rendy-descriptor tries to create a pool of size 0

[kvark]

Reported in https://github.com/gfx-rs/wgpu-rs/issues/149

VALIDATION [VUID-VkDescriptorPoolCreateInfo-poolSizeCount-arraylength (0)] : vkCreateDescriptorPool: parameter pCreateInfo->poolSizeCount must be greater than 0. The Vulkan spec states: poolSizeCount must be greater than 0 (https://www.khronos.org/registry/vulkan/specs/1.1-extensions/html/vkspec.html#VUID-VkDescriptorPoolCreateInfo-poolSizeCount-arraylength) object info: (type: UNKNOWN, hndl: 0)

Way to reproduce:

git clone https://github.com/gfx-rs/wgpu-rs
cd wgpu-rs
cargo run --example hello-triangle

[zakarumych]

Not just pool of size 0, but pool without any sizes. Each size is for different descriptor types. Which means that wgpu tries to allocate descriptor set without any descriptors.

[kvark]

Doesn't Vulkan allow empty descriptor sets and layouts? In this code - https://github.com/gfx-rs/wgpu/issues/240#issue-461599114 , for example the validation layer doesn't complain about the descriptor set layout. Which means, from wgpu perspective this is a valid thing to ask Rendy, and rendy-descriptor should handle this and not try to allocate an empty pool.

[hbina]

Is this bug fixed already? I am not able to reproduce

hbina@hbinalapt:~/git/wgpu-rs$ cargo run --example hello-triangle
    Finished dev [unoptimized + debuginfo] target(s) in 0.34s
     Running `target/debug/examples/hello-triangle`
hbina@hbinalapt:~/git/wgpu-rs$ 

[kvark]

No, we changed the example to not do this any more

[hbina]

So where should I look to fix this bug? The repository is enough.

[kvark]

wgpu has switched to a fork of rendy libraries in https://github.com/gfx-rs/gfx-extras . You can reproduce it by running hello-triangle example in https://github.com/gfx-rs/wgpu-rs/commit/1e3b1a38fe599420f15741114ecd0fcdee8c43f3