sample level (exact) type [40] has an invalid type

Shader validation error: Entry point main at Compute is invalid
   ┌─ Shader Module #31:94:23
   │
94 │         irradiance += textureSampleLevel(inTexture, cubeSampler, sampleVector, 2).rgb * cos(theta) * sin(theta);
   │                       ^^^^^^^^^^^^^^^^^^ naga::ir::Expression [80]
   │
   = Expression [80] is invalid
   = Sample level (exact) type [79] has an invalid type

This is bug 1952980.

Comment 10

[Erich Gubler [:ErichDonGubler] (he/him)]

I can confirm that the shader compilation issues caused by bug 1952980 are now resolved. Just waiting for bug 1960453, it seems!

Comment 11

[Erich Gubler [:ErichDonGubler] (he/him)]

Running into this error now that bug 1960453 is resolved:

Uncaptured WebGPU error: In a pass parameter, caused by: Attempted to use Texture with 'Depth + Stencil GBuffer Texture' label (mips 0..1 layers 0..1) with conflicting usages. Current usage TextureUses(RESOURCE) and new usage TextureUses(DEPTH_STENCIL_WRITE). TextureUses(DEPTH_STENCIL_WRITE) is an exclusive usage and cannot be used with any other usages within the usage scope (renderpass or compute dispatch).
Uncaptured WebGPU error: Encoder is invalid
Uncaptured WebGPU error: CommandBuffer with 'Frame Command Encoder' label is invalid 

Comment 12

[Teodor Tanasoaia [:teoxoy]]

I think for this to work we need to make the trackers aware of a view's aspect; the demo probably wants to read from one aspect and write to the other in the same pass.