Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_win32.cpp
#	imgui.cpp
#	imgui.h
#	imgui_demo.cpp
#	imgui_internal.h

backends/imgui_impl_allegro5.cpp

@@ -335,8 +335,9 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
 
 void ImGui_ImplAllegro5_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplAllegro5_InvalidateDeviceObjects();
     if (bd->VertexDecl)

backends/imgui_impl_dx10.cpp

@@ -565,8 +565,9 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
 
 void ImGui_ImplDX10_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX10_ShutdownPlatformInterface();
     ImGui_ImplDX10_InvalidateDeviceObjects();

backends/imgui_impl_dx11.cpp

@@ -581,8 +581,9 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
 
 void ImGui_ImplDX11_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX11_ShutdownPlatformInterface();
     ImGui_ImplDX11_InvalidateDeviceObjects();

backends/imgui_impl_dx12.cpp

@@ -799,8 +799,9 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
 
 void ImGui_ImplDX12_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     // Manually delete main viewport render resources in-case we haven't initialized for viewports
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();

backends/imgui_impl_dx9.cpp

@@ -312,8 +312,9 @@ bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
 
 void ImGui_ImplDX9_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX9_ShutdownPlatformInterface();
     ImGui_ImplDX9_InvalidateDeviceObjects();

backends/imgui_impl_glfw.cpp

@@ -351,8 +351,9 @@ bool ImGui_ImplGlfw_InitForOther(GLFWwindow* window, bool install_callbacks)
 
 void ImGui_ImplGlfw_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplGlfw_ShutdownPlatformInterface();
 

backends/imgui_impl_opengl2.cpp

@@ -96,8 +96,9 @@ bool    ImGui_ImplOpenGL2_Init()
 
 void    ImGui_ImplOpenGL2_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplOpenGL2_ShutdownPlatformInterface();
     ImGui_ImplOpenGL2_DestroyDeviceObjects();

backends/imgui_impl_opengl3.cpp

@@ -279,8 +279,9 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 
 void    ImGui_ImplOpenGL3_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplOpenGL3_ShutdownPlatformInterface();
     ImGui_ImplOpenGL3_DestroyDeviceObjects();

backends/imgui_impl_osx.mm

@@ -17,9 +17,11 @@
 #include "imgui.h"
 #include "imgui_impl_osx.h"
 #import <Cocoa/Cocoa.h>
+#include <mach/mach_time.h>
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2021-09-21: Use mach_absolute_time as CFAbsoluteTimeGetCurrent can jump backwards.
 //  2021-08-17: Calling io.AddFocusEvent() on NSApplicationDidBecomeActiveNotification/NSApplicationDidResignActiveNotification events.
 //  2021-06-23: Inputs: Added a fix for shortcuts using CTRL key instead of CMD key.
 //  2021-04-19: Inputs: Added a fix for keys remaining stuck in pressed state when CMD-tabbing into different application.
@@ -38,7 +40,8 @@
 @class ImFocusObserver;
 
 // Data
-static CFAbsoluteTime g_Time = 0.0;
+static double         g_HostClockPeriod = 0.0;
+static double         g_Time = 0.0;
 static NSCursor*      g_MouseCursors[ImGuiMouseCursor_COUNT] = {};
 static bool           g_MouseCursorHidden = false;
 static bool           g_MouseJustPressed[ImGuiMouseButton_COUNT] = {};
@@ -53,6 +56,18 @@ static ImFocusObserver* g_FocusObserver = NULL;
 + (id)_windowResizeEastWestCursor;
 @end
 
+static void InitHostClockPeriod()
+{
+    struct mach_timebase_info info;
+    mach_timebase_info(&info);
+    g_HostClockPeriod = 1e-9 * ((double)info.denom / (double)info.numer); // Period is the reciprocal of frequency.
+}
+
+static double GetMachAbsoluteTimeInSeconds()
+{
+    return (double)mach_absolute_time() * g_HostClockPeriod;
+}
+
 static void resetKeys()
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -233,8 +248,11 @@ void ImGui_ImplOSX_NewFrame(NSView* view)
 
     // Setup time step
     if (g_Time == 0.0)
-        g_Time = CFAbsoluteTimeGetCurrent();
-    CFAbsoluteTime current_time = CFAbsoluteTimeGetCurrent();
+    {
+        InitHostClockPeriod();
+        g_Time = GetMachAbsoluteTimeInSeconds();
+    }
+    double current_time = GetMachAbsoluteTimeInSeconds();
     io.DeltaTime = (float)(current_time - g_Time);
     g_Time = current_time;
 

backends/imgui_impl_sdl.cpp

@@ -320,10 +320,16 @@ bool ImGui_ImplSDL2_InitForMetal(SDL_Window* window)
     return ImGui_ImplSDL2_Init(window, NULL);
 }
 
+bool ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window)
+{
+    return ImGui_ImplSDL2_Init(window, NULL);
+}
+
 void ImGui_ImplSDL2_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplSDL2_ShutdownPlatformInterface();
 

backends/imgui_impl_sdl.h

@@ -27,6 +27,7 @@ IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* s
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForVulkan(SDL_Window* window);
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForD3D(SDL_Window* window);
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForMetal(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window);
 IMGUI_IMPL_API void     ImGui_ImplSDL2_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDL2_NewFrame();
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event);

backends/imgui_impl_sdlrenderer.cpp

@@ -0,0 +1,222 @@
+// dear imgui: Renderer Backend for SDL_Renderer
+// (Requires: SDL 2.0.17+)
+
+// Important to understand: SDL_Renderer is an _optional_ component of SDL. We do not recommend you use SDL_Renderer
+// because it provide a rather limited API to the end-user. We provide this backend for the sake of completeness.
+// For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+// Missing features:
+//  [ ] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
+
+// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// 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
+//  2021-09-21: Initial version.
+
+#include "imgui.h"
+#include "imgui_impl_sdlrenderer.h"
+#if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
+#include <stddef.h>     // intptr_t
+#else
+#include <stdint.h>     // intptr_t
+#endif
+
+// SDL
+#include <SDL.h>
+#if !SDL_VERSION_ATLEAST(2,0,17)
+#error This backend requires SDL 2.0.17+ because of SDL_RenderGeometry() function
+#endif
+
+// SDL_Renderer data
+struct ImGui_ImplSDLRenderer_Data
+{
+    SDL_Renderer*   SDLRenderer;
+    SDL_Texture*    FontTexture;
+    ImGui_ImplSDLRenderer_Data() { memset(this, 0, sizeof(*this)); }
+};
+
+// Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
+// It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
+static ImGui_ImplSDLRenderer_Data* ImGui_ImplSDLRenderer_GetBackendData()
+{
+    return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer_Data*)ImGui::GetIO().BackendRendererUserData : NULL;
+}
+
+// Functions
+bool ImGui_ImplSDLRenderer_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != NULL && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer_Data* bd = IM_NEW(ImGui_ImplSDLRenderer_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer";
+
+    bd->SDLRenderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer_Shutdown()
+{
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+
+    ImGui_ImplSDLRenderer_DestroyDeviceObjects();
+
+    io.BackendRendererName = NULL;
+    io.BackendRendererUserData = NULL;
+    IM_DELETE(bd);
+}
+
+static void ImGui_ImplSDLRenderer_SetupRenderState()
+{
+	ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+	// Clear out any viewports and cliprect set by the user
+    // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
+	SDL_RenderSetViewport(bd->SDLRenderer, NULL);
+	SDL_RenderSetClipRect(bd->SDLRenderer, NULL);
+}
+
+void ImGui_ImplSDLRenderer_NewFrame()
+{
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    IM_ASSERT(bd != NULL && "Did you call ImGui_ImplSDLRenderer_Init()?");
+
+    if (!bd->FontTexture)
+        ImGui_ImplSDLRenderer_CreateDeviceObjects();
+}
+
+void ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data)
+{
+	ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+	// If there's a scale factor set by the user, use that instead
+    // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
+    // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
+    float rsx = 1.0f;
+	float rsy = 1.0f;
+	SDL_RenderGetScale(bd->SDLRenderer, &rsx, &rsy);
+    ImVec2 render_scale;
+	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
+	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;
+
+	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+	int fb_width = (int)(draw_data->DisplaySize.x * render_scale.x);
+	int fb_height = (int)(draw_data->DisplaySize.y * render_scale.y);
+	if (fb_width == 0 || fb_height == 0)
+		return;
+
+	// Will project scissor/clipping rectangles into framebuffer space
+	ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
+	ImVec2 clip_scale = render_scale;
+
+    // Render command lists
+    ImGui_ImplSDLRenderer_SetupRenderState();
+    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    {
+        const ImDrawList* cmd_list = draw_data->CmdLists[n];
+        const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
+        const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
+
+        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
+        {
+            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
+            if (pcmd->UserCallback)
+            {
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplSDLRenderer_SetupRenderState();
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
+            }
+            else
+            {
+                // Project scissor/clipping rectangles into framebuffer space
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
+                if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
+                if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
+                if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; }
+                if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; }
+                if (clip_max.x < clip_min.x || clip_max.y < clip_min.y)
+                    continue;
+
+                SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
+                SDL_RenderSetClipRect(bd->SDLRenderer, &r);
+
+                const float* xy = (const float*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos));
+                const float* uv = (const float*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv));
+                const int* color = (const int*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col));
+
+                // Bind texture, Draw
+				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
+                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
+                    xy, (int)sizeof(ImDrawVert),
+                    color, (int)sizeof(ImDrawVert),
+                    uv, (int)sizeof(ImDrawVert),
+                    cmd_list->VtxBuffer.Size,
+                    idx_buffer + pcmd->IdxOffset, pcmd->ElemCount, sizeof(ImDrawIdx));
+            }
+        }
+    }
+}
+
+// Called by Init/NewFrame/Shutdown
+bool ImGui_ImplSDLRenderer_CreateFontsTexture()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+    // Build texture atlas
+    unsigned char* pixels;
+    int width, height;
+    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
+
+    // Upload texture to graphics system
+    bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, width, height);
+    if (bd->FontTexture == NULL)
+    {
+        SDL_Log("error creating texture");
+        return false;
+    }
+    SDL_UpdateTexture(bd->FontTexture, NULL, pixels, 4 * width);
+    SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
+
+    // Store our identifier
+    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer_DestroyFontsTexture()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    if (bd->FontTexture)
+    {
+        io.Fonts->SetTexID(0);
+        SDL_DestroyTexture(bd->FontTexture);
+        bd->FontTexture = NULL;
+    }
+}
+
+bool ImGui_ImplSDLRenderer_CreateDeviceObjects()
+{
+    return ImGui_ImplSDLRenderer_CreateFontsTexture();
+}
+
+void ImGui_ImplSDLRenderer_DestroyDeviceObjects()
+{
+    ImGui_ImplSDLRenderer_DestroyFontsTexture();
+}

backends/imgui_impl_sdlrenderer.h

@@ -0,0 +1,28 @@
+// dear imgui: Renderer Backend for SDL_Renderer
+// (Requires: SDL 2.0.17+)
+
+// Important to understand: SDL_Renderer is an _optional_ component of SDL. We do not recommend you use SDL_Renderer
+// because it provide a rather limited API to the end-user. We provide this backend for the sake of completeness.
+// For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+// Missing features:
+//  [ ] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+
+struct SDL_Renderer;
+
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_Init(SDL_Renderer* renderer);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data);
+
+// Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_CreateFontsTexture();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_DestroyFontsTexture();
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_DestroyDeviceObjects();

backends/imgui_impl_vulkan.cpp

@@ -1088,8 +1088,9 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info, VkRenderPass rend
 
 void ImGui_ImplVulkan_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     // First destroy objects in all viewports
     ImGui_ImplVulkan_DestroyDeviceObjects();

backends/imgui_impl_win32.cpp

@@ -187,8 +187,10 @@ bool    ImGui_ImplWin32_Init(void* hwnd)
 
 void    ImGui_ImplWin32_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+
     ImGui_ImplWin32_ShutdownPlatformInterface();
 
     // Unload XInput library