Per-object uniform data

[cloudhead]

I may be misunderstanding the API, but it doesn't seem like it's possible to have uniform data (eg. transformations) per object/draw call. I'm guessing this can be done if offsets were passed in to RenderPass::set_bind_group:

            pass.raw.bind_graphics_descriptor_sets(
                &&pipeline_layout_guard[pipeline_layout_id].raw,
                index as usize,
                bind_groups,
                &[], // <--------- here
            );

or if there was access to push constants.

Is there another way to have per-draw uniform data?

I'm refering to this for vulkan: https://github.com/nvpro-samples/gl_vk_threaded_cadscene/blob/master/doc/vulkan_uniforms.md

[kvark]

@cloudhead the group has not yet accepted any push constants semantics. In short, it wasn't clear how to best expose them, and in all cases we've seen using push constants wasn't required to get the job done. One workaround is to use the dynamic offsets like you mentioned. The draft spec does have them: https://github.com/gpuweb/gpuweb/blob/15dadf3f218f1c51ff31ce1976653a99189b41d1/spec/index.bs#L595

wgpu-rs hasn't been updated to reflect that yet. It has to be done before we release 0.3.

[cloudhead]

Ah amazing! Yeah I don't think push constant support is necessary if we have dynamic offsets. Good to know they are coming 👍

In the time being I'll try to work around it with vertex buffers 🤔

[cloudhead]

I'm happy to look into it also.

[kvark]

You are welcome to make a PR introducing the dynamic offsets, if willing to help ;)