Removed IMGUI_ONCE_UPON_A_FRAME in favor of ImGuiOnceUponAFrame which is supported by all compilers

imgui.cpp

@@ -142,7 +142,7 @@
       e.g. "##Foobar" display an empty label and uses "##Foobar" as ID
    - read articles about the imgui principles (see web links) to understand the requirement and use of ID.
 
- - tip: the construct 'if (IMGUI_ONCE_UPON_A_FRAME)' will evaluate to true only once a frame, you can use it to add custom UI in the middle of a deep nested inner loop in your code.
+ - tip: the construct 'static ImGuiOnceUponAFrame once; if (once)' will evaluate to 'true' only once a frame, you can use it to quickly add custom UI in the middle of a deep nested inner loop in your code.
  - tip: you can call Render() multiple times (e.g for VR renders), up to you to communicate the extra state to your RenderDrawListFn function.
  - tip: you can create widgets without a Begin()/End() block, they will go in an implicit window called "Debug"
  - tip: read the ShowTestWindow() code for more example of how to use ImGui!
@@ -3675,7 +3675,7 @@ bool ImGui::SliderFloat(const char* label, float* v, float v_min, float v_max, c
     ItemSize(bb);
     RenderFrame(frame_bb.Min, frame_bb.Max, window->Color(ImGuiCol_FrameBg));
 
-	// Process clicking on the slider
+    // Process clicking on the slider
     if (g.ActiveId == id)
     {
         if (g.IO.MouseDown[0])
@@ -4428,17 +4428,17 @@ bool ImGui::InputText(const char* label, char* buf, size_t buf_size, ImGuiInputT
              edit_state.SelectedAllMouseLock = false;
 
         const int k_mask = (is_shift_down ? STB_TEXTEDIT_K_SHIFT : 0);
-		if (IsKeyPressedMap(ImGuiKey_LeftArrow))                { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_WORDLEFT | k_mask : STB_TEXTEDIT_K_LEFT | k_mask); }
+        if (IsKeyPressedMap(ImGuiKey_LeftArrow))                { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_WORDLEFT | k_mask : STB_TEXTEDIT_K_LEFT | k_mask); }
-		else if (IsKeyPressedMap(ImGuiKey_RightArrow))          { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_WORDRIGHT | k_mask  : STB_TEXTEDIT_K_RIGHT | k_mask); }
+        else if (IsKeyPressedMap(ImGuiKey_RightArrow))          { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_WORDRIGHT | k_mask  : STB_TEXTEDIT_K_RIGHT | k_mask); }
-		else if (IsKeyPressedMap(ImGuiKey_Home))                { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_TEXTSTART | k_mask : STB_TEXTEDIT_K_LINESTART | k_mask); }
+        else if (IsKeyPressedMap(ImGuiKey_Home))                { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_TEXTSTART | k_mask : STB_TEXTEDIT_K_LINESTART | k_mask); }
-		else if (IsKeyPressedMap(ImGuiKey_End))                 { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_TEXTEND | k_mask : STB_TEXTEDIT_K_LINEEND | k_mask); }
+        else if (IsKeyPressedMap(ImGuiKey_End))                 { edit_state.OnKeyPressed(is_ctrl_down ? STB_TEXTEDIT_K_TEXTEND | k_mask : STB_TEXTEDIT_K_LINEEND | k_mask); }
-		else if (IsKeyPressedMap(ImGuiKey_Delete))              { edit_state.OnKeyPressed(STB_TEXTEDIT_K_DELETE | k_mask); }
+        else if (IsKeyPressedMap(ImGuiKey_Delete))              { edit_state.OnKeyPressed(STB_TEXTEDIT_K_DELETE | k_mask); }
-		else if (IsKeyPressedMap(ImGuiKey_Backspace))           { edit_state.OnKeyPressed(STB_TEXTEDIT_K_BACKSPACE | k_mask); }
+        else if (IsKeyPressedMap(ImGuiKey_Backspace))           { edit_state.OnKeyPressed(STB_TEXTEDIT_K_BACKSPACE | k_mask); }
         else if (IsKeyPressedMap(ImGuiKey_Enter))               { g.ActiveId = 0; enter_pressed = true; }
         else if (IsKeyPressedMap(ImGuiKey_Escape))              { g.ActiveId = 0; cancel_edit = true; }
-		else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_Z))   { edit_state.OnKeyPressed(STB_TEXTEDIT_K_UNDO); }
+        else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_Z))   { edit_state.OnKeyPressed(STB_TEXTEDIT_K_UNDO); }
-		else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_Y))   { edit_state.OnKeyPressed(STB_TEXTEDIT_K_REDO); }
+        else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_Y))   { edit_state.OnKeyPressed(STB_TEXTEDIT_K_REDO); }
-		else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_A))   { edit_state.SelectAll(); }
+        else if (is_ctrl_down && IsKeyPressedMap(ImGuiKey_A))   { edit_state.SelectAll(); }
         else if (is_ctrl_down && (IsKeyPressedMap(ImGuiKey_X) || IsKeyPressedMap(ImGuiKey_C)))
         {
             // Cut, Copy
@@ -4550,15 +4550,15 @@ bool ImGui::InputText(const char* label, char* buf, size_t buf_size, ImGuiInputT
                     callback_data.BufSize = edit_state.BufSize;
                     callback_data.BufDirty = false;
                     callback_data.Flags = flags;
-					callback_data.UserData = user_data;
+                    callback_data.UserData = user_data;
 
                     // We have to convert from position from wchar to UTF-8 positions
                     const int utf8_cursor_pos = callback_data.CursorPos = ImTextCountUtf8BytesFromWchar(edit_state.Text, edit_state.Text + edit_state.StbState.cursor);
                     const int utf8_selection_start = callback_data.SelectionStart = ImTextCountUtf8BytesFromWchar(edit_state.Text, edit_state.Text + edit_state.StbState.select_start);
                     const int utf8_selection_end = callback_data.SelectionEnd = ImTextCountUtf8BytesFromWchar(edit_state.Text, edit_state.Text + edit_state.StbState.select_end);
 
-					// Call user code
+                    // Call user code
-					callback(&callback_data);
+                    callback(&callback_data);
 
                     // Read back what user may have modified
                     IM_ASSERT(callback_data.Buf == text_tmp_utf8);             // Invalid to modify those fields
@@ -6674,6 +6674,10 @@ void ImGui::ShowTestWindow(bool* open)
             ImGui::EndTooltip();
         }
 
+		//static ImGuiOnceUponAFrame oaf;
+		//if (oaf) ImGui::Text("This will be displayed.");
+		//if (oaf) ImGui::Text("This won't be displayed!");
+
         ImGui::Separator();
         ImGui::Text("^ Horizontal separator");
 
@@ -7083,7 +7087,7 @@ struct ExampleAppConsole
 
     void	TextEditCallback(ImGuiTextEditCallbackData* data)
     {
-		//AddLog("cursor: %d, selection: %d-%d", data->CursorPos, data->SelectionStart, data->SelectionEnd);
+        //AddLog("cursor: %d, selection: %d-%d", data->CursorPos, data->SelectionStart, data->SelectionEnd);
         switch (data->EventKey)
         {
         case ImGuiKey_Tab:
@@ -7140,11 +7144,11 @@ struct ExampleAppConsole
                         match_len++;
                     }
 
-					if (match_len > 0)
+                    if (match_len > 0)
-					{
+                    {
-						data->DeleteChars(word_start - data->Buf, word_end-word_start);
+                        data->DeleteChars(word_start - data->Buf, word_end-word_start);
-						data->InsertChars(data->CursorPos, candidates[0], candidates[0] + match_len);
+                        data->InsertChars(data->CursorPos, candidates[0], candidates[0] + match_len);
-					}
+                    }
 
                     // List matches
                     AddLog("Possible matches:\n");
@@ -7173,7 +7177,7 @@ static void ShowExampleAppConsole(bool* open)
     }
 
     ImGui::TextWrapped("This example implement a simple console. A more elaborate implementation may want to store individual entries along with extra data such as timestamp, emitter, etc.");
-	ImGui::TextWrapped("Press TAB to use text completion.");
+    ImGui::TextWrapped("Press TAB to use text completion.");
 
     // TODO: display from bottom
     // TODO: clip manually

imgui.h

@@ -123,7 +123,7 @@ public:
 #endif // #ifndef ImVector
 
 // Helpers at bottom of the file:
-// - if (IMGUI_ONCE_UPON_A_FRAME)       // Execute a block of code once per frame only
+// - struct ImGuiOnceUponAFrame         // Execute a block of code once per frame only (convenient for creating UI within deep-nested code that runs multiple times)
 // - struct ImGuiTextFilter             // Parse and apply text filters. In format "aaaaa[,bbbb][,ccccc]"
 // - struct ImGuiTextBuffer             // Text buffer for logging/accumulating text
 // - struct ImGuiStorage                // Custom key value storage (if you need to alter open/close states manually)
@@ -239,7 +239,7 @@ namespace ImGui
     IMGUI_API bool          CheckboxFlags(const char* label, unsigned int* flags, unsigned int flags_value);
     IMGUI_API bool          RadioButton(const char* label, bool active);
     IMGUI_API bool          RadioButton(const char* label, int* v, int v_button);
-	IMGUI_API bool          InputText(const char* label, char* buf, size_t buf_size, ImGuiInputTextFlags flags = 0, void (*callback)(ImGuiTextEditCallbackData*) = NULL, void* user_data = NULL);
+    IMGUI_API bool          InputText(const char* label, char* buf, size_t buf_size, ImGuiInputTextFlags flags = 0, void (*callback)(ImGuiTextEditCallbackData*) = NULL, void* user_data = NULL);
     IMGUI_API bool          InputFloat(const char* label, float* v, float step = 0.0f, float step_fast = 0.0f, int decimal_precision = -1, ImGuiInputTextFlags extra_flags = 0);
     IMGUI_API bool          InputFloat2(const char* label, float v[2], int decimal_precision = -1);
     IMGUI_API bool          InputFloat3(const char* label, float v[3], int decimal_precision = -1);
@@ -326,8 +326,8 @@ enum ImGuiInputTextFlags_
     ImGuiInputTextFlags_AutoSelectAll       = 1 << 2,   // Select entire text when first taking focus
     ImGuiInputTextFlags_EnterReturnsTrue    = 1 << 3,   // Return 'true' when Enter is pressed (as opposed to when the value was modified)
     ImGuiInputTextFlags_CallbackCompletion  = 1 << 4,   // Call user function on pressing TAB (for completion handling)
-	ImGuiInputTextFlags_CallbackHistory     = 1 << 5,   // Call user function on pressing Up/Down arrows (for history handling)
+    ImGuiInputTextFlags_CallbackHistory     = 1 << 5,   // Call user function on pressing Up/Down arrows (for history handling)
-	ImGuiInputTextFlags_CallbackAlways      = 1 << 6    // Call user function every frame
+    ImGuiInputTextFlags_CallbackAlways      = 1 << 6    // Call user function every frame
     //ImGuiInputTextFlags_AlignCenter       = 1 << 6,
 };
 
@@ -529,15 +529,15 @@ struct ImGuiIO
 //-----------------------------------------------------------------------------
 
 // Helper: execute a block of code once a frame only
-// Usage: if (IMGUI_ONCE_UPON_A_FRAME) {/*do something once a frame*/)
+// Convenient if you want to quickly create an UI within deep-nested code that runs multiple times every frame.
-#define IMGUI_ONCE_UPON_A_FRAME         static ImGuiOncePerFrame im = ImGuiOncePerFrame()
+// Usage: 
-struct ImGuiOncePerFrame
+//   static ImGuiOnceUponAFrame once;
+//   if (once) { ... }
+struct ImGuiOnceUponAFrame
 {
-    ImGuiOncePerFrame() : LastFrame(-1) {}
+    ImGuiOnceUponAFrame() { RefFrame = -1; }
-    operator bool() const { return TryIsNewFrame(); }
+    mutable int RefFrame;
-private:
+    operator bool() const {	const int current_frame = ImGui::GetFrameCount(); if (RefFrame == current_frame) return false; RefFrame = current_frame; return true; }
-    mutable int LastFrame;
-    bool        TryIsNewFrame() const   { const int current_frame = ImGui::GetFrameCount(); if (LastFrame == current_frame) return false; LastFrame = current_frame; return true; }
 };
 
 // Helper: Parse and apply text filters. In format "aaaaa[,bbbb][,ccccc]"
@@ -608,19 +608,19 @@ struct ImGuiStorage
 // Shared state of InputText(), passed to callback when a ImGuiInputTextFlags_Callback* flag is used.
 struct ImGuiTextEditCallbackData
 {
-	ImGuiKey            EventKey;       // Key pressed (Up/Down/TAB)		// Read-only	
+    ImGuiKey            EventKey;       // Key pressed (Up/Down/TAB)		// Read-only	
-	char*			    Buf;            // Current text              		// Read-write (pointed data only)
+    char*			    Buf;            // Current text              		// Read-write (pointed data only)
-	size_t				BufSize;		//									// Read-only
+    size_t				BufSize;		//									// Read-only
-	bool				BufDirty;       // Set if you modify Buf directly   // Write
+    bool				BufDirty;       // Set if you modify Buf directly   // Write
-	ImGuiInputTextFlags	Flags;			// What user passed to InputText()	// Read-only
+    ImGuiInputTextFlags	Flags;			// What user passed to InputText()	// Read-only
-	int					CursorPos;		//									// Read-write
+    int					CursorPos;		//									// Read-write
-	int					SelectionStart; //									// Read-write (== to SelectionEnd when no selection)
+    int					SelectionStart; //									// Read-write (== to SelectionEnd when no selection)
-	int                 SelectionEnd;   //									// Read-write
+    int                 SelectionEnd;   //									// Read-write
-	void*               UserData;		// What user passed to InputText()
+    void*               UserData;		// What user passed to InputText()
 
-	// NB: calling those function loses selection.
+    // NB: calling those function loses selection.
-	void DeleteChars(size_t pos, size_t bytes_count);
+    void DeleteChars(size_t pos, size_t bytes_count);
-	void InsertChars(size_t pos, const char* text, const char* text_end = NULL);
+    void InsertChars(size_t pos, const char* text, const char* text_end = NULL);
 };
 
 //-----------------------------------------------------------------------------