Comments, clarified use of io.MouseDelta (#942)

(ImGuiIO structure layout changed)

imgui.h

@@ -788,29 +788,29 @@ struct ImGuiIO
     ImWchar     InputCharacters[16+1];      // List of characters input (translated by user from keypress+keyboard state). Fill using AddInputCharacter() helper.
 
     // Functions
-    IMGUI_API void AddInputCharacter(ImWchar c);                        // Helper to add a new character into InputCharacters[]
-    IMGUI_API void AddInputCharactersUTF8(const char* utf8_chars);      // Helper to add new characters into InputCharacters[] from an UTF-8 string
-    inline void    ClearInputCharacters() { InputCharacters[0] = 0; }   // Helper to clear the text input buffer
+    IMGUI_API void AddInputCharacter(ImWchar c);                        // Add new character into InputCharacters[]
+    IMGUI_API void AddInputCharactersUTF8(const char* utf8_chars);      // Add new characters into InputCharacters[] from an UTF-8 string
+    inline void    ClearInputCharacters() { InputCharacters[0] = 0; }   // Clear the text input buffer manually
 
     //------------------------------------------------------------------
-    // Output - Retrieve after calling NewFrame(), you can use them to discard inputs or hide them from the rest of your application
+    // Output - Retrieve after calling NewFrame()
     //------------------------------------------------------------------
 
-    bool        WantCaptureMouse;           // Mouse is hovering a window or widget is active (= ImGui will use your mouse input)
-    bool        WantCaptureKeyboard;        // Widget is active (= ImGui will use your keyboard input)
-    bool        WantTextInput;              // Some text input widget is active, which will read input characters from the InputCharacters array.
-    float       Framerate;                  // Framerate estimation, in frame per second. Rolling average estimation based on IO.DeltaTime over 120 frames
+    bool        WantCaptureMouse;           // Mouse is hovering a window or widget is active (= ImGui will use your mouse input). Use to hide mouse from the rest of your application
+    bool        WantCaptureKeyboard;        // Widget is active (= ImGui will use your keyboard input). Use to hide keyboard from the rest of your application
+    bool        WantTextInput;              // Some text input widget is active, which will read input characters from the InputCharacters array. Use to activate on screen keyboard if your system needs one
+    float       Framerate;                  // Application framerate estimation, in frame per second. Solely for convenience. Rolling average estimation based on IO.DeltaTime over 120 frames
     int         MetricsAllocs;              // Number of active memory allocations
     int         MetricsRenderVertices;      // Vertices output during last call to Render()
     int         MetricsRenderIndices;       // Indices output during last call to Render() = number of triangles * 3
-    int         MetricsActiveWindows;       // Number of visible windows (exclude child windows)
+    int         MetricsActiveWindows;       // Number of visible root windows (exclude child windows)
+    ImVec2      MouseDelta;                 // Mouse delta. Note that this is zero if either current or previous position are negative, so a disappearing/reappearing mouse won't have a huge delta for one frame.
 
     //------------------------------------------------------------------
     // [Private] ImGui will maintain those fields. Forward compatibility not guaranteed!
     //------------------------------------------------------------------
 
-    ImVec2      MousePosPrev;               // Previous mouse position
-    ImVec2      MouseDelta;                 // Mouse delta. Note that this is zero if either current or previous position are negative to allow mouse enabling/disabling.
+    ImVec2      MousePosPrev;               // Previous mouse position temporary storage (nb: not for public use, set to MousePos in NewFrame())
     bool        MouseClicked[5];            // Mouse button went from !Down to Down
     ImVec2      MouseClickedPos[5];         // Position at time of clicking
     float       MouseClickedTime[5];        // Time of last click (used to figure out double-click)