The open source OpenXR runtime
c/main: Prefer only two swapchain images
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src/xrt/compositor/main/comp_target_swapchain.c
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src/xrt/compositor/main/comp_target_swapchain.c
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extent.height = w2;
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}
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/*
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* For all direct mode outputs 2 is what we want since we want to run
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* lockstep with the display. Most direct mode swapchains only supports
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* FIFO mode, and since there is no commonly available Vulkan API to
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* wait for a specific VBLANK event, even just the latest, we can set
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* the number of images to two and then acquire immediately after
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* present. Since the old images are being displayed and the new can't
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* be flipped this will block until the flip has gone through. Crude but
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* works well enough on both AMD(Mesa) and Nvidia(Blob).
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*
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* When not in direct mode and display to a composited window we
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* probably want 3, but most compositors on Linux sets the minImageCount
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* to 3 anyways so we get what we want.
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*/
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const uint32_t preferred_at_least_image_count = 2;
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// Get the image count.
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const uint32_t preferred_at_least_image_count = 3;
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uint32_t image_count = select_image_count(cts, surface_caps, preferred_at_least_image_count);
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