Filament targets c++20 by default (#9080)

Author: poweifeng

CMakeLists.txt

@@ -331,9 +331,9 @@ endif()
 # ==================================================================================================
 # General compiler flags
 # ==================================================================================================
-set(CXX_STANDARD "-std=c++17")
+set(CXX_STANDARD "-std=c++20")
 if (WIN32)
-    set(CXX_STANDARD "/std:c++17")
+    set(CXX_STANDARD "/std:c++20")
 endif()
 
 if (MSVC)

NEW_RELEASE_NOTES.md

@@ -14,3 +14,4 @@ appropriate header in [RELEASE_NOTES.md](./RELEASE_NOTES.md).
   depth-only passes. [**Requires recompiling materials**]
 - material: fix specularFactor in `LOW_QUALITY` mode. [**Requires recompiling materials**] to take effect.
 - material: Add CRC32 validation for material packages [⚠️ **New Material Version**]
+- Filament is now targeting c++20 (was previously c++17)

filament/CMakeLists.txt

@@ -728,13 +728,6 @@ else()
             -Wover-aligned
             -Werror
     )
-    if (CMAKE_CXX_STANDARD EQUAL 20)
-        # The lambdas for passes in PostProcessManager.cpp capture this
-        # implicitly in a way that's deprecated in c++20, but can't easily be
-        # fixed in a way that's backwards compatible with c++17:
-        # https://www.nextptr.com/tutorial/ta1430524603/capture-this-in-lambda-expression-timeline-of-change
-        list(APPEND FILAMENT_WARNINGS -Wno-deprecated-this-capture)
-    endif()
 endif()
 
 target_compile_options(${TARGET} PRIVATE

filament/README.md

@@ -99,7 +99,7 @@ main: main.o
 	$(CC) -Llib/x86_64/ main.o $(FILAMENT_LIBS) -lpthread -lc++ -ldl -o main
 
 main.o: main.cpp
-	$(CC) -Iinclude/ -std=c++17 -pthread -c main.cpp
+	$(CC) -Iinclude/ -std=c++20 -pthread -c main.cpp
 
 clean:
 	rm -f main main.o
@@ -119,7 +119,7 @@ main: main.o
 	$(CC) -Llib/$(ARCH)/ main.o $(FILAMENT_LIBS) $(FRAMEWORKS) -o main
 
 main.o: main.cpp
-	$(CC) -Iinclude/ -std=c++17 -c main.cpp
+	$(CC) -Iinclude/ -std=c++20 -c main.cpp
 
 clean:
 	rm -f main main.o
@@ -148,7 +148,7 @@ main.exe: main.obj
 	gdi32.lib user32.lib opengl32.lib
 
 main.obj: main.cpp
-	$(CC) /MT /Iinclude\\ /std:c++17 /c main.cpp
+	$(CC) /MT /Iinclude\\ /std:c++20 /c main.cpp
 
 clean:
 	del main.exe main.obj

filament/backend/include/private/backend/CommandStream.h

@@ -197,7 +197,10 @@ class NoopCommand : public CommandBase {
     #define DEBUG_COMMAND_END(methodName, sync) mDriver.debugCommandEnd(this, sync, #methodName)
 #else
     #define DEBUG_COMMAND_BEGIN(methodName, sync, ...)
-    #define DEBUG_COMMAND_END(methodName, sync)
+    // For the line "AutoExecute callOnExit([=, this](){",
+    // "this" will be unused for release build since DEBUG_COMMAND_END is a no-op. So we add the
+    // following workaround.
+    #define DEBUG_COMMAND_END(methodName, sync) ((void)(this));
 #endif
 
 class CommandStream {
@@ -229,7 +232,7 @@ class CommandStream {
 #define DECL_DRIVER_API_SYNCHRONOUS(RetType, methodName, paramsDecl, params)                    \
     inline RetType methodName(paramsDecl) {                                                     \
         DEBUG_COMMAND_BEGIN(methodName, true, params);                                          \
-        AutoExecute callOnExit([=](){                                                           \
+        AutoExecute callOnExit([=, this](){                                                     \
             DEBUG_COMMAND_END(methodName, true);                                                \
         });                                                                                     \
         return apply(&Driver::methodName, mDriver, std::forward_as_tuple(params));              \

filament/src/PostProcessManager.cpp

@@ -337,7 +337,8 @@ FrameGraphId<FrameGraphTexture> ShadowMapManager::render(FEngine& engine, FrameG
                 // "read" from one of its resource (only writes), so the FrameGraph culls it.
                 builder.sideEffect();
             },
-            [=, passBuilder = passBuilder,
+            [=, this,
+                    passBuilder = passBuilder,
                     &engine = const_cast<FEngine /*const*/ &>(engine), // FIXME: we want this const
                     &view = const_cast<FView const&>(view)]
                     (FrameGraphResources const&, auto const& data, DriverApi& driver) mutable {

filament/src/ShadowMapManager.cpp

@@ -93,7 +93,7 @@ main: main.o
 	$(CC) -Llib/x86_64/ -stdlib=libc++ main.o $(FILAMENT_LIBS) -lpthread -ldl -o main
 
 main.o: main.cpp
-	$(CC) -Iinclude/ -std=c++17 -stdlib=libc++ -pthread -c main.cpp
+	$(CC) -Iinclude/ -std=c++20 -stdlib=libc++ -pthread -c main.cpp
 
 clean:
 	rm -f main main.o
@@ -111,7 +111,7 @@ main: main.o
 	$(CC) -Llib/x86_64/ main.o $(FILAMENT_LIBS) -o main
 
 main.o: main.cpp
-	$(CC) -Iinclude/ -std=c++17 -c main.cpp
+	$(CC) -Iinclude/ -std=c++20 -c main.cpp
 
 clean:
 	rm -f main main.o
@@ -138,7 +138,7 @@ main.exe: main.obj
 	$(CC) main.obj $(FILAMENT_LIBS) gdi32.lib user32.lib opengl32.lib
 
 main.obj: main.cpp
-	$(CC) /MT /Iinclude/ /std:c++17 /c main.cpp
+	$(CC) /MT /Iinclude/ /std:c++20 /c main.cpp
 
 clean:
 	del main.exe main.obj

libs/filamat/README.md

@@ -197,11 +197,6 @@ if (WEBGL_PTHREADS)
 endif()
 
 set(GLTFIO_WARNINGS -Wall -Werror)
-if (CMAKE_CXX_STANDARD EQUAL 20)
-    # The following things used by AssetLoader.cpp are deprecated in c++20:
-    # wstring_convert and std::codecvt_utf8<char32_t>.
-    list(APPEND GLTFIO_WARNINGS -Wno-deprecated-declarations)
-endif()
 if (NOT MSVC)
     target_compile_options(gltfio_core PRIVATE ${GLTFIO_WARNINGS})
 endif()