Use SDL system cursors in SDL examples. (#1626)

(Squashed 4 commits)

examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp

@@ -43,6 +43,7 @@
 static Uint64       g_Time = 0;
 static bool         g_MousePressed[3] = { false, false, false };
 static GLuint       g_FontTexture = 0;
+static SDL_Cursor  *g_SdlCursorMap[ImGuiMouseCursor_Count_];
 
 // OpenGL2 Render function.
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
@@ -250,6 +251,14 @@ bool    ImGui_ImplSdlGL2_Init(SDL_Window* window)
     io.GetClipboardTextFn = ImGui_ImplSdlGL2_GetClipboardText;
     io.ClipboardUserData = NULL;
 
+    g_SdlCursorMap[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
+    g_SdlCursorMap[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
+    g_SdlCursorMap[ImGuiMouseCursor_Move] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNS] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENS);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeEW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEWE);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNESW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENESW);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNWSE] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENWSE);
+
 #ifdef _WIN32
     SDL_SysWMinfo wmInfo;
     SDL_VERSION(&wmInfo.version);
@@ -265,6 +274,9 @@ bool    ImGui_ImplSdlGL2_Init(SDL_Window* window)
 void ImGui_ImplSdlGL2_Shutdown()
 {
     ImGui_ImplSdlGL2_InvalidateDeviceObjects();
+
+    for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_Count_; cursor_n++)
+        SDL_FreeCursor(g_SdlCursorMap[cursor_n]);
 }
 
 void ImGui_ImplSdlGL2_NewFrame(SDL_Window *window)
@@ -314,7 +326,14 @@ void ImGui_ImplSdlGL2_NewFrame(SDL_Window *window)
 #endif
 
     // Hide OS mouse cursor if ImGui is drawing it
-    SDL_ShowCursor(io.MouseDrawCursor ? 0 : 1);
+    if (io.MouseDrawCursor)
+        SDL_ShowCursor(0);
+    else
+    {
+        SDL_Cursor *cursor = g_SdlCursorMap[ImGui::GetMouseCursor()];
+        SDL_SetCursor(cursor);
+        SDL_ShowCursor(1);
+    }
 
     // Start the frame. This call will update the io.WantCaptureMouse, io.WantCaptureKeyboard flag that you can use to dispatch inputs (or not) to your application.
     ImGui::NewFrame();

examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

@@ -45,6 +45,7 @@ static int          g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
 static int          g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
 static int          g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
 static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
+static SDL_Cursor  *g_SdlCursorMap[ImGuiMouseCursor_Count_];
 
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so. 
@@ -364,6 +365,14 @@ bool    ImGui_ImplSdlGL3_Init(SDL_Window* window)
     io.GetClipboardTextFn = ImGui_ImplSdlGL3_GetClipboardText;
     io.ClipboardUserData = NULL;
 
+    g_SdlCursorMap[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
+    g_SdlCursorMap[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
+    g_SdlCursorMap[ImGuiMouseCursor_Move] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNS] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENS);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeEW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEWE);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNESW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENESW);
+    g_SdlCursorMap[ImGuiMouseCursor_ResizeNWSE] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENWSE);
+
 #ifdef _WIN32
     SDL_SysWMinfo wmInfo;
     SDL_VERSION(&wmInfo.version);
@@ -379,6 +388,9 @@ bool    ImGui_ImplSdlGL3_Init(SDL_Window* window)
 void ImGui_ImplSdlGL3_Shutdown()
 {
     ImGui_ImplSdlGL3_InvalidateDeviceObjects();
+
+    for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_Count_; cursor_n++)
+        SDL_FreeCursor(g_SdlCursorMap[cursor_n]);
 }
 
 void ImGui_ImplSdlGL3_NewFrame(SDL_Window* window)
@@ -428,7 +440,14 @@ void ImGui_ImplSdlGL3_NewFrame(SDL_Window* window)
 #endif
 
     // Hide OS mouse cursor if ImGui is drawing it
-    SDL_ShowCursor(io.MouseDrawCursor ? 0 : 1);
+    if (io.MouseDrawCursor)
+        SDL_ShowCursor(0);
+    else
+    {
+        SDL_Cursor *cursor = g_SdlCursorMap[ImGui::GetMouseCursor()];
+        SDL_SetCursor(cursor);
+        SDL_ShowCursor(1);
+    }
 
     // Start the frame. This call will update the io.WantCaptureMouse, io.WantCaptureKeyboard flag that you can use to dispatch inputs (or not) to your application.
     ImGui::NewFrame();