Inconsistant limittype specification

[qbojj]

Let us assume that if the limittype contains min for limit alpha then: device->alpha >= limit->alpha (similar holds for max)

As for:

• minMemoryMapAlignment is min,pot then device->minMemoryMapAlignment >= limit
• minStorageBufferOffsetAlignment is also min,pot so device->minStorageBufferOffsetAlignment >= limit

But as minMemoryMapAlignment restricts the device (the higher the limit the better), but minStorageBufferOffsetAlignment restricts the user (the lower the better) maybe (even if it sounds unintuitive) the limits that are restricting the user should have reversed limittypes.

Then we would have minMemoryMapAlignment: min,pot, but minStorageBufferOffsetAlignment would be max,pot, but that would align with the device/user restriction reasoning.

Originally posted by @qbojj in KhronosGroup/Vulkan-Profiles#703 (comment)

[r-potter]

These do seem inconsistent. The Required Limits table in the spec defines minMemoryMapAlignment as >= 64, but minStorageBufferOffsetAlignment <= 256.

[qbojj]

Maybe I should have sent this issue to the XML repo, as minMemoryMapAlignment >= 64, but minStorageBufferOffsetAlignment <= 256 is what I would expect (as stated in the introduction), but the xml sets the limittype to the same value (min,pot)

            <member limittype="bits"><type>uint32_t</type>              <name>viewportSubPixelBits</name><comment>number bits of subpixel precision for viewport</comment></member>
            <member limittype="min,pot"><type>size_t</type>             <name>minMemoryMapAlignment</name><comment>min required alignment of pointers returned by MapMemory (bytes)</comment></member>
            <member limittype="min,pot"><type>VkDeviceSize</type>       <name>minTexelBufferOffsetAlignment</name><comment>min required alignment for texel buffer offsets (bytes) </comment></member>
            <member limittype="min,pot"><type>VkDeviceSize</type>       <name>minUniformBufferOffsetAlignment</name><comment>min required alignment for uniform buffer sizes and offsets (bytes)</comment></member>
            <member limittype="min,pot"><type>VkDeviceSize</type>       <name>minStorageBufferOffsetAlignment</name><comment>min required alignment for storage buffer offsets (bytes)</comment></member>
            <member limittype="min"><type>int32_t</type>                <name>minTexelOffset</name><comment>min texel offset for OpTextureSampleOffset</comment></member>
            <member limittype="max"><type>uint32_t</type>               <name>maxTexelOffset</name><comment>max texel offset for OpTextureSampleOffset</comment></member>

[oddhack]

Maybe I should have sent this issue to the XML repo

Vulkan-Docs holds the canonical version of vk.xml, if that's what you mean by "XML repo".

[oddhack]

This should be fixed in the 1.4.304 spec update.