AtlasEngine: Fix debugGlyphGenerationPerformance (microsoft#13757)

`debugGlyphGenerationPerformance` used to only test the performance of
text segmentation/parsing, so I renamed it to `debugTextParsingPerformance`.
The new `debugGlyphGenerationPerformance` actually clears the glyph atlas now.

Additionally this fixes a bug with `debugGeneralPerformance`:
If a `DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT` is requested,
it needs to be used. Since `debugGeneralPerformance` is for testing without
V-Sync, we need to ensure that the waitable object is properly disabled.

src/renderer/atlas/AtlasEngine.cpp

@@ -233,6 +233,11 @@ try
     }
 
     if constexpr (debugGlyphGenerationPerformance)
+    {
+        _r.glyphs = {};
+        _r.tileAllocator = TileAllocator{ _api.fontMetrics.cellSize, _api.sizeInPixel };
+    }
+    if constexpr (debugTextParsingPerformance)
     {
         _api.dirtyRect = til::rect{ 0, 0, _api.cellCount.x, _api.cellCount.y };
     }
@@ -686,7 +691,7 @@ void AtlasEngine::_createSwapChain()
         // * If our background is opaque we can enable "independent" flips by setting DXGI_SWAP_EFFECT_FLIP_DISCARD and DXGI_ALPHA_MODE_IGNORE.
         //   As our swap chain won't have to compose with DWM anymore it reduces the display latency dramatically.
         desc.AlphaMode = _api.hwnd || _api.backgroundOpaqueMixin ? DXGI_ALPHA_MODE_IGNORE : DXGI_ALPHA_MODE_PREMULTIPLIED;
-        desc.Flags = DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT;
+        desc.Flags = debugGeneralPerformance ? 0 : DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT;
 
         wil::com_ptr<IDXGIFactory2> dxgiFactory;
         THROW_IF_FAILED(CreateDXGIFactory1(IID_PPV_ARGS(dxgiFactory.addressof())));
@@ -708,6 +713,7 @@ void AtlasEngine::_createSwapChain()
             THROW_IF_FAILED(dxgiFactory.query<IDXGIFactoryMedia>()->CreateSwapChainForCompositionSurfaceHandle(_r.device.get(), _api.swapChainHandle.get(), &desc, nullptr, _r.swapChain.put()));
         }
 
+        if constexpr (!debugGeneralPerformance)
         {
             const auto swapChain2 = _r.swapChain.query<IDXGISwapChain2>();
             _r.frameLatencyWaitableObject.reset(swapChain2->GetFrameLatencyWaitableObject());

src/renderer/atlas/AtlasEngine.h

@@ -903,7 +903,8 @@ namespace Microsoft::Console::Render
         void _drawCursor();
 
         static constexpr bool debugGlyphGenerationPerformance = false;
-        static constexpr bool debugGeneralPerformance = false || debugGlyphGenerationPerformance;
+        static constexpr bool debugTextParsingPerformance = false || debugGlyphGenerationPerformance;
+        static constexpr bool debugGeneralPerformance = false || debugTextParsingPerformance;
 
         static constexpr u16 u16min = 0x0000;
         static constexpr u16 u16max = 0xffff;