Web backend does not support BINDING_INDEXING extension

Error message

Web backend does not support BINDING_INDEXING extension

What it means

Raised when creating a bind group whose entry is a BindingResource::TextureViewArray. Texture view arrays require the bindless/BINDING_INDEXING-style capability that the web backend does not support, so the code panics with this message. Functionally the same limitation as buffer/sampler arrays: one texture view per bind group entry only.

Source

Thrown at wgpu/src/backend/webgpu.rs:2329

                crate::BindingResource::BufferArray(..) => {
                    panic!("Web backend does not support arrays of buffers")
                }
                crate::BindingResource::Sampler(sampler) => {
                    let sampler = &sampler.inner.as_webgpu().inner;
                    webgpu_sys::GpuBindGroupEntry::new(binding.binding, sampler)
                }
                crate::BindingResource::SamplerArray(..) => {
                    panic!("Web backend does not support arrays of samplers")
                }
                crate::BindingResource::TextureView(texture_view) => {
                    let texture_view = &texture_view.inner.as_webgpu().inner;
                    webgpu_sys::GpuBindGroupEntry::new_with_gpu_texture_view(
                        binding.binding,
                        texture_view,
                    )
                }
                crate::BindingResource::TextureViewArray(..) => {
                    panic!("Web backend does not support BINDING_INDEXING extension")
                }
                crate::BindingResource::AccelerationStructure(_) => {
                    unimplemented!("Raytracing not implemented for web")
                }
                crate::BindingResource::AccelerationStructureArray(_) => {
                    unimplemented!("Raytracing not implemented for web")
                }
                crate::BindingResource::ExternalTexture(external_texture) => {
                    let external_texture = &external_texture.inner.as_webgpu().inner;
                    webgpu_sys::GpuBindGroupEntry::new_with_gpu_external_texture(
                        binding.binding,
                        external_texture,
                    )
                }
            })
            .collect::<Vec<webgpu_sys::GpuBindGroupEntry>>();

        let bgl = &desc.layout.inner.as_webgpu().inner;

View on GitHub (pinned to 3e11ff59bf)

Solutions

Bind each texture view as a separate BindGroupEntry with distinct binding indices.
Use a texture 2D array image (texture_2d_array) with a single view instead of an array of separate textures.
Restrict TextureViewArray usage to native backends via a backend check and alternate layout on web.

Example fix

// before
entries.push(wgpu::BindGroupEntry { binding: 0, resource: wgpu::BindingResource::TextureViewArray(&views) });
// after
for (i, v) in views.iter().enumerate() {
    entries.push(wgpu::BindGroupEntry { binding: i as u32, resource: wgpu::BindingResource::TextureView(v) });
}

Defensive patterns

Strategy: validation

Validate before calling

for e in &entries {
    assert!(!matches!(e.resource, wgpu::BindingResource::TextureViewArray(_)), "TextureViewArray unsupported on web backend");
}

Type guard

fn has_no_view_array(entries: &[wgpu::BindGroupEntry]) -> bool {
    entries.iter().all(|e| !matches!(e.resource, wgpu::BindingResource::TextureViewArray(_)))
}

Prevention

Prefer texture_2d_array with a single view over arrays of separate views.
Use per-entry bindings when the texture count is small.
Gate bindless-style code behind a native-only feature flag.

When it happens

Trigger: Calling device.create_bind_group with a BindGroupEntry whose resource is BindingResource::TextureViewArray(&[...]) on the web backend, for a layout entry declaring an array of sampled textures.

Common situations: Bindless texture atlases / texture arrays indexed in shaders, written for native; material systems with dynamic texture indices; porting desktop renderers to wasm32-web.

Related errors

AI-assisted analysis of gfx-rs/wgpu@3e11ff59bf (2026-09-03). Data as JSON: /api/errors/df5d40bc1251207b. Report an issue: GitHub.