Merge branch 'master' of https://github.com/pthom/hello_imgui

CMakeLists.txt

@@ -82,12 +82,17 @@ option(HELLOIMGUI_ADD_APP_WITH_INSTALL "Add cmake install() instructions with he
 # Platform backends:
 option(HELLOIMGUI_USE_GLFW3 "Use Glfw3 as a platform backend" OFF)
 option(HELLOIMGUI_USE_SDL2 "Use Sdl2 as a platform backend" OFF)
+option(HELLOIMGUI_USE_NULL "Null platform backend" OFF)  # for testing and remote rendering
 # Rendering backends
 option(HELLOIMGUI_HAS_OPENGL3 "Use OpenGL3 as a rendering backend" OFF)
 option(HELLOIMGUI_HAS_METAL "Use Metal as a rendering backend" OFF)
 option(HELLOIMGUI_HAS_VULKAN "Use Vulkan as a rendering backend" OFF)
 option(HELLOIMGUI_HAS_DIRECTX11 "Use DirectX11 as a rendering backend" OFF)
 option(HELLOIMGUI_HAS_DIRECTX12 "Use DirectX12 as a rendering backend" OFF)
+option(HELLOIMGUI_HAS_NULL "Null rendering backend" OFF)  # for testing and remote rendering
+
+# Null backend: useful for testing, or for remote rendering (will set both rendering and platform backends to null)
+option(HELLOIMGUI_NULL_BACKEND "Use Null rendering/platform backend" OFF)
 # </Backends>  # do not remove this line (used by the script that generates the documentation)
 
 

CMakePresets.json

@@ -23,11 +23,20 @@
       "cacheVariables": {
         "HELLOIMGUI_USE_SDL2": "ON",
         "HELLOIMGUI_USE_GLFW3": "ON",
+        "HELLOIMGUI_USE_NULL": "ON",
         "HELLOIMGUI_HAS_OPENGL3": "ON",
         "HELLOIMGUI_HAS_METAL": "ON",
         "HELLOIMGUI_HAS_VULKAN": "ON",
         "HELLOIMGUI_HAS_DIRECTX11": "ON",
-        "HELLOIMGUI_HAS_DIRECTX12": "ON"
+        "HELLOIMGUI_HAS_DIRECTX12": "ON",
+        "HELLOIMGUI_HAS_NULL": "ON"
+      }
+    },
+    {
+      "name": "build_null_backend",
+      "description": "Build with null backend.",
+      "cacheVariables": {
+        "HELLOIMGUI_NULL_BACKEND": "ON"
       }
     },
     {

hello_imgui_cmake/hello_imgui_build_lib.cmake

@@ -34,6 +34,7 @@ function(him_back_available_platform_backends out_var)
     set(${out_var}
         HELLOIMGUI_USE_SDL2
         HELLOIMGUI_USE_GLFW3
+        HELLOIMGUI_USE_NULL
         PARENT_SCOPE)
 endfunction()
 
@@ -44,10 +45,15 @@ function(him_back_available_rendering_backends out_var)
         HELLOIMGUI_HAS_VULKAN
         HELLOIMGUI_HAS_DIRECTX11
         HELLOIMGUI_HAS_DIRECTX12
+        HELLOIMGUI_HAS_NULL
         PARENT_SCOPE)
 endfunction()
 
 function(him_back_parse_legacy_combinations)
+    if(HELLOIMGUI_NULL_BACKEND)
+        set(HELLOIMGUI_USE_NULL ON CACHE BOOL "" FORCE)
+        set(HELLOIMGUI_HAS_NULL ON CACHE BOOL "" FORCE)
+    endif()
     if(HELLOIMGUI_USE_SDL_OPENGL3)
         message(WARNING "
         HELLOIMGUI_USE_SDL_OPENGL3 is deprecated,
@@ -1156,6 +1162,9 @@ function(him_main_add_hello_imgui_library)
     if (HELLOIMGUI_USE_GLFW3)
         him_use_glfw3_backend(${HELLOIMGUI_TARGET})
     endif()
+    if (HELLOIMGUI_USE_NULL)
+        target_compile_definitions(${HELLOIMGUI_TARGET} PUBLIC HELLOIMGUI_USE_NULL)
+    endif()
 
     if (HELLOIMGUI_HAS_OPENGL3)
         him_has_opengl3(${HELLOIMGUI_TARGET})
@@ -1172,6 +1181,9 @@ function(him_main_add_hello_imgui_library)
     if (HELLOIMGUI_HAS_DIRECTX12)
         him_has_directx12(${HELLOIMGUI_TARGET})
     endif()
+    if (HELLOIMGUI_HAS_NULL)
+        target_compile_definitions(${HELLOIMGUI_TARGET} PUBLIC HELLOIMGUI_HAS_NULL)
+    endif()
 
     him_add_apple_options()
     him_add_linux_options()

src/hello_imgui/impl/hello_imgui.cpp

@@ -152,27 +152,42 @@ namespace ChronoShenanigans
 
 }
 
-float FrameRate(float durationForMean)
+static std::deque<float> gFrameTimes;
+
+void _UpdateFrameRateStats()
 {
-    static std::deque<float> times;
     float now = ChronoShenanigans::ClockSeconds();
-    times.push_back(now);
-    if (times.size() <= 1)
+    gFrameTimes.push_back(now);
+
+    size_t maxFrameCount = 300;
+    while (gFrameTimes.size() > maxFrameCount)
+        gFrameTimes.pop_front();
+};
+
+float FrameRate(float durationForMean)
+{
+    if (gFrameTimes.size() <= 1)
         return 0.f;
 
-    while (true)
+    float lastFrameTime = gFrameTimes.back();
+    int lastFrameIdx = (int)gFrameTimes.size() - 1;
+
+    // Go back in frame times to find the first frame that is not too old
+    int i = (int)gFrameTimes.size() - 1;
+    while (i > 0)
     {
-        float firstTime = times.front();
-        float age = now - firstTime;
-        if ((age > durationForMean) && (times.size() >= 3))
-            times.pop_front();
-        else
+        if (lastFrameTime - gFrameTimes[i] > durationForMean)
             break;
+        --i;
     }
+    if (i == lastFrameIdx)
+        return 0.f;
+    // printf("i=%d, lastFrameIdx=%d\n", i, lastFrameIdx);
 
-    float totalTime = times.back() - times.front();
-    int nbFrames = (int)times.size();
-    float fps = 1.f / (totalTime / (float) (nbFrames - 1));
+    // Compute the mean frame rate
+    float totalTime = lastFrameTime - gFrameTimes[i];
+    int nbFrames = lastFrameIdx - i;
+    float fps =  (float)nbFrames / totalTime;
     return fps;
 }
 

src/hello_imgui/internal/backend_impls/abstract_runner.cpp

@@ -52,6 +52,7 @@
 #include "rendering_vulkan.h"
 #include "rendering_dx11.h"
 #include "rendering_dx12.h"
+#include "rendering_null.h"
 
 //
 // NOTE: AbstractRunner should *not* care in any case of:
@@ -578,6 +579,14 @@ void AbstractRunner::InitRenderBackendCallbacks()
             IM_ASSERT(false && "DirectX12 backend is not available!");
         #endif
     }
+    else if (params.rendererBackendType == RendererBackendType::Null)
+    {
+        #ifdef HELLOIMGUI_USE_NULL
+            mRenderingBackendCallbacks = CreateBackendCallbacks_Null();
+        #else
+            IM_ASSERT(false && "Null backend is not available!");
+        #endif
+    }
     else
     {
         fprintf(stderr, "Missing rendering backend! %s\n", gMissingBackendErrorMessage.c_str());
@@ -737,6 +746,8 @@ void AbstractRunner::RenderGui()
 }
 
 
+void _UpdateFrameRateStats(); // See hello_imgui.cpp
+
 void AbstractRunner::CreateFramesAndRender()
 {
     // Notes:
@@ -760,11 +771,17 @@ void AbstractRunner::CreateFramesAndRender()
     //    any user callback (which may call python functions)
     // -
 
-    // `true_gil` is a synonym for "true" (whenever using Python or not using Python)
-    // (it is here only to make the code more readable)
-    constexpr bool true_gil = true;
+    // `foldable_region` is a synonym for "true" (whenever using Python or not using Python)
+    // (it is here only to make the code more readable, and to enable to collapse blocks of code)
+    constexpr bool foldable_region = true;
+
+    if (foldable_region) // Update frame rate stats
+    {
+        _UpdateFrameRateStats();
+        // printf("Render frame %i, fps=%.1f\n", mIdxFrame, HelloImGui::FrameRate());
+    }
 
-    if (true_gil) // basic layout checks
+    if (foldable_region) // basic layout checks
     { // SCOPED_RELEASE_GIL_ON_MAIN_THREAD start
         SCOPED_RELEASE_GIL_ON_MAIN_THREAD;
 
@@ -780,7 +797,7 @@ void AbstractRunner::CreateFramesAndRender()
         #endif
     } // SCOPED_RELEASE_GIL_ON_MAIN_THREAD end
 
-    if (true) // Register tests
+    if (foldable_region) // Register tests
     {
         #ifdef HELLOIMGUI_WITH_TEST_ENGINE
         // This block calls a user callback, so it cannot be inside SCOPED_RELEASE_GIL_ON_MAIN_THREAD
@@ -795,7 +812,7 @@ void AbstractRunner::CreateFramesAndRender()
         #endif
     }
 
-    if (true_gil) // handle window size and position on first frames
+    if (foldable_region) // handle window size and position on first frames
     { // SCOPED_RELEASE_GIL_ON_MAIN_THREAD start
         SCOPED_RELEASE_GIL_ON_MAIN_THREAD;
 
@@ -860,7 +877,7 @@ void AbstractRunner::CreateFramesAndRender()
         }
     }  // SCOPED_RELEASE_GIL_ON_MAIN_THREAD end
 
-    if(true_gil) // Handle idling
+    if(foldable_region) // Handle idling
     { // SCOPED_RELEASE_GIL_ON_MAIN_THREAD start
         SCOPED_RELEASE_GIL_ON_MAIN_THREAD;
 
@@ -884,7 +901,7 @@ void AbstractRunner::CreateFramesAndRender()
         #endif
     } // SCOPED_RELEASE_GIL_ON_MAIN_THREAD end
 
-    if (true_gil) // Load additional fonts during execution
+    if (foldable_region) // Load additional fonts during execution
     {
         if (params.callbacks.LoadAdditionalFonts != nullptr)
         {
@@ -904,7 +921,7 @@ void AbstractRunner::CreateFramesAndRender()
     if (params.callbacks.PreNewFrame)
         params.callbacks.PreNewFrame();
 
-    if (true_gil)  // New Frame / Rendering and Platform Backend (not ImGui)
+    if (foldable_region)  // New Frame / Rendering and Platform Backend (not ImGui)
     { // SCOPED_RELEASE_GIL_ON_MAIN_THREAD start
         SCOPED_RELEASE_GIL_ON_MAIN_THREAD;
 
@@ -958,7 +975,7 @@ void AbstractRunner::CreateFramesAndRender()
     if (params.callbacks.BeforeImGuiRender)
         params.callbacks.BeforeImGuiRender();
 
-    if (true_gil) // Render and Swap
+    if (foldable_region) // Render and Swap
     { // SCOPED_RELEASE_GIL_ON_MAIN_THREAD start
         SCOPED_RELEASE_GIL_ON_MAIN_THREAD;
 

src/hello_imgui/internal/backend_impls/backend_window_helper/null_window_helper.h

@@ -0,0 +1,48 @@
+#pragma once
+#ifdef HELLOIMGUI_USE_NULL
+
+#include "backend_window_helper.h"
+#include "hello_imgui/internal/backend_impls/null_config.h"
+#include <thread>
+
+#ifdef _WIN32
+#ifdef CreateWindow
+#undef CreateWindow
+#endif
+#endif
+
+
+namespace HelloImGui { namespace BackendApi
+{
+    class NullWindowHelper: public IBackendWindowHelper
+    {
+        // Note: this is a fake class, it has no member
+        // It is only a class in order to enforce a consistent API between backends.
+    public:
+        WindowPointer CreateWindow(AppWindowParams &appWindowParams, const BackendOptions& backendOptions) override {
+            return nullptr;
+        }
+
+        std::vector<ScreenBounds> GetMonitorsWorkAreas() override { return NullConfig::GetMonitorsWorkAreas();}
+
+        bool IsWindowIconified(WindowPointer window) override { return false; }
+        void RaiseWindow(WindowPointer window) override {}
+
+        ScreenBounds GetWindowBounds(WindowPointer window) override { return {}; }
+        void SetWindowBounds(WindowPointer window, ScreenBounds windowBounds) override {}
+
+        void WaitForEventTimeout(double timeout_seconds) override {
+            std::this_thread::sleep_for(std::chrono::milliseconds((int)(timeout_seconds * 1000)));
+        }
+
+        ImVec2 GetWindowScaleFactor(WindowPointer window) override { return NullConfig::GetWindowScaleFactor(); }
+        float GetWindowSizeDpiScaleFactor(WindowPointer window) override { return NullConfig::GetWindowSizeDpiScaleFactor(); }
+
+        void HideWindow(WindowPointer window) override {}
+        void ShowWindow(WindowPointer window) override {}
+        bool IsWindowHidden(WindowPointer window) override { return false; }
+
+    };
+}} // namespace HelloImGui { namespace BackendApi
+
+#endif // #ifdef HELLOIMGUI_USE_NULL

src/hello_imgui/internal/backend_impls/null_config.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "hello_imgui/screen_bounds.h"
+#include "imgui.h"
+#include <vector>
+
+namespace HelloImGui
+{
+namespace NullConfig
+{
+    ScreenBounds GetScreenBounds()
+    {
+        ScreenBounds bounds;
+        bounds.size = {1920, 1080};
+        bounds.position = {0, 0};
+        return {bounds};
+    }
+
+    std::vector<ScreenBounds> GetMonitorsWorkAreas()
+    {
+        return {GetScreenBounds()};
+    }
+
+    ImVec2 GetWindowScaleFactor() { return {1.f, 1.f}; }
+    float GetWindowSizeDpiScaleFactor() { return 1.f; }
+
+}
+
+}

src/hello_imgui/internal/backend_impls/rendering_null.cpp

@@ -0,0 +1,29 @@
+#ifdef HELLOIMGUI_HAS_NULL
+#include "rendering_null.h"
+
+
+namespace HelloImGui
+{
+    RenderingCallbacksPtr CreateBackendCallbacks_Null()
+    {
+        auto callbacks = std::make_shared<RenderingCallbacks>();
+
+        callbacks->Impl_NewFrame_3D = [] {};
+
+        callbacks->Impl_RenderDrawData_To_3D = [] {};
+
+        callbacks->Impl_ScreenshotRgb_3D = []() { return ImageBuffer{}; };
+
+        callbacks->Impl_Frame_3D_ClearColor = [](ImVec4) {};
+
+        callbacks->Impl_Shutdown_3D = [] {};
+
+        callbacks->Impl_CreateFontTexture = [] {};
+        callbacks->Impl_DestroyFontTexture = [] {};
+
+        return callbacks;
+    }
+
+}
+
+#endif

src/hello_imgui/internal/backend_impls/rendering_null.h

@@ -0,0 +1,11 @@
+#pragma once
+#ifdef HELLOIMGUI_HAS_NULL
+
+#include "hello_imgui/internal/backend_impls/rendering_callbacks.h"
+
+namespace HelloImGui
+{
+    RenderingCallbacksPtr CreateBackendCallbacks_Null();
+}
+
+#endif