Reduces memory peak during window resize

source/ps/VideoMode.cpp

@@ -875,11 +875,13 @@ void CVideoMode::UpdateRenderer(int w, int h)
 
 	SViewPort vp = { 0, 0, w, h };
 
+	// We need to separate destroy and create of objects to be able to flush
+	// all queued to destroy resources during WaitUntilIdle.
+	if (CRenderer::IsInitialised())
+		g_Renderer.DestroyViewSizeDependentObjects();
+
 	if (g_VideoMode.m_BackendDevice)
 	{
-		// TODO: implement freeing window size dependent resources before
-		// waiting to reduce a memory spike.
-
 		// We need to wait until we can destroy the swapchain because it
 		// might be in use.
 		g_VideoMode.m_BackendDevice->WaitUntilIdle();
@@ -888,7 +890,7 @@ void CVideoMode::UpdateRenderer(int w, int h)
 	}
 
 	if (CRenderer::IsInitialised())
-		g_Renderer.Resize(w, h);
+		g_Renderer.CreateViewSizeDependentObjects(w, h);
 
 	if (g_GUI)
 		g_GUI->UpdateResolution();

source/renderer/PostprocManager.cpp

@@ -103,11 +103,6 @@ CPostprocManager::CPostprocManager(Renderer::Backend::IDevice* device)
 {
 }
 
-CPostprocManager::~CPostprocManager()
-{
-	Cleanup();
-}
-
 bool CPostprocManager::IsEnabled() const
 {
 	const bool isDepthStencilFormatPresent =
@@ -143,7 +138,7 @@ void CPostprocManager::Cleanup()
 	}
 }
 
-void CPostprocManager::Initialize()
+void CPostprocManager::Initialize(const uint32_t width, const uint32_t height)
 {
 	if (m_IsInitialized)
 		return;
@@ -168,8 +163,9 @@ void CPostprocManager::Initialize()
 		std::back_inserter(m_AllowedSampleCounts),
 		[maxSamples](const uint32_t sampleCount) { return sampleCount <= maxSamples; } );
 
-	// The screen size starts out correct and then must be updated with Resize()
-	RecalculateSize(g_Renderer.GetWidth(), g_Renderer.GetHeight());
+	// The screen size starts out correct and then must be updated with
+	// Create/DestroyViewSizeDependentObjects()
+	RecalculateSize(width, height);
 
 	RecreateBuffers();
 	m_IsInitialized = true;
@@ -229,15 +225,27 @@ void CPostprocManager::InitializePBR()
 	}
 }
 
-void CPostprocManager::Resize()
+void CPostprocManager::Recreate()
 {
-	RecalculateSize(g_Renderer.GetWidth(), g_Renderer.GetHeight());
+	DestroyViewSizeDependentObjects();
+	CreateViewSizeDependentObjects(m_UnscaledWidth, m_UnscaledHeight);
+}
+
+void CPostprocManager::CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height)
+{
+	RecalculateSize(width, height);
 
 	// If the buffers were intialized, recreate them to the new size.
 	if (m_IsInitialized)
 		RecreateBuffers();
 }
 
+void CPostprocManager::DestroyViewSizeDependentObjects()
+{
+	Cleanup();
+	DestroyMultisampleBuffer();
+}
+
 void CPostprocManager::RecreateBuffers()
 {
 	Cleanup();
@@ -986,8 +994,6 @@ void CPostprocManager::CreateMultisampleBuffer()
 
 void CPostprocManager::DestroyMultisampleBuffer()
 {
-	if (m_UsingMultisampleBuffer)
-		return;
 	m_MultisampleFramebuffer.reset();
 	m_MultisampleColorTex.reset();
 	m_MultisampleDepthTex.reset();

source/renderer/PostprocManager.h

@@ -37,17 +37,19 @@ class CPostprocManager
 {
 public:
 	CPostprocManager(Renderer::Backend::IDevice* device);
-	~CPostprocManager();
 
 	// Returns true if the the manager can be used.
 	bool IsEnabled() const;
 
 	// Create all buffers/textures in GPU memory and set default effect.
 	// @note Must be called before using in the renderer. May be called multiple times.
-	void Initialize();
+	void Initialize(const uint32_t width, const uint32_t height);
 
-	// Update the size of the screen
-	void Resize();
+	// Recreate needed resources. Useful to call on settings changes.
+	void Recreate();
+
+	void CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height);
+	void DestroyViewSizeDependentObjects();
 
 	// Returns a list of xml files found in shaders/effects/postproc.
 	static std::vector<CStrW> GetPostEffects();

source/renderer/Renderer.cpp

@@ -476,7 +476,7 @@ void CRenderer::ReloadShaders()
 	m->ShadersDirty = false;
 }
 
-bool CRenderer::Open(int width, int height)
+bool CRenderer::Open(const uint32_t width, const uint32_t height)
 {
 	m->IsOpen = true;
 
@@ -487,21 +487,27 @@ bool CRenderer::Open(int width, int height)
 	m->debugRenderer.Initialize();
 
 	if (m->postprocManager.IsEnabled())
-		m->postprocManager.Initialize();
+		m->postprocManager.Initialize(width, height);
 
-	m->sceneRenderer.Initialize();
+	m->sceneRenderer.Initialize(width, height);
 
 	return true;
 }
 
-void CRenderer::Resize(int width, int height)
+void CRenderer::CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height)
 {
 	m_Width = width;
 	m_Height = height;
 
-	m->postprocManager.Resize();
+	m->postprocManager.CreateViewSizeDependentObjects(width, height);
 
-	m->sceneRenderer.Resize(width, height);
+	m->sceneRenderer.CreateViewSizeDependentObjects(width, height);
+}
+
+void CRenderer::DestroyViewSizeDependentObjects()
+{
+	m->sceneRenderer.DestroyViewSizeDependentObjects();
+	m->postprocManager.DestroyViewSizeDependentObjects();
 }
 
 bool CRenderer::ShouldRender() const
@@ -588,7 +594,7 @@ void CRenderer::RenderFrameImpl(
 		CPostprocManager& postprocManager{GetPostprocManager()};
 		if (postprocManager.IsEnabled())
 		{
-			postprocManager.Initialize();
+			postprocManager.Initialize(m_Width, m_Height);
 			RenderGameWithPostProcessingAndGUI(
 				swapChain, gameView, postprocManager, renderGUI, renderLogger);
 		}
@@ -897,7 +903,10 @@ void CRenderer::RenderBigScreenShot(const bool needsPresent)
 
 	// Resize various things so that the sizes and aspect ratios are correct
 	{
-		g_Renderer.Resize(tileWidth, tileHeight);
+		DestroyViewSizeDependentObjects();
+		m->device->WaitUntilIdle();
+		CreateViewSizeDependentObjects(tileWidth, tileHeight);
+
 		SViewPort vp = { 0, 0, tileWidth, tileHeight };
 		g_Game->GetView()->SetViewport(vp);
 	}
@@ -948,8 +957,12 @@ void CRenderer::RenderBigScreenShot(const bool needsPresent)
 
 	// Restore the viewport settings
 	{
-		g_Renderer.Resize(g_VideoMode.GetWindowWidth(), g_VideoMode.GetWindowHeight());
+		DestroyViewSizeDependentObjects();
+		m->device->WaitUntilIdle();
+
 		SViewPort vp = { 0, 0, g_VideoMode.GetWindowWidth(), g_VideoMode.GetWindowHeight() };
+		CreateViewSizeDependentObjects(vp.m_Width, vp.m_Height);
+
 		g_Game->GetView()->SetViewport(vp);
 		g_Game->GetView()->SetCamera(oldCamera);
 	}

source/renderer/Renderer.h

@@ -82,10 +82,10 @@ public:
 	~CRenderer();
 
 	// open up the renderer: performs any necessary initialisation
-	bool Open(int width, int height);
+	bool Open(const uint32_t width, const uint32_t height);
 
-	// resize renderer view
-	void Resize(int width, int height);
+	void CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height);
+	void DestroyViewSizeDependentObjects();
 
 	// return view width
 	int GetWidth() const { return m_Width; }

source/renderer/RenderingOptions.cpp

@@ -170,7 +170,7 @@ void CRenderingOptions::ReadConfigAndSetupHooks()
 	m_ConfigHooks->Setup("renderer.scale", []()
 		{
 			if (CRenderer::IsInitialised())
-				g_Renderer.GetPostprocManager().Resize();
+				g_Renderer.GetPostprocManager().Recreate();
 		});
 
 	m_ConfigHooks->Setup("renderer.upscale.technique", []()

source/renderer/SceneRenderer.cpp

@@ -365,22 +365,30 @@ void CSceneRenderer::ReloadShaders([[maybe_unused]] Renderer::Backend::IDevice*
 	}
 }
 
-void CSceneRenderer::Initialize()
+void CSceneRenderer::Initialize(const uint32_t width, const uint32_t height)
 {
 	// Let component renderers perform one-time initialization after graphics capabilities and
 	// the shader path have been determined.
 	m->waterManager.Initialize();
 	m->terrainRenderer.Initialize();
 	m->overlayRenderer.Initialize();
+
+	CreateViewSizeDependentObjects(width, height);
 }
 
-// resize renderer view
-void CSceneRenderer::Resize(int /*width*/, int /*height*/)
+void CSceneRenderer::CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height)
 {
 	// need to recreate the shadow map object to resize the shadow texture
-	m->shadow.RecreateTexture();
+	m->shadow.CreateViewSizeDependentObjects(width, height);
 
-	m->waterManager.RecreateOrLoadTexturesIfNeeded();
+	m->waterManager.CreateViewSizeDependentObjects(width, height);
+}
+
+void CSceneRenderer::DestroyViewSizeDependentObjects()
+{
+	m->waterManager.DestroyViewSizeDependentObjects();
+
+	m->shadow.DestroyViewSizeDependentObjects();
 }
 
 void CSceneRenderer::BeginFrame()

source/renderer/SceneRenderer.h

@@ -64,8 +64,10 @@ public:
 	CSceneRenderer(Renderer::Backend::IDevice* device);
 	~CSceneRenderer();
 
-	void Initialize();
-	void Resize(int width, int height);
+	void Initialize(const uint32_t width, const uint32_t height);
+
+	void CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height);
+	void DestroyViewSizeDependentObjects();
 
 	void BeginFrame();
 	void EndFrame();

source/renderer/ShadowMap.cpp

@@ -131,7 +131,7 @@ struct ShadowMapInternals
 	CCamera SavedViewCamera;
 
 	void CalculateShadowMatrices(const int cascade);
-	void CreateTexture();
+	void CreateTexture(const uint32_t width, const uint32_t height);
 	void UpdateCascadesParameters();
 };
 
@@ -227,25 +227,29 @@ ShadowMap::~ShadowMap()
 	delete m;
 }
 
-// Force the texture/buffer/etc to be recreated, particularly when the renderer's
-// size has changed
-void ShadowMap::RecreateTexture()
+void ShadowMap::CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height)
+{
+	m->UpdateCascadesParameters();
+
+	m->CreateTexture(width, height);
+}
+
+void ShadowMap::DestroyViewSizeDependentObjects()
 {
 	m->Framebuffer.reset();
 	m->Texture.reset();
 	m->DummyTexture.reset();
+}
 
-	m->UpdateCascadesParameters();
-
-	// (Texture will be constructed in next SetupFrame)
+void ShadowMap::RecreateTexture()
+{
+	DestroyViewSizeDependentObjects();
+	CreateViewSizeDependentObjects(g_Renderer.GetWidth(), g_Renderer.GetHeight());
 }
 
 // SetupFrame: camera and light direction for this frame
 void ShadowMap::SetupFrame(const CCamera& camera, const CVector3D& lightdir)
 {
-	if (!m->Texture)
-		m->CreateTexture();
-
 	CVector3D x(0, 1, 0), eyepos;
 
 	CVector3D z = lightdir;
@@ -486,7 +490,7 @@ void ShadowMapInternals::CalculateShadowMatrices(const int cascade)
 }
 
 // Create the shadow map
-void ShadowMapInternals::CreateTexture()
+void ShadowMapInternals::CreateTexture(const uint32_t width, const uint32_t height)
 {
 	// Cleanup
 	Framebuffer.reset();
@@ -509,7 +513,7 @@ void ShadowMapInternals::CreateTexture()
 		break;
 	// Ultra
 	case 2:
-		shadowMapSize = std::max(round_up_to_pow2(std::max(g_Renderer.GetWidth(), g_Renderer.GetHeight())), 4096);
+		shadowMapSize = std::max(round_up_to_pow2(std::max(width, height)), 4096u);
 		break;
 	// Medium as is
 	default:

source/renderer/ShadowMap.h

@@ -42,11 +42,14 @@ public:
 
 	/**
 	 * RecreateTexture: Destroy the current shadow texture and force creation of
-	 * a new one. Useful when the renderer's size has changed and the texture
-	 * should be resized too.
+	 * a new one. Useful when shadows settings have changed and the texture
+	 * should be resized/updated too.
 	 */
 	void RecreateTexture();
 
+	void CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height);
+	void DestroyViewSizeDependentObjects();
+
 	/**
 	 * SetupFrame: Configure light space for the given camera and light direction,
 	 * create the shadow texture if necessary, etc.

source/renderer/WaterManager.cpp

@@ -236,6 +236,31 @@ int WaterManager::LoadWaterTextures()
 	return 0;
 }
 
+void WaterManager::CreateViewSizeDependentObjects(const uint32_t, const uint32_t)
+{
+	RecreateOrLoadTexturesIfNeeded();
+}
+
+void WaterManager::DestroyViewSizeDependentObjects()
+{
+	m_ReflectionFramebuffer.reset();
+	m_ReflectionTexture.reset();
+	m_ReflFboDepthTexture.reset();
+
+	m_ReflectionFramebufferInitialized = false;
+
+	m_RefractionFramebuffer.reset();
+	m_RefractionTexture.reset();
+	m_RefrFboDepthTexture.reset();
+
+	m_RefractionFramebufferInitialized = false;
+
+	m_FancyEffectsFramebuffer.reset();
+	m_FancyEffectsOccludersFramebuffer.reset();
+	m_FancyTexture.reset();
+	m_FancyTextureDepth.reset();
+}
+
 void WaterManager::RecreateOrLoadTexturesIfNeeded()
 {
 	// Use screen-sized textures for minimum artifacts.

source/renderer/WaterManager.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -154,6 +154,9 @@ public:
 	 */
 	void RecreateOrLoadTexturesIfNeeded();
 
+	void CreateViewSizeDependentObjects(const uint32_t width, const uint32_t height);
+	void DestroyViewSizeDependentObjects();
+
 	/**
 	 * ReloadWaterNormalTextures: Reload the normal textures so that changing
 	 * water type in Atlas will actually do the right thing.

source/renderer/backend/vulkan/Device.cpp

@@ -836,6 +836,14 @@ void CDevice::OnPresent()
 	++m_FrameID;
 }
 
+void CDevice::OnSwapChainRecreation()
+{
+	// We're sure that a client must call WaitUntilIdle to be able to
+	// recreate a swapchain.
+	ProcessObjectToDestroyQueue(true);
+	ProcessDeviceObjectToDestroyQueue(true);
+}
+
 bool CDevice::IsTextureFormatSupported(const Format format) const
 {
 	switch (format)

source/renderer/backend/vulkan/Device.h

@@ -164,6 +164,8 @@ public:
 
 	void OnPresent();
 
+	void OnSwapChainRecreation();
+
 	void SetObjectName(VkObjectType type, const void* handle, const char* name)
 	{
 		SetObjectName(type, reinterpret_cast<uint64_t>(handle), name);

source/renderer/backend/vulkan/SwapChain.cpp

@@ -59,6 +59,16 @@ std::unique_ptr<CSwapChain> CSwapChain::Create(
 	int surfaceDrawableWidth, int surfaceDrawableHeight,
 	const bool vsync, std::unique_ptr<ISwapChain> oldSwapChain)
 {
+	// We don't need to wait to destroy the depth texture as it's independent
+	// from VkSwapchainKHR.
+	if (oldSwapChain)
+	{
+		oldSwapChain->As<CSwapChain>()->m_DepthTexture.reset();
+
+		// Workaround to free the depth texture immediately.
+		device->OnSwapChainRecreation();
+	}
+
 	// It seems some drivers might not reuse the same swapchain memory. So
 	// to avoid higher memory peaks destroy the old swapchain before.
 	const bool destroyOldSwapchainBefore{
@@ -225,6 +235,8 @@ std::unique_ptr<CSwapChain> CSwapChain::Create(
 	ENSURE_VK_SUCCESS(getSwapchainImagesResult);
 	ENSURE(imageCount > 0);
 
+	// We create a depth texture to mimic GL behavior where SDL creates it for
+	// a backbuffer.
 	swapChain->m_DepthTexture = CTexture::Create(
 		device, "SwapChainDepthTexture", ITexture::Type::TEXTURE_2D,
 		ITexture::Usage::DEPTH_STENCIL_ATTACHMENT,