SwapchainBuilder: provide some control over minImageCount

This commit is contained in:
Yoan Lecoq 2022-05-16 11:20:01 +02:00 committed by Charles Giessen
parent f847ab8566
commit 5ac2b21dfe
2 changed files with 28 additions and 1 deletions

View File

@ -1774,10 +1774,18 @@ detail::Result<Swapchain> SwapchainBuilder::build() const {
return detail::Error{ SwapchainError::failed_query_surface_support_details, surface_support_ret.vk_result() }; return detail::Error{ SwapchainError::failed_query_surface_support_details, surface_support_ret.vk_result() };
auto surface_support = surface_support_ret.value(); auto surface_support = surface_support_ret.value();
uint32_t image_count = surface_support.capabilities.minImageCount + 1; uint32_t image_count;
if (info.min_image_count == 0) {
image_count = surface_support.capabilities.minImageCount + info.add_to_min_image_count;
} else {
image_count = info.min_image_count;
if (image_count < surface_support.capabilities.minImageCount)
image_count = surface_support.capabilities.minImageCount;
}
if (surface_support.capabilities.maxImageCount > 0 && image_count > surface_support.capabilities.maxImageCount) { if (surface_support.capabilities.maxImageCount > 0 && image_count > surface_support.capabilities.maxImageCount) {
image_count = surface_support.capabilities.maxImageCount; image_count = surface_support.capabilities.maxImageCount;
} }
VkSurfaceFormatKHR surface_format = VkSurfaceFormatKHR surface_format =
detail::find_surface_format(info.physical_device, surface_support.formats, desired_formats, info.format_feature_flags); detail::find_surface_format(info.physical_device, surface_support.formats, desired_formats, info.format_feature_flags);
@ -1972,6 +1980,16 @@ SwapchainBuilder& SwapchainBuilder::set_image_array_layer_count(uint32_t array_l
info.array_layer_count = array_layer_count; info.array_layer_count = array_layer_count;
return *this; return *this;
} }
SwapchainBuilder& SwapchainBuilder::set_desired_min_image_count(uint32_t min_image_count) {
info.min_image_count = min_image_count;
info.add_to_min_image_count = 0; // Unnecessary, but let's do it for clarity
return *this;
}
SwapchainBuilder& SwapchainBuilder::use_default_min_image_count(uint32_t add_to_min_image_count = 1) {
info.min_image_count = 0;
info.add_to_min_image_count = add_to_min_image_count;
return *this;
}
SwapchainBuilder& SwapchainBuilder::set_clipped(bool clipped) { SwapchainBuilder& SwapchainBuilder::set_clipped(bool clipped) {
info.clipped = clipped; info.clipped = clipped;
return *this; return *this;

View File

@ -846,6 +846,13 @@ class SwapchainBuilder {
// Set the number of views in for multiview/stereo surface // Set the number of views in for multiview/stereo surface
SwapchainBuilder& set_image_array_layer_count(uint32_t array_layer_count); SwapchainBuilder& set_image_array_layer_count(uint32_t array_layer_count);
// Sets the desired minimum image count for the swapchain. Note that the presentation engine is always free to create more images than requested.
SwapchainBuilder& set_desired_min_image_count(uint32_t min_image_count);
// Use the default desired minimum image count for the swapchain. The chosen value is calculated as `capabilitites.minImageCount + add_to_min_image_count`.
// The default behavior so far was equivalent to setting `add_to_min_image_count` to 1, and generally led to a triple buffering setup.
// A discussion of the trade-offs involved between double buffering and triple buffering is available as https://en.wikipedia.org/wiki/Multiple_buffering
SwapchainBuilder& use_default_min_image_count(uint32_t add_to_min_image_count = 1);
// Set whether the Vulkan implementation is allowed to discard rendering operations that // Set whether the Vulkan implementation is allowed to discard rendering operations that
// affect regions of the surface that are not visible. Default is true. // affect regions of the surface that are not visible. Default is true.
// Note: Applications should use the default of true if they do not expect to read back the content // Note: Applications should use the default of true if they do not expect to read back the content
@ -884,6 +891,8 @@ class SwapchainBuilder {
uint32_t desired_width = 256; uint32_t desired_width = 256;
uint32_t desired_height = 256; uint32_t desired_height = 256;
uint32_t array_layer_count = 1; uint32_t array_layer_count = 1;
uint32_t min_image_count = 0;
uint32_t add_to_min_image_count = 1; // Keep in sync with default parameter value in use_default_min_image_count()
VkImageUsageFlags image_usage_flags = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT; VkImageUsageFlags image_usage_flags = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
VkFormatFeatureFlags format_feature_flags = VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT; VkFormatFeatureFlags format_feature_flags = VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT;
uint32_t graphics_queue_index = 0; uint32_t graphics_queue_index = 0;