CODEWITHSUNDEEP
vulkan
Andrew Tomazos
Andrew Tomazos

Reputation: 68618

Selecting a surface format for the swapchain?

The function vkGetPhysicalDeviceSurfaceFormatsKHR returns a list of supported VkSurfaceFormatKHRs for a given physical device and surface:

struct VkSurfaceFormatKHR {
    VkFormat format;
    VkColorSpaceKHR colorSpace;
};

When creating a swapchain for a surface you must select the required VkFormat and VkColorSpaceKHR in VkSwapchainCreateInfoKHR...

struct VkSwapchainCreateInfoKHR {
    /* ... */
    VkFormat imageFormat;
    VkColorSpaceKHR imageColorSpace;
    /* ... */
};

and these must match one of the VkSurfaceFormatKHRs.

What is a example implementation of a function:

VkSurfaceFormatKHR SelectSurfaceFormat(std::vector<VkSurfaceFormatKHR>)

That selects a VkSurfaceFormatKHR from the multiple VkSurfaceFormatKHRs returned by vkGetPhysicalDeviceSurfaceFormatsKHR in a way that is reasonably general-purpose?

Upvotes: 1

Views: 2594

Answers (1)

Aaron Hull
Aaron Hull

Reputation: 442

You should exercise the same discretion when choosing a format that you would when choosing a physical device.

If you have a preference for color precision, like if you had a preference for physical device capabilities, I suggest building a list of your preferred formats and running a typical for loop to check if they are supported in order.

If you don't have a preference in any way, you might model your app after the LunarG Vulkan Sample project which asserts that size of surfaceFormats > 0 and defaults to surfaceFormats[0].

The sample also handles the case that surfaceFormats[0] == VK_FORMAT_UNDEFINED, but as mentioned in the comments, this is no longer a valid value and may be omitted.

Upvotes: 1

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