Corrupted rendering with Integrated Intel GPUs + Vulkan + Indirect

[jf908]

Bevy version

0.16

Relevant system information

Reproducible on 2 machines:

1. Windows 10 + Intel i5-6200U

AdapterInfo { name: "Intel(R) HD Graphics 520", vendor: 32902, device: 6422, device_type: IntegratedGpu, driver: "Intel Corporation", driver_info: "Intel driver", backend: Vulkan }

Driver: 30.0.100.9865 (2021-08-20) Up to date

2. Windows 11 + Intel i7-12700H

AdapterInfo { name: "Intel(R) Iris(R) Xe Graphics", vendor: 32902, device: 18086, device_type: IntegratedGpu, driver: "Intel Corporation", driver_info: "101.6790", backend: Vulkan }

Driver: 32.0.101.6790 (2025-05-22) Up to date

Note that this device also has an Nvidia RTX 3070 Ti Laptop GPU but I'm testing the integrated GPU via PowerPreference::LowPower.

What you did

Render one 3D object with transparency and one without. eg. run the transparency_3d example

What went wrong

A random assortment of objects are rendered:

I apologise for using an example where the objects intentionally fade in/out so its not obvious there's a problem. However, the screenshots have been taken at times where all objects are supposed to be drawn. The 2 cubes in this scene always have the same transparency value but in the screenshot you can see that one is rendered while the other isn't.

This bug seems as though it can also appear as flickering objects, incorrect materials per mesh, and random vertex positions.

Additional information

Doesn't happen if you use DirectX 12 or add NoIndirectDrawing to the camera.

[IceSentry]

Can you share a video? Does it happen with just a transparent cube or is this caused by a specific mesh?

[jf908]

Unfortunately I can't share the original model, the transparent object was just not rendered randomly 1/10 frames. Perhaps it was swapping with an invisible material elsewhere in the scene.

However, I have managed to recreate what I think is the same bug in a different form:

Here is a transparent sphere and solid monkey:

Using NoIndirectDrawing (correct):

Default settings (not correct):

There's a 50/50 chance that either the sphere or the monkey is rendered with what looks like a combination of both materials. There's also a really rare chance that the scene is messed up like the vertex indices are wrong but I didn't manage to screenshot it.

assets.zip

I have updated the issue title and description to address the general corruption of the rendering rather than just the transparency being broken.

[GediMini]

Potentially related issue, also on integrated Intel GPU + Vulkan

Rendering 3 transparent objects, a cuboid and two planes, see below. Consistently, only two of these objects were rendered. As I panned the camera, the two closest to the camera appear OK, the third one disappears.

The issue seems to be mitigated if I switch from AlphaMode::Blend to AlphaMode::AlphaToCoverage (I haven't tested other cases). Opaque objects seem to be rendered OK.

    let plane_material = materials.add(StandardMaterial {
        base_color: color,
        alpha_mode: AlphaMode::AlphaToCoverage,
        cull_mode: None,
        ..default()
    });

Was OK on 0.14.0, broken on 0.16.0. But it's possible that something subtle is going on and I'm misidentifying the issue.

Edit: switching the AlphaMode value didn't fix all of the jittery issues, but switching to a DX12 backend seems to have helped.

[jf908]

I figured out that this behaviour also appears on the transparency_3d example, should be much easier to reproduce now, updated the initial issue with more screenshots.

One of the laptops I'm testing on has multiple GPUs so I had to use this to get it to run on the integrated graphics:

        .add_plugins(DefaultPlugins.set(RenderPlugin {
            render_creation: RenderCreation::Automatic(WgpuSettings {
                power_preference: PowerPreference::LowPower,
                ..default()
            }),
            ..default()
        }))

Since its reproducible on another machine with only 1 gpu, I'm fairly confident it's specifically an intel gpu issue, not a low power/multi gpu issue.