#lockdown Nick.Penwarden
#rb none
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MAJOR FEATURES + CHANGES
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Change 3209340 on 2016/11/23 by Ben.Marsh
Convert UE4 codebase to an "include what you use" model - where every header just includes the dependencies it needs, rather than every source file including large monolithic headers like Engine.h and UnrealEd.h.
Measured full rebuild times around 2x faster using XGE on Windows, and improvements of 25% or more for incremental builds and full rebuilds on most other platforms.
* Every header now includes everything it needs to compile.
* There's a CoreMinimal.h header that gets you a set of ubiquitous types from Core (eg. FString, FName, TArray, FVector, etc...). Most headers now include this first.
* There's a CoreTypes.h header that sets up primitive UE4 types and build macros (int32, PLATFORM_WIN64, etc...). All headers in Core include this first, as does CoreMinimal.h.
* Every .cpp file includes its matching .h file first.
* This helps validate that each header is including everything it needs to compile.
* No engine code includes a monolithic header such as Engine.h or UnrealEd.h any more.
* You will get a warning if you try to include one of these from the engine. They still exist for compatibility with game projects and do not produce warnings when included there.
* There have only been minor changes to our internal games down to accommodate these changes. The intent is for this to be as seamless as possible.
* No engine code explicitly includes a precompiled header any more.
* We still use PCHs, but they're force-included on the compiler command line by UnrealBuildTool instead. This lets us tune what they contain without breaking any existing include dependencies.
* PCHs are generated by a tool to get a statistical amount of coverage for the source files using it, and I've seeded the new shared PCHs to contain any header included by > 15% of source files.
Tool used to generate this transform is at Engine\Source\Programs\IncludeTool.
[CL 3209342 by Ben Marsh in Main branch]
- Fewer differences between code paths and clearer name for #define.
- Also removes GL error that was happening due to GL_ALPHA being used with a 3.2 context.
[CL 2487209 by Dmitry Rekman in Main branch]
- PR #526 by yaakuro, with changes. Only core 3.2 is now used.
- Editor is now able to start on Intel Linux drivers (but see UECOMP-116).
#codereview Josh.Adams, Timothy.Lottes, Mark.Satterthwaite
[CL 2339349 by Dmitry Rekman in Main branch]
- New PlatformTearDown() function to correspond to PlatformInit(), called at AppExit() time (unguarded code).
- Linux-specific PlatformInitMultimedia() function (not part of generic platform abstraction) which handles multiple initialization of SDL and/or avoids it for certain targets.
- Fixes problem with SDL message box destroying SDL and ruining things later down the road.
#codereview Josh.Adams, Ankit.Khare, Michael.Trepka, Marcus.Wassmer, Pete.Knepley, Graeme.Thornton
[CL 2263609 by Dmitry Rekman in Main branch]
- SDL2 sources as of revision 8809:4bb098814ec4.
- Dependencies on dsext removed.
- SDL2 will be linked dynamically if the target is modular.
- Slate will refuse to start if unable to get GL funcs.
#codereview Josh.Adams
[CL 2125422 by Dmitry Rekman in Main branch]
- Due to not using vendor headers when cross-compiling, we cannot use deprecated calls like glTexEnvi(). This needs to be later reworked to use another (not-plaform-specific) #define.
#codereview Josh.Adams, Michael.Liebenow, Nick.Penwarden
[CL 2067377 by Dmitry Rekman in Main branch]
