[SwapChain] Added IsPresentable() to SwapChain interface.

This new function allows to detect when the native surface of a swap-chain is temporarily unavailable. This occurs when a mobile app is paused and the native surface is destroyed, while it is later re-initialized when the app resumes. Also moved all SwapChain interface declarations to Backend/SwapChain.inl header as for other interfaces with more than one or two functions.
LukasBanana · Aug 8, 2024 · 2232eb6 · 2232eb6
1 parent b78b7e3
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Showing 34 changed files with 241 additions and 127 deletions.
diff --git a/examples/Cpp/ExampleBase/ExampleBase.cpp b/examples/Cpp/ExampleBase/ExampleBase.cpp
@@ -11,6 +11,7 @@
 #include "ImageReader.h"
 #include "FileUtils.h"
 #include <stdio.h>
+#include <thread>
 
 #define STB_IMAGE_IMPLEMENTATION
 #include <stb/stb_image.h>
@@ -380,13 +381,25 @@ void ExampleBase::Run()
     bool fullscreen = false;
     const LLGL::Extent2D initialResolution = swapChain->GetResolution();
 
-    #ifdef LLGL_MOBILE_PLATFORM
-    while (LLGL::Surface::ProcessEvents())
-    #else
+    #ifndef LLGL_MOBILE_PLATFORM
     LLGL::Window& window = LLGL::CastTo<LLGL::Window>(swapChain->GetSurface());
-    while (LLGL::Surface::ProcessEvents() && !window.HasQuit() && !input.KeyDown(LLGL::Key::Escape))
     #endif
+
+    while (LLGL::Surface::ProcessEvents() && !input.KeyDown(LLGL::Key::Escape))
     {
+        #ifndef LLGL_MOBILE_PLATFORM
+        // On desktop platforms, we also want to quit the app if the close button has been pressed
+        if (window.HasQuit())
+            break;
+        #endif
+
+        // On mobile platforms, if app has paused, the swap-chain might not be presentable until the app is resumed again
+        if (!swapChain->IsPresentable())
+        {
+            std::this_thread::yield();
+            continue;
+        }
+
         #ifdef LLGL_OS_ANDROID
         if (input.KeyDown(LLGL::Key::BrowserBack))
             ANativeActivity_finish(ExampleBase::androidApp_->activity);
@@ -484,17 +497,20 @@ ExampleBase::ExampleBase(const LLGL::UTF8String& title)
     LLGL::RenderSystemDescriptor rendererDesc = g_Config.rendererModule;
 
     #if defined LLGL_OS_ANDROID
-    LLGL::RendererConfigurationOpenGL cfgGL;
-    if (android_app* app = ExampleBase::androidApp_)
+    if (rendererDesc.moduleName == "OpenGLES3")
     {
-        rendererDesc.androidApp         = app;
-        cfgGL.majorVersion = 3;
-        cfgGL.minorVersion = 1;
-        rendererDesc.rendererConfig     = &cfgGL;
-        rendererDesc.rendererConfigSize = sizeof(cfgGL);
+        LLGL::RendererConfigurationOpenGL cfgGL;
+        if (android_app* app = ExampleBase::androidApp_)
+        {
+            rendererDesc.androidApp         = app;
+            cfgGL.majorVersion = 3;
+            cfgGL.minorVersion = 1;
+            rendererDesc.rendererConfig     = &cfgGL;
+            rendererDesc.rendererConfigSize = sizeof(cfgGL);
+        }
+        else
+            throw std::invalid_argument("'android_app' state was not specified");
     }
-    else
-        throw std::invalid_argument("'android_app' state was not specified");
     #endif
 
     if (g_Config.debugger)

diff --git a/include/LLGL-C/SwapChain.h b/include/LLGL-C/SwapChain.h
@@ -14,6 +14,7 @@
 #include <stdint.h>
 
 
+LLGL_C_EXPORT bool llglIsPresentable(LLGLSwapChain swapChain);
 LLGL_C_EXPORT void llglPresent(LLGLSwapChain swapChain);
 LLGL_C_EXPORT uint32_t llglGetCurrentSwapIndex(LLGLSwapChain swapChain);
 LLGL_C_EXPORT uint32_t llglGetNumSwapBuffers(LLGLSwapChain swapChain);

diff --git a/include/LLGL/Backend/SwapChain.inl b/include/LLGL/Backend/SwapChain.inl
@@ -0,0 +1,46 @@
+/*
+ * SwapChain.inl
+ *
+ * Copyright (c) 2015 Lukas Hermanns. All rights reserved.
+ * Licensed under the terms of the BSD 3-Clause license (see LICENSE.txt).
+ */
+
+virtual bool IsPresentable(
+    void
+) const override final;
+
+virtual void Present(
+    void
+) override final;
+
+virtual std::uint32_t GetCurrentSwapIndex(
+    void
+) const override final;
+
+virtual std::uint32_t GetNumSwapBuffers(
+    void
+) const override final;
+
+virtual std::uint32_t GetSamples(
+    void
+) const override final;
+
+virtual LLGL::Format GetColorFormat(
+    void
+) const override final;
+
+virtual LLGL::Format GetDepthStencilFormat(
+    void
+) const override final;
+
+virtual const LLGL::RenderPass* GetRenderPass(
+    void
+) const override;
+
+virtual bool SetVsyncInterval(
+    std::uint32_t vsyncInterval
+) override final;
+
+
+
+// ================================================================================
diff --git a/include/LLGL/SwapChain.h b/include/LLGL/SwapChain.h
@@ -76,6 +76,28 @@ class LLGL_EXPORT SwapChain : public RenderTarget
 
         /* ----- Back Buffer ----- */
 
+        /**
+        \brief Returns true if this swap-chain is ready for rendering and presenting. Otherwise, the native surface or back buffer are not available.
+        \remarks This is mostly used for mobile platforms where the surface can be temporarily destroyed when the app is paused and later re-initialized when the app resumes.
+        If this is false, no rendering to this swap-chain must be performed nor can the back buffer be presented.
+        \remarks A safe way to handle the event of a lost native surface is to skip the entire rendering when this returns false as shown below:
+        \code
+        while (LLGL::Surface::ProcessEvents()) {
+            // Skip frame if swap-chain is currently not presentable
+            if (!swapChain->IsPresentable()) {
+                std::this_thread::yield();
+                continue;
+            }
+
+            // Render frame ...
+
+            // Present swap-chain back buffer
+            swapChain->Present();
+        }
+        \endcode
+        */
+        virtual bool IsPresentable() const = 0;
+
         /**
         \brief Swaps the current back buffer with the front buffer to present it on the screen.
         \see GetCurrentSwapIndex

diff --git a/sources/Platform/Android/AndroidCanvas.cpp b/sources/Platform/Android/AndroidCanvas.cpp
@@ -34,12 +34,6 @@ bool Surface::ProcessEvents()
             if (source != nullptr)
                 source->process(app, source);
 
-            /* Process sensor data */
-            /*if (ident == LOOPER_ID_USER)
-            {
-                //TODO
-            }*/
-
             /* Check if we are exiting */
             if (app->destroyRequested != 0)
                 return false;

diff --git a/sources/Renderer/DebugLayer/DbgCommandBuffer.cpp b/sources/Renderer/DebugLayer/DbgCommandBuffer.cpp
@@ -743,6 +743,14 @@ void DbgCommandBuffer::BeginRenderPass(
     {
         auto& swapChainDbg = LLGL_DBG_CAST(DbgSwapChain&, renderTarget);
 
+        if (!swapChainDbg.IsPresentable())
+        {
+            LLGL_DBG_ERROR(
+                ErrorType::InvalidState,
+                "cannot begin new render pass with swap chain that is not presentable"
+            );
+        }
+
         swapChainDbg.NotifyNextRenderPass(debugger_, renderPass);
 
         bindings_.swapChain     = &swapChainDbg;

diff --git a/sources/Renderer/DebugLayer/DbgSwapChain.cpp b/sources/Renderer/DebugLayer/DbgSwapChain.cpp
@@ -52,6 +52,11 @@ void DbgSwapChain::SetDebugName(const char* name)
     DbgSetObjectName(*this, name);
 }
 
+bool DbgSwapChain::IsPresentable() const
+{
+    return instance.IsPresentable();
+}
+
 void DbgSwapChain::Present()
 {
     instance.Present();

diff --git a/sources/Renderer/DebugLayer/DbgSwapChain.h b/sources/Renderer/DebugLayer/DbgSwapChain.h
@@ -32,20 +32,11 @@ class DbgSwapChain final : public SwapChain
 
     public:
 
-        void SetDebugName(const char* name) override;
-
-        void Present() override;
-
-        std::uint32_t GetCurrentSwapIndex() const override;
-        std::uint32_t GetNumSwapBuffers() const override;
-        std::uint32_t GetSamples() const override;
+        #include <LLGL/Backend/SwapChain.inl>
 
-        Format GetColorFormat() const override;
-        Format GetDepthStencilFormat() const override;
-
-        bool SetVsyncInterval(std::uint32_t vsyncInterval) override;
+    public:
 
-        const RenderPass* GetRenderPass() const override;
+        void SetDebugName(const char* name) override;
 
     public:
 

diff --git a/sources/Renderer/Direct3D11/D3D11SwapChain.cpp b/sources/Renderer/Direct3D11/D3D11SwapChain.cpp
@@ -79,6 +79,11 @@ void D3D11SwapChain::SetDebugName(const char* name)
     }
 }
 
+bool D3D11SwapChain::IsPresentable() const
+{
+    return true; // dummy
+}
+
 void D3D11SwapChain::Present()
 {
     const bool tearingEnabled   = (tearingSupported_ && windowedMode_ && swapChainInterval_ == 0);

diff --git a/sources/Renderer/Direct3D11/D3D11SwapChain.h b/sources/Renderer/Direct3D11/D3D11SwapChain.h
@@ -29,6 +29,10 @@ class D3D11RenderSystem;
 class D3D11SwapChain final : public SwapChain
 {
 
+    public:
+
+        #include <LLGL/Backend/SwapChain.inl>
+
     public:
 
         D3D11SwapChain(
@@ -41,19 +45,6 @@ class D3D11SwapChain final : public SwapChain
 
         void SetDebugName(const char* name) override;
 
-        void Present() override;
-
-        std::uint32_t GetCurrentSwapIndex() const override;
-        std::uint32_t GetNumSwapBuffers() const override;
-        std::uint32_t GetSamples() const override;
-
-        Format GetColorFormat() const override;
-        Format GetDepthStencilFormat() const override;
-
-        const RenderPass* GetRenderPass() const override;
-
-        bool SetVsyncInterval(std::uint32_t vsyncInterval) override;
-
     public:
 
         // Copyies a subresource region from the backbuffer (color or depth-stencil) into the destination resource.

diff --git a/sources/Renderer/Direct3D12/D3D12SwapChain.cpp b/sources/Renderer/Direct3D12/D3D12SwapChain.cpp
@@ -108,6 +108,11 @@ void D3D12SwapChain::SetDebugName(const char* name)
     }
 }
 
+bool D3D12SwapChain::IsPresentable() const
+{
+    return true; // dummy
+}
+
 void D3D12SwapChain::Present()
 {
     /* Present swap-chain with vsync interval */

diff --git a/sources/Renderer/Direct3D12/D3D12SwapChain.h b/sources/Renderer/Direct3D12/D3D12SwapChain.h
@@ -36,20 +36,11 @@ class D3D12SwapChain final : public SwapChain
 
     public:
 
-        void SetDebugName(const char* name) override;
-
-        void Present() override;
-
-        std::uint32_t GetCurrentSwapIndex() const override;
-        std::uint32_t GetNumSwapBuffers() const override;
-        std::uint32_t GetSamples() const override;
+        #include <LLGL/Backend/SwapChain.inl>
 
-        Format GetColorFormat() const override;
-        Format GetDepthStencilFormat() const override;
-
-        const RenderPass* GetRenderPass() const override;
+    public:
 
-        bool SetVsyncInterval(std::uint32_t vsyncInterval) override;
+        void SetDebugName(const char* name) override;
 
     public:
 

diff --git a/sources/Renderer/Metal/MTSwapChain.h b/sources/Renderer/Metal/MTSwapChain.h
@@ -31,7 +31,9 @@ class MTSwapChain final : public SwapChain
 
     public:
 
-        /* ----- Common ----- */
+        #include <LLGL/Backend/SwapChain.inl>
+
+    public:
 
         MTSwapChain(
             id<MTLDevice>                   device,
@@ -40,19 +42,6 @@ class MTSwapChain final : public SwapChain
             const RendererInfo&             rendererInfo
         );
 
-        void Present() override;
-
-        std::uint32_t GetCurrentSwapIndex() const override;
-        std::uint32_t GetNumSwapBuffers() const override;
-        std::uint32_t GetSamples() const override;
-
-        Format GetColorFormat() const override;
-        Format GetDepthStencilFormat() const override;
-
-        const RenderPass* GetRenderPass() const override;
-
-        bool SetVsyncInterval(std::uint32_t vsyncInterval) override;
-
     public:
 
         // Updates the native render pass descriptor with the specified clear values. Returns null on failure.

diff --git a/sources/Renderer/Metal/MTSwapChain.mm b/sources/Renderer/Metal/MTSwapChain.mm
@@ -75,6 +75,11 @@ - (void)mtkView:(nonnull MTKView *)view drawableSizeWillChange:(CGSize)size
         ShowSurface();
 }
 
+bool MTSwapChain::IsPresentable() const
+{
+    return true; //TODO
+}
+
 void MTSwapChain::Present()
 {
     /* Present backbuffer */

diff --git a/sources/Renderer/Null/NullSwapChain.cpp b/sources/Renderer/Null/NullSwapChain.cpp
@@ -63,6 +63,11 @@ void NullSwapChain::SetDebugName(const char* name)
         label_.clear();
 }
 
+bool NullSwapChain::IsPresentable() const
+{
+    return true; // dummy
+}
+
 void NullSwapChain::Present()
 {
     // dummy

diff --git a/sources/Renderer/Null/NullSwapChain.h b/sources/Renderer/Null/NullSwapChain.h
@@ -22,28 +22,19 @@ class NullSwapChain final : public SwapChain
 
     public:
 
-        NullSwapChain(
-            const SwapChainDescriptor&      desc,
-            const std::shared_ptr<Surface>& surface,
-            const RendererInfo&             rendererInfo
-        );
+        #include <LLGL/Backend/SwapChain.inl>
 
     public:
 
         void SetDebugName(const char* name) override;
 
-        void Present() override;
-
-        std::uint32_t GetCurrentSwapIndex() const override;
-        std::uint32_t GetNumSwapBuffers() const override;
-        std::uint32_t GetSamples() const override;
-
-        Format GetColorFormat() const override;
-        Format GetDepthStencilFormat() const override;
-
-        bool SetVsyncInterval(std::uint32_t vsyncInterval) override;
+    public:
 
-        const RenderPass* GetRenderPass() const override;
+        NullSwapChain(
+            const SwapChainDescriptor&      desc,
+            const std::shared_ptr<Surface>& surface,
+            const RendererInfo&             rendererInfo
+        );
 
     private: