Add mip map example

[attackgoat]

No description provided.

[DGriffin91]

It looks like this PR eliminates most of the remaining validation errors in my renderer! There's one relevant case where it might not be using the correct barrier. I have a set of passes like this:

let mut mip = 0;
while width > 1 && height > 1 {
    graph
        .begin_pass("low_z_prepass_pyramid")
        .bind_pipeline([...])
        .read_descriptor_as(0, depth_node, info_mip(dwrite_info, mip))
        .write_descriptor_as(1, depth_node, info_mip(dwrite_info, mip + 1))
        .record_compute(move |compute, _bindings| {
            compute.dispatch(width / 8 + 1, height / 8 + 1, 1);
        });
    width /= 2;
    height /= 2;
    mip += 1;
}

fn info_mip(info: ImageViewInfo, level: u32) -> ImageViewInfo {
    let mut write_info = info;
    write_info.base_mip_level = level;
    write_info.mip_level_count = Some(1);
    write_info
}

And it seems that the read_descriptor_as here transitions the mip to an optimal layout and shader read mask (which seems correct). But then in a subsequent pass I read the whole image (with just read_descriptor) and it tries to transition it a second time from a general layout and shader write to optimal layout and shader read which triggers the validation error:

VUID-VkImageMemoryBarrier-oldLayout-01197(ERROR / SPEC): msgNum: 307231540 - Validation Error: [ VUID-VkImageMemoryBarrier-oldLayout-01197 ] Object 0: handle = 0x2255ff10a30, type = VK_OBJECT_TYPE_COMMAND_BUFFER; Object 1: handle = 0x980b0000000002e, type = VK_OBJECT_TYPE_IMAGE; | MessageID = 0x124ffb34 | vkCmdPipelineBarrier(): pImageMemoryBarriers[0].image (VkImage 0x980b0000000002e[]) cannot transition the layout of aspect=1, level=0, layer=0 from VK_IMAGE_LAYOUT_GENERAL when the previous known layout is VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL. The Vulkan spec states: If srcQueueFamilyIndex and dstQueueFamilyIndex define a queue family ownership transfer or oldLayout and newLayout define an image layout transition, oldLayout must be VK_IMAGE_LAYOUT_UNDEFINED or the current layout of the image subresources affected by the barrier (https://vulkan.lunarg.com/doc/view/1.3.296.0/windows/1.3-extensions/vkspec.html#VUID-VkImageMemoryBarrier-oldLayout-01197)

[DGriffin91]

I did just notice that with this PR I'm getting undefined img in render doc on some attachments and it just renders black on a GTX1060. Still need to track down the cause or make a minimal reproduction. Just wanted to mention. (I tried a few of the basic examples in this repo and it didn't occur, though there were other vulkan validation errors)