ImGuiInputBinding.hpp

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#pragma once


#if WITH_IMGUI
#include <imgui.h>

#if FLING_WINDOWS

#undef APIENTRY
#define GLFW_EXPOSE_NATIVE_WIN32

#elif FLING_LINUX

#define GLFW_EXPOSE_NATIVE_X11

#endif

#include <GLFW/glfw3native.h>   // for glfwGetWin32Window

namespace Fling
{
    namespace InternalImGui
    {
        // Data
        enum GlfwClientApi
        {
            GlfwClientApi_Unknown,
            GlfwClientApi_OpenGL,
            GlfwClientApi_Vulkan
        };

        static GlfwClientApi        g_ClientApi = GlfwClientApi_Unknown;
        static bool                 g_MouseJustPressed[5] = { false, false, false, false, false };
        static bool                 g_InstalledCallbacks = false;

        // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
        static GLFWmousebuttonfun   g_PrevUserCallbackMousebutton = NULL;
        static GLFWscrollfun        g_PrevUserCallbackScroll = NULL;
        static GLFWkeyfun           g_PrevUserCallbackKey = NULL;
        static GLFWcharfun          g_PrevUserCallbackChar = NULL;

        static const char* ImGui_ImplGlfw_GetClipboardText(void* user_data)
        {
            return glfwGetClipboardString((GLFWwindow*)user_data);
        }

        static void ImGui_ImplGlfw_SetClipboardText(void* user_data, const char* text)
        {
            glfwSetClipboardString((GLFWwindow*)user_data, text);
        }

        void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
        {
            if (g_PrevUserCallbackMousebutton != NULL)
                g_PrevUserCallbackMousebutton(window, button, action, mods);

            if (action == GLFW_PRESS && button >= 0 && button < IM_ARRAYSIZE(g_MouseJustPressed))
                g_MouseJustPressed[button] = true;
        }

        void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
        {
            if (g_PrevUserCallbackScroll != NULL)
                g_PrevUserCallbackScroll(window, xoffset, yoffset);

            ImGuiIO& io = ImGui::GetIO();
            io.MouseWheelH += (float)xoffset;
            io.MouseWheel += (float)yoffset;
        }

        void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
        {
            if (g_PrevUserCallbackChar != NULL)
                g_PrevUserCallbackChar(window, c);

            ImGuiIO& io = ImGui::GetIO();
            io.AddInputCharacter(c);
        }

        void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
        {
            if (g_PrevUserCallbackKey != NULL)
                g_PrevUserCallbackKey(window, key, scancode, action, mods);

            ImGuiIO& io = ImGui::GetIO();
            if (action == GLFW_PRESS)
                io.KeysDown[key] = true;
            if (action == GLFW_RELEASE)
                io.KeysDown[key] = false;

            // Modifiers are not reliable across systems
            io.KeyCtrl = io.KeysDown[GLFW_KEY_LEFT_CONTROL] || io.KeysDown[GLFW_KEY_RIGHT_CONTROL];
            io.KeyShift = io.KeysDown[GLFW_KEY_LEFT_SHIFT] || io.KeysDown[GLFW_KEY_RIGHT_SHIFT];
            io.KeyAlt = io.KeysDown[GLFW_KEY_LEFT_ALT] || io.KeysDown[GLFW_KEY_RIGHT_ALT];
            io.KeySuper = io.KeysDown[GLFW_KEY_LEFT_SUPER] || io.KeysDown[GLFW_KEY_RIGHT_SUPER];
        }

        void SetImGuiCallbacks()
        {
            if (!ImGui::GetCurrentContext())
            {
                ImGui::CreateContext();
            }

            ImGuiIO& io = ImGui::GetIO();
            io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
            io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
            io.BackendPlatformName = "imgui_impl_glfw";

            io.KeyMap[ImGuiKey_Tab] = FL_KEYCODE_TAB;
            io.KeyMap[ImGuiKey_LeftArrow] = FL_KEYCODE_LEFT;
            io.KeyMap[ImGuiKey_RightArrow] = FL_KEYCODE_RIGHT;
            io.KeyMap[ImGuiKey_UpArrow] = FL_KEYCODE_UP;
            io.KeyMap[ImGuiKey_DownArrow] = FL_KEYCODE_DOWN;
            io.KeyMap[ImGuiKey_PageUp] = FL_KEYCODE_PAGE_UP;
            io.KeyMap[ImGuiKey_PageDown] = FL_KEYCODE_PAGE_DOWN;
            io.KeyMap[ImGuiKey_Home] = FL_KEYCODE_HOME;
            io.KeyMap[ImGuiKey_End] = FL_KEYCODE_END;
            io.KeyMap[ImGuiKey_Insert] = FL_KEYCODE_INSERT;
            io.KeyMap[ImGuiKey_Delete] = FL_KEYCODE_DELETE;
            io.KeyMap[ImGuiKey_Backspace] = FL_KEYCODE_BACKSPACE;
            io.KeyMap[ImGuiKey_Space] = FL_KEYCODE_SPACE;
            io.KeyMap[ImGuiKey_Enter] = FL_KEYCODE_ENTER;
            io.KeyMap[ImGuiKey_Escape] = FL_KEYCODE_ESCAPE;
            io.KeyMap[ImGuiKey_KeyPadEnter] = FL_KEYCODE_KP_ENTER;
            io.KeyMap[ImGuiKey_A] = FL_KEYCODE_A;
            io.KeyMap[ImGuiKey_C] = FL_KEYCODE_C;
            io.KeyMap[ImGuiKey_V] = FL_KEYCODE_V;
            io.KeyMap[ImGuiKey_X] = FL_KEYCODE_X;
            io.KeyMap[ImGuiKey_Y] = FL_KEYCODE_Y;
            io.KeyMap[ImGuiKey_Z] = FL_KEYCODE_Z;

            DesktopWindow* DesktopWin = static_cast<DesktopWindow*>(VulkanApp::Get().GetCurrentWindow());

            assert(DesktopWin);

            io.SetClipboardTextFn = ImGui_ImplGlfw_SetClipboardText;
            io.GetClipboardTextFn = ImGui_ImplGlfw_GetClipboardText;
            io.ClipboardUserData = DesktopWin;

#if FLING_WINDOWS
            io.ImeWindowHandle = (void*)glfwGetWin32Window(DesktopWin->GetGlfwWindow());
#elif FLING_LINUX
            io.ImeWindowHandle = (void*)glfwGetX11Window(DesktopWin->GetGlfwWindow());
#endif
            // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
            g_PrevUserCallbackMousebutton = nullptr;
            g_PrevUserCallbackScroll = nullptr;
            g_PrevUserCallbackKey = nullptr;
            g_PrevUserCallbackChar = nullptr;
            {
                GLFWwindow* Window = DesktopWin->GetGlfwWindow();
                g_InstalledCallbacks = true;
                g_PrevUserCallbackMousebutton = glfwSetMouseButtonCallback(Window, ImGui_ImplGlfw_MouseButtonCallback);
                g_PrevUserCallbackScroll = glfwSetScrollCallback(Window, ImGui_ImplGlfw_ScrollCallback);
                g_PrevUserCallbackKey = glfwSetKeyCallback(Window, ImGui_ImplGlfw_KeyCallback);
                g_PrevUserCallbackChar = glfwSetCharCallback(Window, ImGui_ImplGlfw_CharCallback);
            }
            g_ClientApi = GlfwClientApi_Vulkan;
        }
    }   // namespace InternalImGui
}   // namespace Fling
#endif