Merge pull request #22178 from saboten731/pr/libretro-vulkan-presentation-handoff

Libretro Vulkan: wait for presentation handoff completion

Common/GPU/Vulkan/VulkanPresentation.h

@@ -31,6 +31,11 @@ public:
 	// Mirrors vkQueuePresentKHR: hands the finished image back, waiting on waitSemaphore first.
 	virtual VkResult QueuePresent(VulkanContext *vulkan, VkQueue queue, uint32_t imageIndex, VkSemaphore waitSemaphore) = 0;
 
+	// Called around a queued presentation. Hosts that hand an image to another thread can use this
+	// to keep the caller from invoking its video callback until QueuePresent has completed.
+	virtual void BeginPresent() {}
+	virtual void EndPresent() {}
+
 	virtual uint32_t GetImageCount() const = 0;
 	virtual VkImage GetImage(uint32_t index) const = 0;
 	virtual VkExtent2D GetExtent() const = 0;

Common/GPU/Vulkan/VulkanRenderManager.cpp

@@ -1620,6 +1620,9 @@ void VulkanRenderManager::Finish() {
 
 void VulkanRenderManager::Present() {
 	int curFrame = vulkan_->GetCurFrame();
+	if (VulkanPresentation *presentation = vulkan_->GetPresentation()) {
+		presentation->BeginPresent();
+	}
 
 	VKRRenderThreadTask *task = new VKRRenderThreadTask(VKRRunType::PRESENT);
 	task->frame = curFrame;
@@ -1671,6 +1674,9 @@ void VulkanRenderManager::Run(VKRRenderThreadTask &task) {
 			}
 			frameData.skipSwap = false;
 		}
+		if (VulkanPresentation *presentation = vulkan_->GetPresentation()) {
+			presentation->EndPresent();
+		}
 		return;
 	}
 

libretro/LibretroVulkanPresentation.cpp

@@ -106,8 +106,8 @@ void LibretroVulkanPresentation::Destroy(VulkanContext *context) {
 	images_.clear();
 	syncIndexMask_ = 0;
 	std::lock_guard<std::mutex> lock(mutex_);
-	currentIndex_ = -1;
-	everPresented_ = false;
+	presentPending_ = false;
+	condVar_.notify_all();
 }
 
 bool LibretroVulkanPresentation::NeedsRecreate() const {
@@ -138,13 +138,21 @@ VkResult LibretroVulkanPresentation::QueuePresent(VulkanContext *vulkan, VkQueue
 		return VK_ERROR_OUT_OF_DATE_KHR;
 	}
 	std::unique_lock<std::mutex> lock(mutex_);
-	currentIndex_ = (int)imageIndex;
 	vulkan_->set_image(vulkan_->handle, &images_[imageIndex].retroImage, 0, nullptr, vulkan_->queue_index);
-	everPresented_ = true;
-	condVar_.notify_all();
 	return VK_SUCCESS;
 }
 
+void LibretroVulkanPresentation::BeginPresent() {
+	std::lock_guard<std::mutex> lock(mutex_);
+	presentPending_ = true;
+}
+
+void LibretroVulkanPresentation::EndPresent() {
+	std::lock_guard<std::mutex> lock(mutex_);
+	presentPending_ = false;
+	condVar_.notify_all();
+}
+
 void LibretroVulkanPresentation::LockQueue() {
 	vulkan_->lock_queue(vulkan_->handle);
 }
@@ -162,7 +170,5 @@ void LibretroVulkanPresentation::PrepareSubmit(VkSubmitInfo &submitInfo) {
 
 void LibretroVulkanPresentation::WaitForPresentation() {
 	std::unique_lock<std::mutex> lock(mutex_);
-	if (everPresented_ && currentIndex_ < 0) {
-		condVar_.wait(lock);
-	}
+	condVar_.wait(lock, [this] { return !presentPending_; });
 }

libretro/LibretroVulkanPresentation.h

@@ -30,6 +30,8 @@ public:
 
 	VkResult AcquireNextImage(VulkanContext *vulkan, VkSemaphore signalSemaphore, uint32_t *imageIndex) override;
 	VkResult QueuePresent(VulkanContext *vulkan, VkQueue queue, uint32_t imageIndex, VkSemaphore waitSemaphore) override;
+	void BeginPresent() override;
+	void EndPresent() override;
 
 	uint32_t GetImageCount() const override { return (uint32_t)images_.size(); }
 	VkImage GetImage(uint32_t index) const override { return images_[index].image; }
@@ -65,8 +67,7 @@ private:
 
 	std::mutex mutex_;
 	std::condition_variable condVar_;
-	int currentIndex_ = -1;
-	bool everPresented_ = false;
+	bool presentPending_ = false;
 
 	static uint32_t ImageCountFromMask(uint32_t mask);
 	bool IsValidImageIndex(uint32_t imageIndex) const;