CODEWITHSUNDEEP
cgraphicsgpuvulkan
toastie
toastie

Reputation: 2084

VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT on swapchain ImageViews

I updated my nVidia drivers and suddenly started getting the following validation error:

VUID-vkCmdDrawIndexed-blendEnable-04727(ERROR / SPEC): msgNum: -1979288290 - Validation Error: [ VUID-vkCmdDrawIndexed-blendEnable-04727 ] Object 0: handle = 0x5eb05e000000003b, type = VK_OBJECT_TYPE_PIPELINE; | MessageID = 0x8a06751e | vkCmdDrawIndexed: Image view's format features of the color attachment (0) of the active subpass do not contain VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT bit, but active pipeline's pAttachments[0].blendEnable is not VK_FALSE. The Vulkan spec states: If rasterization is not disabled in the bound graphics pipeline, then for each color attachment in the subpass, if the corresponding image view's format features do not contain VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT, then the blendEnable member of the corresponding element of the pAttachments member of pColorBlendState must be VK_FALSE (https://vulkan.lunarg.com/doc/view/1.3.211.0/windows/1.3-extensions/vkspec.html#VUID-vkCmdDrawIndexed-blendEnable-04727)

Things still render correctly, but I'd like to fix the validation issue.

I am a bit confused as to how I set the VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT flag or if its part of the format vkGetPhysicalDeviceSurfaceFormatsKHR returns.

If it's the former, how do i set it and if it's the latter, how do i draw to it with blending enabled and not get validation errors?

Thank you!

Upvotes: 0

Views: 238

Answers (2)

toastie
toastie

Reputation: 2084

Well, I missed another validation error that gave me the clue to find the issue. I had to update the VkApplicationInfo apiVersion to VK_API_VERSION_1_3. Leaving the answer here in case it helps anyone else.

Upvotes: 0

Nicol Bolas
Nicol Bolas

Reputation: 474266

Format features are not something you set; they're limitations that the Vulkan implementation informs you that you must work within. In particular, format features are properties that restrict how you may use any image with a particular combination of format, tiling, and so forth.

Swapchain images are subject to the same limitations as user-created images. The specification details what the equivalent VkImageCreateInfo would be for a particular vkCreateSwapchainKHR call. So those are the parameters you will need to send to vkGetPhysicalDeviceFormatProperties to see if your implementation supports some particular use of the swapchain image.

Blending is such a use. Apparently, whatever format you used to use allowed blending under the old driver, but this changed. And your code never verified that it was allowed.

Upvotes: 2

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