DDrawCompat/DDrawCompat/Gdi/Dc.cpp

#include <algorithm>
#include <unordered_map>
#include <vector>

#include "Common/Hook.h"
#include "Common/Log.h"
#include "DDraw/ScopedThreadLock.h"
#include "Gdi/Dc.h"
#include "Gdi/DcCache.h"
#include "Gdi/Gdi.h"
#include "Gdi/VirtualScreen.h"
#include "Gdi/Window.h"

namespace
{
	struct CompatDc
	{
		HDC dc;
		DWORD refCount;
		HDC origDc;
		DWORD threadId;
		int savedState;
	};

	typedef std::unordered_map<HDC, CompatDc> CompatDcMap;

	CompatDcMap g_origDcToCompatDc;

	void restoreDc(const CompatDc& compatDc);

	void copyDcAttributes(const CompatDc& compatDc, HDC origDc, const POINT& origin)
	{
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_FONT));
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_BRUSH));
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_PEN));

		if (GM_ADVANCED == GetGraphicsMode(origDc))
		{
			SetGraphicsMode(compatDc.dc, GM_ADVANCED);
			XFORM transform = {};
			GetWorldTransform(origDc, &transform);
			SetWorldTransform(compatDc.dc, &transform);
		}

		SetMapMode(compatDc.dc, GetMapMode(origDc));

		POINT viewportOrg = {};
		GetViewportOrgEx(origDc, &viewportOrg);
		SetViewportOrgEx(compatDc.dc, viewportOrg.x + origin.x, viewportOrg.y + origin.y, nullptr);
		SIZE viewportExt = {};
		GetViewportExtEx(origDc, &viewportExt);
		SetViewportExtEx(compatDc.dc, viewportExt.cx, viewportExt.cy, nullptr);

		POINT windowOrg = {};
		GetWindowOrgEx(origDc, &windowOrg);
		SetWindowOrgEx(compatDc.dc, windowOrg.x, windowOrg.y, nullptr);
		SIZE windowExt = {};
		GetWindowExtEx(origDc, &windowExt);
		SetWindowExtEx(compatDc.dc, windowExt.cx, windowExt.cy, nullptr);

		SetArcDirection(compatDc.dc, GetArcDirection(origDc));
		SetBkColor(compatDc.dc, GetBkColor(origDc));
		SetBkMode(compatDc.dc, GetBkMode(origDc));
		SetDCBrushColor(compatDc.dc, GetDCBrushColor(origDc));
		SetDCPenColor(compatDc.dc, GetDCPenColor(origDc));
		SetLayout(compatDc.dc, GetLayout(origDc));
		SetPolyFillMode(compatDc.dc, GetPolyFillMode(origDc));
		SetROP2(compatDc.dc, GetROP2(origDc));
		SetStretchBltMode(compatDc.dc, GetStretchBltMode(origDc));
		SetTextAlign(compatDc.dc, GetTextAlign(origDc));
		SetTextCharacterExtra(compatDc.dc, GetTextCharacterExtra(origDc));
		SetTextColor(compatDc.dc, GetTextColor(origDc));

		POINT brushOrg = {};
		GetBrushOrgEx(origDc, &brushOrg);
		SetBrushOrgEx(compatDc.dc, brushOrg.x, brushOrg.y, nullptr);

		POINT currentPos = {};
		GetCurrentPositionEx(origDc, &currentPos);
		MoveToEx(compatDc.dc, currentPos.x, currentPos.y, nullptr);
	}

	void restoreDc(const CompatDc& compatDc)
	{
		// Bitmap may have changed during VirtualScreen::update, do not let RestoreDC restore the old one
		HGDIOBJ bitmap = GetCurrentObject(compatDc.dc, OBJ_BITMAP);
		RestoreDC(compatDc.dc, compatDc.savedState);
		SelectObject(compatDc.dc, bitmap);
	}

	void setClippingRegion(HDC compatDc, HDC origDc, HWND hwnd, const POINT& origin)
	{
		if (hwnd)
		{
			HRGN sysRgn = CreateRectRgn(0, 0, 0, 0);
			if (1 == GetRandomRgn(origDc, sysRgn, SYSRGN))
			{
				SelectClipRgn(compatDc, sysRgn);
				SetMetaRgn(compatDc);
			}
			DeleteObject(sysRgn);
		}

		HRGN clipRgn = CreateRectRgn(0, 0, 0, 0);
		if (1 == GetClipRgn(origDc, clipRgn))
		{
			OffsetRgn(clipRgn, origin.x, origin.y);
			SelectClipRgn(compatDc, clipRgn);
		}
		DeleteObject(clipRgn);
	}
}

namespace Gdi
{
	namespace Dc
	{
		void dllProcessDetach()
		{
			DDraw::ScopedThreadLock lock;
			for (auto& origDcToCompatDc : g_origDcToCompatDc)
			{
				restoreDc(origDcToCompatDc.second);
				Gdi::DcCache::deleteDc(origDcToCompatDc.second.dc);
			}
			g_origDcToCompatDc.clear();
		}

		void dllThreadDetach()
		{
			DDraw::ScopedThreadLock lock;
			const DWORD threadId = GetCurrentThreadId();
			auto it = g_origDcToCompatDc.begin();
			while (it != g_origDcToCompatDc.end())
			{
				if (threadId == it->second.threadId)
				{
					restoreDc(it->second);
					Gdi::DcCache::deleteDc(it->second.dc);
					it = g_origDcToCompatDc.erase(it);
				}
				else
				{
					++it;
				}
			}
		}

		HDC getDc(HDC origDc)
		{
			if (!origDc || OBJ_DC != GetObjectType(origDc) || DT_RASDISPLAY != GetDeviceCaps(origDc, TECHNOLOGY))
			{
				return nullptr;
			}

			DDraw::ScopedThreadLock lock;
			auto it = g_origDcToCompatDc.find(origDc);
			if (it != g_origDcToCompatDc.end())
			{
				++it->second.refCount;
				return it->second.dc;
			}

			const HWND wnd = CALL_ORIG_FUNC(WindowFromDC)(origDc);
			auto rootWnd = wnd ? GetAncestor(wnd, GA_ROOT) : nullptr;
			if (rootWnd && GetDesktopWindow() != rootWnd)
			{
				auto rootWindow(Window::get(rootWnd));
				if (!rootWindow)
				{
					return nullptr;
				}
				rootWindow->updateWindow();
			}

			CompatDc compatDc;
			compatDc.dc = Gdi::DcCache::getDc();
			if (!compatDc.dc)
			{
				return nullptr;
			}

			POINT origin = {};
			GetDCOrgEx(origDc, &origin);
			RECT virtualScreenBounds = Gdi::VirtualScreen::getBounds();
			origin.x -= virtualScreenBounds.left;
			origin.y -= virtualScreenBounds.top;

			compatDc.savedState = SaveDC(compatDc.dc);
			copyDcAttributes(compatDc, origDc, origin);
			setClippingRegion(compatDc.dc, origDc, wnd, origin);

			compatDc.refCount = 1;
			compatDc.origDc = origDc;
			compatDc.threadId = GetCurrentThreadId();
			g_origDcToCompatDc.insert(CompatDcMap::value_type(origDc, compatDc));

			return compatDc.dc;
		}

		HDC getOrigDc(HDC dc)
		{
			DDraw::ScopedThreadLock lock;
			const auto it = std::find_if(g_origDcToCompatDc.begin(), g_origDcToCompatDc.end(),
				[dc](const CompatDcMap::value_type& compatDc) { return compatDc.second.dc == dc; });
			return it != g_origDcToCompatDc.end() ? it->first : dc;
		}

		void releaseDc(HDC origDc)
		{
			DDraw::ScopedThreadLock lock;
			auto it = g_origDcToCompatDc.find(origDc);
			if (it == g_origDcToCompatDc.end())
			{
				return;
			}

			CompatDc& compatDc = it->second;
			--compatDc.refCount;
			if (0 == compatDc.refCount)
			{
				restoreDc(compatDc);
				Gdi::DcCache::releaseDc(compatDc.dc);
				g_origDcToCompatDc.erase(origDc);
			}
		}
	}
}