Add engine param for enabling touch emulation during initialization.

Adjust sample base class to add screen joystick on desktop platform when touch emulation is enabled.

Docs/GettingStarted.dox

@@ -242,6 +242,7 @@ The engine can be configured using the following command line options.
 -nosound     Disable sound output
 -noip        Disable sound mixing interpolation
 -sm2         Force SM2.0 rendering
+-touch       Touch emulation on desktop platform
 \endverbatim
 
 \section Running_Xcode_AngelScript_Info Mac OS X specific - How to view/edit AngelScript within Xcode

Docs/Reference.dox

@@ -159,6 +159,7 @@ The full list of supported parameters, their datatypes and default values:
 - SoundMixRate (int) %Sound output frequency in Hz. Default 44100.
 - SoundStereo (bool) Stereo sound output mode. Default true.
 - SoundInterpolation (bool) Interpolated sound output mode to improve quality. Default true.
+- TouchEmulation (bool) %Touch emulation on desktop platform. Default false.
 
 \section MainLoop_Frame Main loop iteration
 

Source/Engine/Engine/Engine.cpp

@@ -359,6 +359,10 @@ bool Engine::Initialize(const VariantMap& parameters)
     // Init FPU state of main thread
     InitFPU();
 
+    // Initialize input
+    if (HasParameter(parameters, "TouchEmulation"))
+        GetSubsystem<Input>()->SetTouchEmulation(GetParameter(parameters, "TouchEmulation").GetBool());
+
     #ifdef URHO3D_TESTING
     if (HasParameter(parameters, "TimeOut"))
         timeOut_ = GetParameter(parameters, "TimeOut", 0).GetInt() * 1000000LL;
@@ -795,6 +799,8 @@ VariantMap Engine::ParseParameters(const Vector<String>& arguments)
                 ret["TextureAnisotropy"] = ToInt(value);
                 ++i;
             }
+            else if (argument == "touch")
+                ret["TouchEmulation"] = true;
             #ifdef URHO3D_TESTING
             else if (argument == "timeout" && !value.Empty())
             {

Source/Samples/Sample.h

@@ -94,6 +94,8 @@ private:
     void HandleKeyDown(StringHash eventType, VariantMap& eventData);
     /// Handle scene update event to control camera's pitch and yaw for all samples.
     void HandleSceneUpdate(StringHash eventType, VariantMap& eventData);
+    /// Handle touch begin event to initialize touch input on desktop platform.
+    void HandleTouchBegin(StringHash eventType, VariantMap& eventData);
 
     /// Screen joystick index for navigational controls (mobile platforms only).
     unsigned screenJoystickIndex_;

Source/Samples/Sample.inl

@@ -62,8 +62,12 @@ void Sample::Setup()
 
 void Sample::Start()
 {
-    // Initialize touch input on mobile platforms
-    InitTouchInput();
+    if (GetPlatform() == "Android" || GetPlatform() == "iOS")
+        // On mobile platform, enable touch by adding a screen joystick
+        InitTouchInput();
+    else if (GetSubsystem<Input>()->GetNumJoysticks() == 0)
+        // On desktop platform, do not detect touch when we already got a joystick
+        SubscribeToEvent(E_TOUCHBEGIN, HANDLER(Sample, HandleTouchBegin));
 
     // Create logo
     CreateLogo();
@@ -82,27 +86,24 @@ void Sample::Start()
 
 void Sample::InitTouchInput()
 {
-    if (GetPlatform() == "Android" || GetPlatform() == "iOS")
-    {
-        touchEnabled_ = true;
+    touchEnabled_ = true;
 
-        ResourceCache* cache = GetSubsystem<ResourceCache>();
-        Input* input = GetSubsystem<Input>();
-        XMLFile* layout = cache->GetResource<XMLFile>("UI/ScreenJoystick_Samples.xml");
-        const String& patchString = GetScreenJoystickPatchString();
-        if (!patchString.Empty())
-        {
-            // Patch the screen joystick layout further on demand
-            VectorBuffer buffer;
-            buffer.WriteString(patchString);
-            buffer.Seek(0);
-            SharedPtr<XMLFile> patchFile(new XMLFile(context_));
-            if (patchFile->Load(buffer))
-                layout->Patch(patchFile);
-        }
-        screenJoystickIndex_ = input->AddScreenJoystick(layout, cache->GetResource<XMLFile>("UI/DefaultStyle.xml"));
-        input->SetScreenJoystickVisible(screenJoystickSettingsIndex_, true);
+    ResourceCache* cache = GetSubsystem<ResourceCache>();
+    Input* input = GetSubsystem<Input>();
+    XMLFile* layout = cache->GetResource<XMLFile>("UI/ScreenJoystick_Samples.xml");
+    const String& patchString = GetScreenJoystickPatchString();
+    if (!patchString.Empty())
+    {
+        // Patch the screen joystick layout further on demand
+        VectorBuffer buffer;
+        buffer.WriteString(patchString);
+        buffer.Seek(0);
+        SharedPtr<XMLFile> patchFile(new XMLFile(context_));
+        if (patchFile->Load(buffer))
+            layout->Patch(patchFile);
     }
+    screenJoystickIndex_ = input->AddScreenJoystick(layout, cache->GetResource<XMLFile>("UI/DefaultStyle.xml"));
+    input->SetScreenJoystickVisible(screenJoystickSettingsIndex_, true);
 }
 
 void Sample::SetLogoVisible(bool enable)
@@ -326,3 +327,10 @@ void Sample::HandleSceneUpdate(StringHash eventType, VariantMap& eventData)
         }
     }
 }
+
+void Sample::HandleTouchBegin(StringHash eventType, VariantMap& eventData)
+{
+    // On some platforms like Windows the presence of touch input can only be detected dynamically
+    InitTouchInput();
+    UnsubscribeFromEvent("TouchBegin");
+}

Source/Tools/Urho3DPlayer/Urho3DPlayer.cpp

@@ -113,6 +113,7 @@ void Urho3DPlayer::Setup()
             "-nosound     Disable sound output\n"
             "-noip        Disable sound mixing interpolation\n"
             "-sm2         Force SM2.0 rendering\n"
+            "-touch       Touch emulation on desktop platform\n"
             #endif
         );
     }