Null backend always available

pthom · May 6, 2024 · da24e13 · da24e13
1 parent 25f89c6
commit da24e13
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Showing 9 changed files with 42 additions and 53 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -82,17 +82,18 @@ 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)
+# Headless mode: by default, HelloImGui's cmake tooling will always check that there is at least one
+# rendering backend and one platform backend that is not a "Null" backend.
+# If you set HELLOIMGUI_HEADLESS, you can disable this check, and compile HelloImGui,
+# using only the Null rendering/platform backends.
+option(HELLOIMGUI_HEADLESS "Allow headless mode (will use Null rendering/platform backend)" OFF)
 # </Backends>  # do not remove this line (used by the script that generates the documentation)
 
 #------------------------------------------------------------------------------

diff --git a/CMakePresets.json b/CMakePresets.json
@@ -3,38 +3,36 @@
   "configurePresets": [
     {
       "name": "build_default_glfw",
-      "description": "Build with default settings (opengl3 and glfw). You need to create a build directory and run from it",
+      "description": "Build with default settings (opengl3 and glfw)",
       "cacheVariables": {
         "HELLOIMGUI_USE_GLFW3": "ON",
         "HELLOIMGUI_HAS_OPENGL3": "ON"
       }
     },
     {
       "name": "build_default_sdl",
-      "description": "Build with default settings (opengl3 and sdl). You need to create a build directory and run from it",
+      "description": "Build with default settings (opengl3 and sdl)",
       "cacheVariables": {
         "HELLOIMGUI_USE_SDL2": "ON",
         "HELLOIMGUI_HAS_OPENGL3": "ON"
       }
     },
     {
       "name": "build_all_backends",
-      "description": "Build with all platform and renderer backends. You need to create a build directory and run from it",
+      "description": "Build with all platform and renderer backends",
       "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_NULL": "ON"
+        "HELLOIMGUI_HAS_DIRECTX12": "ON"
       }
     },
     {
       "name": "build_vcpkg_default",
-      "description": "Build with vcpkg default settings (opengl3 + sdl and glfw). You need to create a build directory and run from it",
+      "description": "Build with vcpkg default settings (opengl3 + sdl and glfw)",
       "cacheVariables": {
         "CMAKE_TOOLCHAIN_FILE": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
         "HELLOIMGUI_USE_GLFW3": "ON",
@@ -45,8 +43,7 @@
     },
     {
       "name": "build_use_vcpkg_opengl3",
-      "description": "Build with vcpkg default settings (opengl3 + sdl and glfw). Will build inside build_use_vcpkg_opengl3/",
-      "binaryDir": "${sourceDir}/build_use_vcpkg_opengl3",
+      "description": "Build with vcpkg default settings (opengl3 + sdl and glfw)",
       "cacheVariables": {
         "CMAKE_TOOLCHAIN_FILE": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
         "HELLOIMGUI_USE_GLFW3": "ON",
@@ -57,8 +54,7 @@
     },
     {
       "name": "build_use_vcpkg_metal",
-      "description": "Build with vcpkg (for metal + sdl and glfw). Will build inside build_use_vcpkg_metal/",
-      "binaryDir": "${sourceDir}/build_use_vcpkg_metal",
+      "description": "Build with vcpkg (for metal + sdl and glfw)",
       "cacheVariables": {
         "CMAKE_TOOLCHAIN_FILE": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
         "HELLOIMGUI_USE_GLFW3": "ON",
@@ -69,15 +65,21 @@
     },
     {
       "name": "build_use_vcpkg_vulkan",
-      "description": "Build with vcpkg (for vulkan + sdl and glfw). Will build inside build_use_vcpkg_vulkan/",
-      "binaryDir": "${sourceDir}/build_use_vcpkg_vulkan",
+      "description": "Build with vcpkg (for vulkan + sdl and glfw)",
       "cacheVariables": {
         "CMAKE_TOOLCHAIN_FILE": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
         "HELLOIMGUI_USE_GLFW3": "ON",
         "HELLOIMGUI_USE_SDL2": "ON",
         "HELLOIMGUI_HAS_VULKAN": "ON",
         "HELLOIMGUI_USE_IMGUI_CMAKE_PACKAGE": "ON"
       }
+    },
+    {
+      "name": "build_headless",
+      "description": "Build with headless backend. No GUI will be shown",
+      "cacheVariables": {
+        "HELLOIMGUI_HEADLESS": "ON"
+      }
     }
   ]
 }
diff --git a/hello_imgui_cmake/hello_imgui_build_lib.cmake b/hello_imgui_cmake/hello_imgui_build_lib.cmake
@@ -34,7 +34,6 @@ function(him_back_available_platform_backends out_var)
     set(${out_var}
         HELLOIMGUI_USE_SDL2
         HELLOIMGUI_USE_GLFW3
-        HELLOIMGUI_USE_NULL
         PARENT_SCOPE)
 endfunction()
 
@@ -45,15 +44,10 @@ 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,
@@ -163,6 +157,10 @@ function(him_back_check_if_no_rendering_backend_selected out_var) # will set out
 endfunction()
 
 function(him_back_check_if_no_backend_option_chosen out_var)
+    if (HELLOIMGUI_HEADLESS)
+        set(${out_var} OFF PARENT_SCOPE)
+        return()
+    endif()
     him_back_check_if_no_platform_backend_selected(no_platform_selected)
     him_back_check_if_no_rendering_backend_selected(no_rendering_selected)
     if(no_platform_selected AND no_rendering_selected)
@@ -173,6 +171,10 @@ function(him_back_check_if_no_backend_option_chosen out_var)
 endfunction()
 
 function(him_back_check_at_least_one_rendering_one_platform_backend out_var)
+    if (HELLOIMGUI_HEADLESS)
+        set(${out_var} ON PARENT_SCOPE)
+        return()
+    endif()
     him_back_check_if_no_platform_backend_selected(no_platform_selected)
     him_back_check_if_no_rendering_backend_selected(no_rendering_selected)
     if(no_platform_selected OR no_rendering_selected)
@@ -190,6 +192,11 @@ function(him_back_describe_active_rendering_backends out_description)
             set(result "${result} ${backend}")
         endif()
     endforeach()
+
+    if (HELLOIMGUI_HEADLESS)
+        set(result "${result} null-headless")
+    endif()
+
     set(${out_description} ${result} PARENT_SCOPE)
 endfunction()
 
@@ -201,6 +208,11 @@ function(him_back_describe_active_platform_backends out_description)
             set(result "${result} ${backend}")
         endif()
     endforeach()
+
+    if (HELLOIMGUI_HEADLESS)
+        set(result "${result} null-headless")
+    endif()
+
     set(${out_description} ${result} PARENT_SCOPE)
 endfunction()
 
@@ -1212,9 +1224,6 @@ 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(${HELLOIMGUI_TARGET})
@@ -1231,9 +1240,6 @@ function(him_main_add_hello_imgui_library)
     if (HELLOIMGUI_HAS_DIRECTX12)
         him_has_directx12(${HELLOIMGUI_TARGET})
     endif()
-    if (HELLOIMGUI_HAS_NULL)
-        target_compile_definitions(${HELLOIMGUI_TARGET} PUBLIC HELLOIMGUI_HAS_NULL)
-    endif()
 
     if (HELLOIMGUI_WITH_NETIMGUI)
         him_with_netimgui()

diff --git a/src/hello_imgui/internal/backend_impls/abstract_runner.cpp b/src/hello_imgui/internal/backend_impls/abstract_runner.cpp
@@ -649,11 +649,7 @@ void AbstractRunner::InitRenderBackendCallbacks()
     }
     else if (params.rendererBackendType == RendererBackendType::Null)
     {
-        #ifdef HELLOIMGUI_USE_NULL
-            mRenderingBackendCallbacks = CreateBackendCallbacks_Null();
-        #else
-            IM_ASSERT(false && "Null backend is not available!");
-        #endif
+        mRenderingBackendCallbacks = CreateBackendCallbacks_Null();
     }
     else
     {

diff --git a/src/hello_imgui/internal/backend_impls/backend_window_helper/null_window_helper.h b/src/hello_imgui/internal/backend_impls/backend_window_helper/null_window_helper.h
@@ -1,5 +1,4 @@
 #pragma once
-#ifdef HELLOIMGUI_USE_NULL
 
 #include "backend_window_helper.h"
 #include "hello_imgui/internal/backend_impls/null_config.h"
@@ -51,5 +50,3 @@ namespace HelloImGui { namespace BackendApi
 
     };
 }} // namespace HelloImGui { namespace BackendApi
-
-#endif // #ifdef HELLOIMGUI_USE_NULL
diff --git a/src/hello_imgui/internal/backend_impls/rendering_null.cpp b/src/hello_imgui/internal/backend_impls/rendering_null.cpp
@@ -1,4 +1,3 @@
-#ifdef HELLOIMGUI_HAS_NULL
 #include "rendering_null.h"
 
 
@@ -25,5 +24,3 @@ namespace HelloImGui
     }
 
 }
-
-#endif
diff --git a/src/hello_imgui/internal/backend_impls/rendering_null.h b/src/hello_imgui/internal/backend_impls/rendering_null.h
@@ -1,11 +1,8 @@
 #pragma once
-#ifdef HELLOIMGUI_HAS_NULL
 
 #include "hello_imgui/internal/backend_impls/rendering_callbacks.h"
 
 namespace HelloImGui
 {
     RenderingCallbacksPtr CreateBackendCallbacks_Null();
 }
-
-#endif
diff --git a/src/hello_imgui/internal/backend_impls/runner_factory.cpp b/src/hello_imgui/internal/backend_impls/runner_factory.cpp
@@ -16,7 +16,7 @@ void ChooseBackendTypesIfSelectedAsFirstAvailable(RunnerParams* runnerParams)
             runnerParams->platformBackendType = PlatformBackendType::Glfw;
         #elif defined(HELLOIMGUI_USE_SDL2)
             runnerParams->platformBackendType = PlatformBackendType::Sdl;
-        #elif defined(HELLOIMGUI_USE_NULL)
+        #else
             runnerParams->platformBackendType = PlatformBackendType::Null;
         #endif
     }
@@ -33,7 +33,7 @@ void ChooseBackendTypesIfSelectedAsFirstAvailable(RunnerParams* runnerParams)
             runnerParams->rendererBackendType = RendererBackendType::DirectX11;
         #elif defined(HELLOIMGUI_HAS_DIRECTX12)
             runnerParams->rendererBackendType = RendererBackendType::DirectX12;
-        #elif defined(HELLOIMGUI_HAS_NULL)
+        #else
             runnerParams->rendererBackendType = RendererBackendType::Null;
         #endif
     }
@@ -75,11 +75,7 @@ std::unique_ptr<AbstractRunner> FactorRunner(RunnerParams& params)
     }
     else if (params.platformBackendType == PlatformBackendType::Null)
     {
-        #ifdef HELLOIMGUI_USE_NULL
-            return std::make_unique<RunnerNull>(params);
-        #else
-            return nullptr;
-        #endif
+        return std::make_unique<RunnerNull>(params);
     }
     else
         return nullptr;

diff --git a/src/hello_imgui/internal/backend_impls/runner_null.h b/src/hello_imgui/internal/backend_impls/runner_null.h
@@ -1,5 +1,4 @@
 #pragma once
-#ifdef HELLOIMGUI_USE_NULL
 #include "hello_imgui/internal/backend_impls/abstract_runner.h"
 #include "hello_imgui/internal/backend_impls/backend_window_helper/null_window_helper.h"
 #include "hello_imgui/internal/backend_impls/null_config.h"
@@ -43,5 +42,3 @@ namespace HelloImGui
     };
 
 }  // namespace HelloImGui
-
-#endif  // #ifdef HELLOIMGUI_USE_NULL