From 8ab8058cebbc77bda8af90a89818b91c140d0481 Mon Sep 17 00:00:00 2001
From: narzoul <narzoul@users.noreply.github.com>
Date: Sun, 6 Aug 2017 21:42:24 +0200
Subject: [PATCH] Fix reported memory caps of primary surface

Changed primary surface caps to report video memory in case the surface
was only forced into system memory by DDrawCompat.

Fixes startup issues in C&C 95 and Red Alert, reported in issue #3.
---
 DDrawCompat/DDraw/Surfaces/PrimarySurface.cpp     | 12 +++++++-----
 DDrawCompat/DDraw/Surfaces/PrimarySurface.h       |  2 +-
 DDrawCompat/DDraw/Surfaces/PrimarySurfaceImpl.cpp | 12 ++++++++++--
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/DDrawCompat/DDraw/Surfaces/PrimarySurface.cpp b/DDrawCompat/DDraw/Surfaces/PrimarySurface.cpp
index 8c62e2a..c37c62a 100644
--- a/DDrawCompat/DDraw/Surfaces/PrimarySurface.cpp
+++ b/DDrawCompat/DDraw/Surfaces/PrimarySurface.cpp
@@ -10,7 +10,7 @@ namespace
 	DDSURFACEDESC2 g_primarySurfaceDesc = {};
 	CompatWeakPtr<IDirectDrawSurface> g_gdiSurface = nullptr;
 	CompatWeakPtr<IDirectDrawSurface> g_primarySurface = nullptr;
-	bool g_isFlipEmulated = false;
+	DWORD g_origCaps = 0;
 }
 
 namespace DDraw
@@ -26,7 +26,7 @@ namespace DDraw
 
 		g_gdiSurface = nullptr;
 		g_primarySurface = nullptr;
-		g_isFlipEmulated = false;
+		g_origCaps = 0;
 		s_palette = nullptr;
 		s_surfaceBuffers.clear();
 		ZeroMemory(&s_paletteEntries, sizeof(s_paletteEntries));
@@ -46,6 +46,8 @@ namespace DDraw
 			return result;
 		}
 
+		const DWORD origCaps = desc.ddsCaps.dwCaps;
+
 		const auto& dm = DDraw::getDisplayMode(*CompatPtr<IDirectDraw7>::from(&dd));
 		desc.dwFlags |= DDSD_WIDTH | DDSD_HEIGHT | DDSD_PIXELFORMAT;
 		desc.dwWidth = dm.dwWidth;
@@ -69,7 +71,7 @@ namespace DDraw
 		CompatPtr<IDirectDrawSurface> surface1(Compat::queryInterface<IDirectDrawSurface>(surface));
 		g_gdiSurface = surface1;
 		g_primarySurface = surface1;
-		g_isFlipEmulated = 0 != (desc.ddsCaps.dwCaps & DDSCAPS_SYSTEMMEMORY);
+		g_origCaps = origCaps;
 
 		ZeroMemory(&g_primarySurfaceDesc, sizeof(g_primarySurfaceDesc));
 		g_primarySurfaceDesc.dwSize = sizeof(g_primarySurfaceDesc);
@@ -130,9 +132,9 @@ namespace DDraw
 			Compat::queryInterface<IDirectDrawSurface7>(g_primarySurface.get()));
 	}
 
-	bool PrimarySurface::isFlipEmulated()
+	DWORD PrimarySurface::getOrigCaps()
 	{
-		return g_isFlipEmulated;
+		return g_origCaps;
 	}
 
 	void PrimarySurface::resizeBuffers(CompatRef<IDirectDrawSurface7> surface)
diff --git a/DDrawCompat/DDraw/Surfaces/PrimarySurface.h b/DDrawCompat/DDraw/Surfaces/PrimarySurface.h
index 37478f0..0f7e82b 100644
--- a/DDrawCompat/DDraw/Surfaces/PrimarySurface.h
+++ b/DDrawCompat/DDraw/Surfaces/PrimarySurface.h
@@ -20,7 +20,7 @@ namespace DDraw
 		static const DDSURFACEDESC2& getDesc();
 		static CompatPtr<IDirectDrawSurface7> getGdiSurface();
 		static CompatPtr<IDirectDrawSurface7> getPrimary();
-		static bool isFlipEmulated();
+		static DWORD getOrigCaps();
 
 		void updateGdiSurfacePtr(IDirectDrawSurface* flipTargetOverride);
 
diff --git a/DDrawCompat/DDraw/Surfaces/PrimarySurfaceImpl.cpp b/DDrawCompat/DDraw/Surfaces/PrimarySurfaceImpl.cpp
index 59b1673..5dda0a8 100644
--- a/DDrawCompat/DDraw/Surfaces/PrimarySurfaceImpl.cpp
+++ b/DDrawCompat/DDraw/Surfaces/PrimarySurfaceImpl.cpp
@@ -10,6 +10,13 @@ namespace
 	{
 		caps &= ~DDSCAPS_OFFSCREENPLAIN;
 		caps |= DDSCAPS_PRIMARYSURFACE | DDSCAPS_VISIBLE;
+
+		if ((caps & DDSCAPS_SYSTEMMEMORY) &&
+			!(DDraw::PrimarySurface::getOrigCaps() & DDSCAPS_SYSTEMMEMORY))
+		{
+			caps &= ~DDSCAPS_SYSTEMMEMORY;
+			caps |= DDSCAPS_VIDEOMEMORY | DDSCAPS_LOCALVIDMEM;
+		}
 	}
 }
 
@@ -85,8 +92,9 @@ namespace DDraw
 			return result;
 		}
 
+		const bool isFlipEmulated = 0 != (PrimarySurface::getOrigCaps() & DDSCAPS_SYSTEMMEMORY);
 		result = RealPrimarySurface::flip(dwFlags);
-		if (SUCCEEDED(result) && !PrimarySurface::isFlipEmulated())
+		if (SUCCEEDED(result) && !isFlipEmulated)
 		{
 			static_cast<PrimarySurface*>(m_data)->updateGdiSurfacePtr(
 				CompatPtr<IDirectDrawSurface>::from(lpDDSurfaceTargetOverride));
@@ -95,7 +103,7 @@ namespace DDraw
 
 		undoFlip(This, lpDDSurfaceTargetOverride);
 
-		if (SUCCEEDED(result) && PrimarySurface::isFlipEmulated())
+		if (SUCCEEDED(result) && isFlipEmulated)
 		{
 			if (lpDDSurfaceTargetOverride)
 			{