Backends: SDL, Win32: Fixed inverted horizontal mouse wheel axis. (oc…

…ornut#4019)

backends/imgui_impl_sdl.cpp

@@ -11,13 +11,14 @@
 // Missing features:
 //  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
 
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
 // Read online: https://github.com/ocornut/imgui/tree/master/docs
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2021-06-01: Inputs: Fixed inverted horizontal mouse wheel axis. (#4019)
 //  2021-03-22: Rework global mouse pos availability check listing supported platforms explicitly, effectively fixing mouse access on Raspberry Pi. (#2837, #3950)
 //  2020-05-25: Misc: Report a zero display-size when window is minimized, to be consistent with other backends.
 //  2020-02-20: Inputs: Fixed mapping for ImGuiKey_KeyPadEnter (using SDL_SCANCODE_KP_ENTER instead of SDL_SCANCODE_RETURN2).
@@ -92,8 +93,8 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
     {
     case SDL_MOUSEWHEEL:
         {
-            if (event->wheel.x > 0) io.MouseWheelH += 1;
-            if (event->wheel.x < 0) io.MouseWheelH -= 1;
+            if (event->wheel.x > 0) io.MouseWheelH -= 1;
+            if (event->wheel.x < 0) io.MouseWheelH += 1;
             if (event->wheel.y > 0) io.MouseWheel += 1;
             if (event->wheel.y < 0) io.MouseWheel -= 1;
             return true;

backends/imgui_impl_win32.cpp

@@ -7,7 +7,7 @@
 //  [X] Platform: Keyboard arrays indexed using VK_* Virtual Key Codes, e.g. ImGui::IsKeyPressed(VK_SPACE).
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
 // Read online: https://github.com/ocornut/imgui/tree/master/docs
@@ -33,6 +33,7 @@ typedef DWORD (WINAPI *PFN_XInputGetState)(DWORD, XINPUT_STATE*);
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2021-06-01: Inputs: Fixed inverted horizontal mouse wheel axis. (#4019)
 //  2021-03-23: Inputs: Clearing keyboard down array when losing focus (WM_KILLFOCUS).
 //  2021-02-18: Added ImGui_ImplWin32_EnableAlphaCompositing(). Non Visual Studio users will need to link with dwmapi.lib (MinGW/gcc: use -ldwmapi).
 //  2021-02-17: Fixed ImGui_ImplWin32_EnableDpiAwareness() attempting to get SetProcessDpiAwareness from shcore.dll on Windows 8 whereas it is only supported on Windows 8.1.
@@ -363,7 +364,7 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
         io.MouseWheel += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
         return 0;
     case WM_MOUSEHWHEEL:
-        io.MouseWheelH += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
+        io.MouseWheelH -= (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
         return 0;
     case WM_KEYDOWN:
     case WM_SYSKEYDOWN:

docs/CHANGELOG.txt

@@ -42,6 +42,7 @@ Other Changes:
   Normally the right way to disable compiling the demo is to set IMGUI_DISABLE_DEMO_WINDOWS, but we want to avoid
   implying that the file is required.
 - Backends: OpenGL3: Handle GL_CLIP_ORIGIN on <4.5 contexts if "GL_ARB_clip_control" extension is detected. (#4170, #3998)
+- Backends: SDL, Win32: Fixed inverted horizontal mouse wheel axis. (#4019)
 
 
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