diff options
| -rw-r--r-- | demos/cube.c | 54 |
1 files changed, 51 insertions, 3 deletions
diff --git a/demos/cube.c b/demos/cube.c index 81db5b01..543a81ee 100644 --- a/demos/cube.c +++ b/demos/cube.c @@ -925,10 +925,58 @@ static void demo_prepare_buffers(struct demo *demo) { } // The FIFO present mode is guaranteed by the spec to be supported - // and to have no tearing. MAILBOX is another option, but for fast - // rendering apps we could use a lot of gpu power rendering frames - // that are discarded and never displayed + // and to have no tearing. It's a great default present mode to use. VkPresentModeKHR swapchainPresentMode = VK_PRESENT_MODE_FIFO_KHR; + // There are times when you may wish to use another present mode. The + // following code shows how to select them, and the comments provide some + // reasons you may wish to use them. + // + // It should be noted that Vulkan 1.0 doesn't provide a method for + // synchronizing rendering with the presentation engine's display. There + // is a method provided for throttling rendering with the display, but + // there are some presentation engines for which this method will not work. + // If an application doesn't throttle its rendering, and if it renders much + // faster than the refresh rate of the display, this can waste power on + // mobile devices. That is because power is being spent rendering images + // that may never be seen. +//#define DESIRE_VK_PRESENT_MODE_IMMEDIATE_KHR +//#define DESIRE_VK_PRESENT_MODE_MAILBOX_KHR +//#define DESIRE_VK_PRESENT_MODE_FIFO_RELAXED_KHR +#if defined(DESIRE_VK_PRESENT_MODE_IMMEDIATE_KHR) + // VK_PRESENT_MODE_IMMEDIATE_KHR is for applications that don't care about + // tearing, or have some way of synchronizing their rendering with the + // display. + for (size_t i = 0; i < presentModeCount; ++i) { + if (presentModes[i] == VK_PRESENT_MODE_IMMEDIATE_KHR) { + swapchainPresentMode = VK_PRESENT_MODE_IMMEDIATE_KHR; + break; + } + } +#elif defined(DESIRE_VK_PRESENT_MODE_MAILBOX_KHR) + // VK_PRESENT_MODE_MAILBOX_KHR may be useful for applications that + // generally render a new presentable image every refresh cycle, but are + // occasionally early. In this case, the application wants the new image + // to be displayed instead of the previously-queued-for-presentation image + // that has not yet been displayed. + for (size_t i = 0; i < presentModeCount; ++i) { + if (presentModes[i] == VK_PRESENT_MODE_MAILBOX_KHR) { + swapchainPresentMode = VK_PRESENT_MODE_MAILBOX_KHR; + break; + } + } +#elif defined(DESIRE_VK_PRESENT_MODE_FIFO_RELAXED_KHR) + // VK_PRESENT_MODE_FIFO_RELAXED_KHR is for applications that generally + // render a new presentable image every refresh cycle, but are occasionally + // late. In this case (perhaps because of stuttering/latency concerns), + // the application wants the late image to be immediately displayed, even + // though that may mean some tearing. + for (size_t i = 0; i < presentModeCount; ++i) { + if (presentModes[i] == VK_PRESENT_MODE_MAILBOX_KHR) { + swapchainPresentMode = VK_PRESENT_MODE_MAILBOX_KHR; + break; + } + } +#endif // Determine the number of VkImage's to use in the swap chain. // Application desires to only acquire 1 image at a time (which is |