Example do not work, out of the box

[Rusty-Weasel]

First of all, thanks for doing this, egui with vulkan could be a nice thing.

Just tried if it work out of the box, but something wrong

any idea?

[MatchaChoco010]

First of all, thanks for trying the example so quickly!

Please make sure that you are using the latest version of Vulkan SDK in your environment and that you have installed it correctly.

In the example, I use a validation layer called VK_LAYER_KHRONOS_validation, which basically exists in Vulkan.

If the Vulkan SDK is not too old and it does not work, you should check if the installation is done correctly.
Is %VULKAN_SDK% in your PATH set correctly?

[Rusty-Weasel]

Okay tested it, just downloaded latest tar ball and extract to folder + set the following envs (just as test by hand):

envs:

• export VULKAN_SDK=/PATH/TO/vulkansdk/1.3.268.0/x86_64/
• export VK_LAYER_PATH=$VULKAN_SDK/etc/vulkan/explicit_layer.d
• export LD_LIBRARY_PATH=$VULKAN_SDK/lib:$LD_LIBRARY_PATH

Examples:

• egui_ash_simple = works

• egui_ash_vulkan = fail by another error (try to look later at it)
• images = works
• multi_viewports = fail by another error (try to look later at it)
• native_image = works
• scene_view = fail by another error (try to look later at it)
• tiles = fail by another error (try to look later at it)

the other error is mostly the same:
thread 'main' panicked at /.cargo/registry/src/index.crates.io-6f17d22bba15001f/bytemuck-1.14.0/src/internal.rs:32:3:
cast_slice>TargetAlignmentGreaterAndInputNotAligned

so far to the moment :-)

[MatchaChoco010]

I am using bytemuck in examples to convert the shader spv from &[u8] to &[u32].
https://github.com/MatchaChoco010/egui-ash/blob/main/examples/egui_ash_vulkan/renderer.rs#L469-L478

This conversion should not fail because spv should be aligned by 4 bytes, but it appears that the conversion to &[u32] fails because the input spv &[u8] is not aligned to a length that is a multiple of 4.

Are /examples/egui_ash_vulkan/shaders/spv/vert.spv and /examples/egui_ash_vulkan/shaders/spv/frag.spv in multiple of 4 byte size?
They should be 1528bytes and 860bytes respectively.
If these bytes are wrong, the git clone of spv is probably not working.

[Rusty-Weasel]

yes they are

[MatchaChoco010]

Thanks for the confirmation!
Hmmm, why isn't it working?

The only two places in example egui_ash_vulkan that use bytemuck are in the shader loading.

I think the problem is that either include_bytes! is not reading bytes correctly, or there is something wrong with bytemuck::cast_slice...

For example, what would happen to assert if you edited L469-L488 as follows and ran it?
https://github.com/MatchaChoco010/egui-ash/blob/main/examples/egui_ash_vulkan/renderer.rs#L469-L488

let vertex_shader_module = {
    let bytes: &[u8] = include_bytes!("./shaders/spv/vert.spv");
    assert!(bytes.len() % 4 == 0);
    let words: &[u32] = bytemuck::cast_slice(bytes);
    let shader_module_create_info = vk::ShaderModuleCreateInfo::builder().code(words);
    unsafe {
        device
            .create_shader_module(&shader_module_create_info, None)
            .expect("Failed to create shader module")
    }
};
let fragment_shader_module = {
    let bytes: &[u8] = include_bytes!("./shaders/spv/frag.spv");
    assert!(bytes.len() % 4 == 0);
    let words: &[u32] = bytemuck::cast_slice(bytes);
    let shader_module_create_info = vk::ShaderModuleCreateInfo::builder().code(words);
    unsafe {
        device
            .create_shader_module(&shader_module_create_info, None)
            .expect("Failed to create shader module")
    }
};

If assert fails, then something is wrong with include_bytes.
Otherwise, there is something wrong with the cast_slice of bytemuck...

[Rusty-Weasel]

tested -> same as before

[MatchaChoco010]

Okay, I looked it up, and it seems that alignment was a different concept than length.
cast_slice will fail if the address of the first byte in the array is not divisible by 4.

I made a code to try to cast to an array of &[u32] normally without using bytemuck.
Could you try the fix-shader-import branch?
https://github.com/MatchaChoco010/egui-ash/tree/fix-shader-import

[Rusty-Weasel]

[MatchaChoco010]

The image appears to use the main branch？
Could you try fix-shader-import instead of the main branch?

[tyrypyrking]

I had the same issue, and the branch fixed it for me in "tiles" example.
P.S. thank you for this amazing repo, it's exactly what I was looking for.

[Rusty-Weasel]

The image appears to use the main branch？ Could you try fix-shader-import instead of the main branch?

no, it is a seperate clone directly from fix-shade-import branch

[MatchaChoco010]

Hmm, the fix-shader-import branch should not be using cast_slice in bytemuck directly.
Is something in the dependent library causing an error with the cast_slice it uses internally?

@GoWeasel If you don't mind, could you try showing backtrace with RUST_BACKTRACE=1?

[MatchaChoco010]

Today I published 0.2.0 with some fixes and some API changes.
It also includes the contents of the fix-shader-import branch.

If you want, you can try the latest on the main branch and show me the backtrace with RUST_BACKTRACE=1.