Fix 1251: Texture Compression BasisU: Missing device extension

[jeroenbakker-atmind]

Description

Sample checks if device contains an extension, but never enabled them.
This PR marks the VK_IMG_format_pvrct extension optional.

Fixes #1251

Note

Requires assets from KhronosGroup/Vulkan-Samples-Assets#27 for testing. The updated images will not be merged due to the deprecation of the extension. A new PR will be created to remove the texture format from the sample.

Note

Currently still under investigation if this works. On MacM2 (1.3.296.0 or 1.4.304.0) the decoding is incorrect See screenshot below, but no validation warnings. Other formats do give correct results.
Could also be related to the new assets. As it wasn't clear how there were originally created.
On Linux (Pro + Mesa AMD PRO W6800) this extension is not supported.

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[asuessenbach]

No matter what, enabling the extension is correct.

But what makes me think about this sample at all: this extension is deprecated (https://registry.khronos.org/vulkan/specs/latest/man/html/VK_IMG_format_pvrtc.html#_deprecation_state)

[jeroenbakker-atmind]

My proposal would be to land this change, but don't land the updated images.
I will also provide a PR to remove the texture format and the references in the documentation. We can discuss the removal in that PR.

[SaschaWillems]

Do you get validation messages for this. I'm not sure if you actually have to enable that extension, as it does not enable features per se. But seeing that the ext is deprecated, we may just remove PVRTC support completely.

[jeroenbakker-atmind]

Yes I got a validation errors using Vulkan SDK 1.4.304.0

VUID-VkImageCreateInfo-format-parameter(ERROR / SPEC): msgNum: 518653028 - Validation Error: [ VUID-VkImageCreateInfo-format-parameter ] | MessageID = 0x1eea0464 | vkCreateImage(): pCreateInfo->format (VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG) requires the extensions VK_IMG_format_pvrtc.
The Vulkan spec states: format must be a valid VkFormat value (https://vulkan.lunarg.com/doc/view/1.4.304.0/mac/1.4-extensions/vkspec.html#VUID-VkImageCreateInfo-format-parameter)
[error] 518653028 - VUID-VkImageCreateInfo-format-parameter: Validation Error: [ VUID-VkImageCreateInfo-format-parameter ] | MessageID = 0x1eea0464 | vkCreateImage(): pCreateInfo->format (VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG) requires the extensions VK_IMG_format_pvrtc.
The Vulkan spec states: format must be a valid VkFormat value (https://vulkan.lunarg.com/doc/view/1.4.304.0/mac/1.4-extensions/vkspec.html#VUID-VkImageCreateInfo-format-parameter)
VUID-VkImageViewCreateInfo-format-parameter(ERROR / SPEC): msgNum: 1626088923 - Validation Error: [ VUID-VkImageViewCreateInfo-format-parameter ] | MessageID = 0x60ec25db | vkCreateImageView(): pCreateInfo->format (VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG) requires the extensions VK_IMG_format_pvrtc.
The Vulkan spec states: format must be a valid VkFormat value (https://vulkan.lunarg.com/doc/view/1.4.304.0/mac/1.4-extensions/vkspec.html#VUID-VkImageViewCreateInfo-format-parameter)
[error] 1626088923 - VUID-VkImageViewCreateInfo-format-parameter: Validation Error: [ VUID-VkImageViewCreateInfo-format-parameter ] | MessageID = 0x60ec25db | vkCreateImageView(): pCreateInfo->format (VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG) requires the extensions VK_IMG_format_pvrtc.
The Vulkan spec states: format must be a valid VkFormat value (https://vulkan.lunarg.com/doc/view/1.4.304.0/mac/1.4-extensions/vkspec.html#VUID-VkImageViewCreateInfo-format-parameter)

[SaschaWillems]

Then it does make sense to enable the extension :)