From c548212d42b0565aff127c2a52ba24e42350d3ba Mon Sep 17 00:00:00 2001
From: Adrian Cojocaru <adrian.cojocaru92@yahoo.com>
Date: Tue, 3 Dec 2024 23:03:06 +0200
Subject: [PATCH] Add latency to surface updates (#3056)

---
 include/mbgl/vulkan/context.hpp |  3 ++-
 src/mbgl/vulkan/context.cpp     | 22 +++++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/include/mbgl/vulkan/context.hpp b/include/mbgl/vulkan/context.hpp
index e17160d65..08e439df3 100644
--- a/include/mbgl/vulkan/context.hpp
+++ b/include/mbgl/vulkan/context.hpp
@@ -146,7 +146,7 @@ public:
     void enqueueDeletion(std::function<void(Context&)>&& function);
     void submitOneTimeCommand(const std::function<void(const vk::UniqueCommandBuffer&)>& function) const;
 
-    void requestSurfaceUpdate() { surfaceUpdateRequested = true; }
+    void requestSurfaceUpdate(bool useDelay = true);
 
 private:
     struct FrameResources {
@@ -197,6 +197,7 @@ private:
     uint8_t frameResourceIndex = 0;
     std::vector<FrameResources> frameResources;
     bool surfaceUpdateRequested{false};
+    int32_t surfaceUpdateLatency{0};
     int32_t currentFrameCount{0};
 
     struct {
diff --git a/src/mbgl/vulkan/context.cpp b/src/mbgl/vulkan/context.cpp
index 1acb4d691..9f54ebed2 100644
--- a/src/mbgl/vulkan/context.cpp
+++ b/src/mbgl/vulkan/context.cpp
@@ -171,6 +171,19 @@ void Context::submitOneTimeCommand(const std::function<void(const vk::UniqueComm
     }
 }
 
+void Context::requestSurfaceUpdate(bool useDelay) {
+    if (surfaceUpdateRequested) {
+        if (!useDelay) {
+            surfaceUpdateLatency = 0;
+        }
+
+        return;
+    }
+
+    surfaceUpdateRequested = true;
+    surfaceUpdateLatency = useDelay ? backend.getMaxFrames() * 3 : 0;
+}
+
 void Context::waitFrame() const {
     MLN_TRACE_FUNC();
     const auto& device = backend.getDevice();
@@ -203,7 +216,7 @@ void Context::beginFrame() {
         }
     }
 
-    if (platformSurface && surfaceUpdateRequested) {
+    if (platformSurface && surfaceUpdateRequested && --surfaceUpdateLatency <= 0) {
         renderableResource.recreateSwapchain();
 
         // we wait for an idle device to recreate the swapchain
@@ -243,14 +256,13 @@ void Context::beginFrame() {
             if (acquireImageResult.result == vk::Result::eSuccess) {
                 renderableResource.setAcquiredImageIndex(acquireImageResult.value);
             } else if (acquireImageResult.result == vk::Result::eSuboptimalKHR) {
+                renderableResource.setAcquiredImageIndex(acquireImageResult.value);
                 requestSurfaceUpdate();
-                beginFrame();
-                return;
             }
 
         } catch (const vk::OutOfDateKHRError& e) {
             // request an update and restart frame
-            requestSurfaceUpdate();
+            requestSurfaceUpdate(false);
             beginFrame();
             return;
         }
@@ -310,7 +322,7 @@ void Context::submitFrame() {
                 requestSurfaceUpdate();
             }
         } catch (const vk::OutOfDateKHRError& e) {
-            requestSurfaceUpdate();
+            requestSurfaceUpdate(false);
         }
     }