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OpenSceneGraph：从源代码和Hello World构建



引言


OpenSceneGraph （以下称为OSG）是一个用C ++编写的开放式跨平台框架，它代表图形引擎，该图形引擎为程序员提供了OpenGL的对象接口。 在我们的国家，这种引擎并不是特别流行，即使在哈布雷（Habré）上，我也只看到或多或少像样的出版物 。 OSG在国外有很多使用，例如，它是免费FlightGear飞行模拟器的基础， Morrowind游戏的一种开放实现，称为OpenMW，其开发也从Ogre引擎转移到OSG。 俄语文档几乎很少，在英语文档中，只有一小部分来自开发人员的书籍可以被提及： OpenSceneGraph 3.0。 入门指南和OpenSceneGraph 3.食谱 。

尽管如此，由于以下原因，该引擎还是很有趣的：

  1. C ++中的开放式跨平台实现。
  2. 模块化架构。
  3. 通过内置插件系统可扩展。
  4. 图形数据的多线程处理的可能性以及用于其实现的内置工具
  5. 通过智能指针机制进行动态内存管理

我认为对于Habr的读者来说，更详细地了解这个项目将很有趣。 俄语OSG知识库的补充不会多余。 我将就此主题发布的所有材料均基于OpenSceneGraph 3.0。 初学者指南 ，但这不是其翻译，而是对此处介绍材料的创造性修改。 如果您对此主题感兴趣，请要求

在计算机上获取最新版本的OSG的唯一肯定方法是从源代码构建库。 Windows的现有二进制安装程序着重于MS Visual C ++编译器。 对我来说，对于我的项目，有必要使用GCC编译器，或者更确切地说，使用它的MinGW32版本，该版本包含在Qt框架开发工具中。 因此，我们需要：

  1. 使用MinGW32 5.3版编译器和QtCreator IDE安装和配置Qt框架
  2. Windows版Git客户端
  3. Windows的Cmake实用程序

期望读者熟悉Qt项目中使用的QtCreator IDE和qmake构建系统。 另外，假定读者了解使用Git版本控制系统的基础知识，并且原则上具有非零编程技能。

1.获取OpenSceneGraph源


我们在硬盘驱动器上创建一个目录，用于构建OSG，例如，沿着路径D：\ OSG



我们将转到此目录，并从Github上的官方OSG存储库获取源

D:\OSG> git clone https://github.com/openscenegraph/OpenSceneGraph.git

下载过程的时间长短取决于您的Internet访问通道的宽度。 迟早，我们将收到OSG存储库的本地副本。

下载源代码后，在附近创建build-win32-debug目录



在此目录中，我们将构建OSG调试工具包。 但是之前

2.配置cmake


为了使cmake正常工作，我们应该编辑install-path-cmake \ share \ cmake-3.13 \ Modules \ CMakeMinGWFindMake.cmake文件 。 默认情况下，它看起来像这样

 # Distributed under the OSI-approved BSD 3-Clause License. See accompanying # file Copyright.txt or https://cmake.org/licensing for details. find_program(CMAKE_MAKE_PROGRAM mingw32-make.exe PATHS "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\MinGW;InstallLocation]/bin" c:/MinGW/bin /MinGW/bin "[HKEY_CURRENT_USER\\Software\\CodeBlocks;Path]/MinGW/bin" ) find_program(CMAKE_SH sh.exe ) if(CMAKE_SH) message(FATAL_ERROR "sh.exe was found in your PATH, here:\n${CMAKE_SH}\nFor MinGW make to work correctly sh.exe must NOT be in your path.\nRun cmake from a shell that does not have sh.exe in your PATH.\nIf you want to use a UNIX shell, then use MSYS Makefiles.\n") set(CMAKE_MAKE_PROGRAM NOTFOUND) endif() mark_as_advanced(CMAKE_MAKE_PROGRAM CMAKE_SH)

我们在其中注释了几行，以使该实用程序不会尝试在我们的系统中查找Unix shell，如果找不到它，则以错误结尾

 # Distributed under the OSI-approved BSD 3-Clause License. See accompanying # file Copyright.txt or https://cmake.org/licensing for details. find_program(CMAKE_MAKE_PROGRAM mingw32-make.exe PATHS "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\MinGW;InstallLocation]/bin" c:/MinGW/bin /MinGW/bin "[HKEY_CURRENT_USER\\Software\\CodeBlocks;Path]/MinGW/bin" ) #find_program(CMAKE_SH sh.exe ) #if(CMAKE_SH) # message(FATAL_ERROR "sh.exe was found in your PATH, here:\n${CMAKE_SH}\nFor MinGW make to work correctly sh.exe must NOT be in your path.\nRun cmake from a shell that does not have sh.exe in your PATH.\nIf you want to use a UNIX shell, then use MSYS Makefiles.\n") # set(CMAKE_MAKE_PROGRAM NOTFOUND) #endif() mark_as_advanced(CMAKE_MAKE_PROGRAM CMAKE_SH)

3.组装和安装引擎的调试和发行版本


现在运行cmd shell，该快捷方式位于桌面的开始->程序-> Qt-> Qt 5.11.2-> Qt 5.11.2（MinGW 5.3.0 32bit）上



运行中的命令行会话设置了mingw32构建工具正常工作所需的整个环境。 转到OSG源目录

 C:\Qt\Qt5.11.2\5.11.2\mingw53_32>D: D:\> cd OSG\build-win32-debug

发出命令

 D:\OSG\build-win32-debug>cmake -G "MinGW Makefiles" -DCMAKE_INSTALL_PREFIX=E:\Apps\OSG -DCMAKE_BUILD_TYPE=DEBUG ../OpenSceneGraph

让我们更详细地分析参数的含义：

  • -G“ MinGW Makefiles”-表示有必要为mingw32-make实用程序生成Makefile
  • -DCMAKE_INSTALL_PREFIX = E：\ Apps \ OSG-设置OSG的安装路径
  • -DCMAKE_BUILD_TYPE = DEBUG-指示应构建引擎的调试版本。

命令的执行将检查组装环境的就绪性，生成构建脚本并进行下一步操作

配置OSG构建时Cmake耗尽
 -- The C compiler identification is GNU 5.3.0 -- The CXX compiler identification is GNU 5.3.0 -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Looking for pthread.h -- Looking for pthread.h - found -- Looking for pthread_create -- Looking for pthread_create - found -- Found Threads: TRUE -- Found OpenGL: opengl32 -- Could NOT find EGL (missing: EGL_INCLUDE_DIR) -- Checking windows version... -- Performing Test GL_HEADER_HAS_GLINT64 -- Performing Test GL_HEADER_HAS_GLINT64 - Failed -- Performing Test GL_HEADER_HAS_GLUINT64 -- Performing Test GL_HEADER_HAS_GLUINT64 - Failed -- 32 bit architecture detected -- Could NOT find Freetype (missing: FREETYPE_LIBRARY FREETYPE_INCLUDE_DIRS) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find Jasper (missing: JASPER_LIBRARIES JASPER_INCLUDE_DIR JPEG_LIBRARIES) -- Could NOT find LibXml2 (missing: LIBXML2_LIBRARY LIBXML2_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find GDAL (missing: GDAL_LIBRARY GDAL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find CURL (missing: CURL_LIBRARY CURL_INCLUDE_DIR) -- Trying to find DCMTK expecting DCMTKConfig.cmake -- Trying to find DCMTK expecting DCMTKConfig.cmake - failed -- Trying to find DCMTK relying on FindDCMTK.cmake -- Please set DCMTK_DIR and re-run configure (missing: DCMTK_config_INCLUDE_DIR DCMTK_dcmdata_INCLUDE_DIR DCMTK_dcmimage_INCLUDE_DIR DCMTK_dcmimgle_INCLUDE_DIR DCMTK_dcmjpeg_INCLUDE_DIR DCMTK_dcmjpls_INCLUDE_DIR DCMTK_dcmnet_INCLUDE_DIR DCMTK_dcmpstat_INCLUDE_DIR DCMTK_dcmqrdb_INCLUDE_DIR DCMTK_dcmsign_INCLUDE_DIR DCMTK_dcmsr_INCLUDE_DIR DCMTK_dcmtls_INCLUDE_DIR DCMTK_ofstd_INCLUDE_DIR DCMTK_oflog_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find GStreamer (missing: GSTREAMER_INCLUDE_DIRS GSTREAMER_LIBRARIES GSTREAMER_VERSION GSTREAMER_BASE_INCLUDE_DIRS GSTREAMER_BASE_LIBRARIES GSTREAMER_APP_INCLUDE_DIRS GSTREAMER_APP_LIBRARIES GSTREAMER_PBUTILS_INCLUDE_DIRS GSTREAMER_PBUTILS_LIBRARIES) (found version "") -- Could NOT find SDL2 (missing: SDL2_LIBRARY SDL2_INCLUDE_DIR) -- Could NOT find SDL (missing: SDL_LIBRARY SDL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find PNG (missing: PNG_LIBRARY PNG_PNG_INCLUDE_DIR) -- Could NOT find TIFF (missing: TIFF_LIBRARY TIFF_INCLUDE_DIR) -- g++ version 5.3.0 -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC - Failed -- Configuring done -- Generating done -- Build files have been written to: D:/OSG/build-win32-debug 配置（丢失：DCMTK_config_INCLUDE_DIR DCMTK_dcmdata_INCLUDE_DIR DCMTK_dcmimage_INCLUDE_DIR DCMTK_dcmimgle_INCLUDE_DIR DCMTK_dcmjpeg_INCLUDE_DIR DCMTK_dcmjpls_INCLUDE_DIR DCMTK_dcmnet_INCLUDE_DIR DCMTK_dcmpstat_INCLUDE_DIR DCMTK_dcmqrdb_INCLUDE_DIR DCMTK_dcmsign_INCLUDE_DIR DCMTK_dcmsr_INCLUDE_DIR DCMTK_dcmtls_INCLUDE_DIR DCMTK_ofstd_INCLUDE_DIR DCMTK_oflog_INCLUDE_DIR） -- The C compiler identification is GNU 5.3.0 -- The CXX compiler identification is GNU 5.3.0 -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Looking for pthread.h -- Looking for pthread.h - found -- Looking for pthread_create -- Looking for pthread_create - found -- Found Threads: TRUE -- Found OpenGL: opengl32 -- Could NOT find EGL (missing: EGL_INCLUDE_DIR) -- Checking windows version... -- Performing Test GL_HEADER_HAS_GLINT64 -- Performing Test GL_HEADER_HAS_GLINT64 - Failed -- Performing Test GL_HEADER_HAS_GLUINT64 -- Performing Test GL_HEADER_HAS_GLUINT64 - Failed -- 32 bit architecture detected -- Could NOT find Freetype (missing: FREETYPE_LIBRARY FREETYPE_INCLUDE_DIRS) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find Jasper (missing: JASPER_LIBRARIES JASPER_INCLUDE_DIR JPEG_LIBRARIES) -- Could NOT find LibXml2 (missing: LIBXML2_LIBRARY LIBXML2_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find GDAL (missing: GDAL_LIBRARY GDAL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find CURL (missing: CURL_LIBRARY CURL_INCLUDE_DIR) -- Trying to find DCMTK expecting DCMTKConfig.cmake -- Trying to find DCMTK expecting DCMTKConfig.cmake - failed -- Trying to find DCMTK relying on FindDCMTK.cmake -- Please set DCMTK_DIR and re-run configure (missing: DCMTK_config_INCLUDE_DIR DCMTK_dcmdata_INCLUDE_DIR DCMTK_dcmimage_INCLUDE_DIR DCMTK_dcmimgle_INCLUDE_DIR DCMTK_dcmjpeg_INCLUDE_DIR DCMTK_dcmjpls_INCLUDE_DIR DCMTK_dcmnet_INCLUDE_DIR DCMTK_dcmpstat_INCLUDE_DIR DCMTK_dcmqrdb_INCLUDE_DIR DCMTK_dcmsign_INCLUDE_DIR DCMTK_dcmsr_INCLUDE_DIR DCMTK_dcmtls_INCLUDE_DIR DCMTK_ofstd_INCLUDE_DIR DCMTK_oflog_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find GStreamer (missing: GSTREAMER_INCLUDE_DIRS GSTREAMER_LIBRARIES GSTREAMER_VERSION GSTREAMER_BASE_INCLUDE_DIRS GSTREAMER_BASE_LIBRARIES GSTREAMER_APP_INCLUDE_DIRS GSTREAMER_APP_LIBRARIES GSTREAMER_PBUTILS_INCLUDE_DIRS GSTREAMER_PBUTILS_LIBRARIES) (found version "") -- Could NOT find SDL2 (missing: SDL2_LIBRARY SDL2_INCLUDE_DIR) -- Could NOT find SDL (missing: SDL_LIBRARY SDL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find PNG (missing: PNG_LIBRARY PNG_PNG_INCLUDE_DIR) -- Could NOT find TIFF (missing: TIFF_LIBRARY TIFF_INCLUDE_DIR) -- g++ version 5.3.0 -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC - Failed -- Configuring done -- Generating done -- Build files have been written to: D:/OSG/build-win32-debug GSTREAMER_INCLUDE_DIRS GSTREAMER_LIBRARIES GSTREAMER_VERSION GSTREAMER_BASE_INCLUDE_DIRS GSTREAMER_BASE_LIBRARIES GSTREAMER_APP_INCLUDE_DIRS GSTREAMER_APP_LIBRARIES GSTREAMER_PBUTILS_INCLUDE_DIRS GSTREAMER_PBUTILS_LIBRARIES）（发现版“”） -- The C compiler identification is GNU 5.3.0 -- The CXX compiler identification is GNU 5.3.0 -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- Check for working C compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/gcc.exe -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- Check for working CXX compiler: C:/Qt/Qt5.11.2/Tools/mingw530_32/bin/g++.exe -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Looking for pthread.h -- Looking for pthread.h - found -- Looking for pthread_create -- Looking for pthread_create - found -- Found Threads: TRUE -- Found OpenGL: opengl32 -- Could NOT find EGL (missing: EGL_INCLUDE_DIR) -- Checking windows version... -- Performing Test GL_HEADER_HAS_GLINT64 -- Performing Test GL_HEADER_HAS_GLINT64 - Failed -- Performing Test GL_HEADER_HAS_GLUINT64 -- Performing Test GL_HEADER_HAS_GLUINT64 - Failed -- 32 bit architecture detected -- Could NOT find Freetype (missing: FREETYPE_LIBRARY FREETYPE_INCLUDE_DIRS) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find Jasper (missing: JASPER_LIBRARIES JASPER_INCLUDE_DIR JPEG_LIBRARIES) -- Could NOT find LibXml2 (missing: LIBXML2_LIBRARY LIBXML2_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find GDAL (missing: GDAL_LIBRARY GDAL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find CURL (missing: CURL_LIBRARY CURL_INCLUDE_DIR) -- Trying to find DCMTK expecting DCMTKConfig.cmake -- Trying to find DCMTK expecting DCMTKConfig.cmake - failed -- Trying to find DCMTK relying on FindDCMTK.cmake -- Please set DCMTK_DIR and re-run configure (missing: DCMTK_config_INCLUDE_DIR DCMTK_dcmdata_INCLUDE_DIR DCMTK_dcmimage_INCLUDE_DIR DCMTK_dcmimgle_INCLUDE_DIR DCMTK_dcmjpeg_INCLUDE_DIR DCMTK_dcmjpls_INCLUDE_DIR DCMTK_dcmnet_INCLUDE_DIR DCMTK_dcmpstat_INCLUDE_DIR DCMTK_dcmqrdb_INCLUDE_DIR DCMTK_dcmsign_INCLUDE_DIR DCMTK_dcmsr_INCLUDE_DIR DCMTK_dcmtls_INCLUDE_DIR DCMTK_ofstd_INCLUDE_DIR DCMTK_oflog_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find GStreamer (missing: GSTREAMER_INCLUDE_DIRS GSTREAMER_LIBRARIES GSTREAMER_VERSION GSTREAMER_BASE_INCLUDE_DIRS GSTREAMER_BASE_LIBRARIES GSTREAMER_APP_INCLUDE_DIRS GSTREAMER_APP_LIBRARIES GSTREAMER_PBUTILS_INCLUDE_DIRS GSTREAMER_PBUTILS_LIBRARIES) (found version "") -- Could NOT find SDL2 (missing: SDL2_LIBRARY SDL2_INCLUDE_DIR) -- Could NOT find SDL (missing: SDL_LIBRARY SDL_INCLUDE_DIR) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) -- Could NOT find ZLIB (missing: ZLIB_INCLUDE_DIR) -- Could NOT find PNG (missing: PNG_LIBRARY PNG_PNG_INCLUDE_DIR) -- Could NOT find TIFF (missing: TIFF_LIBRARY TIFF_INCLUDE_DIR) -- g++ version 5.3.0 -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_GCC_BUILTINS - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS -- Performing Test _OPENTHREADS_ATOMIC_USE_MIPOSPRO_BUILTINS - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN -- Performing Test _OPENTHREADS_ATOMIC_USE_SUN - Failed -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED -- Performing Test _OPENTHREADS_ATOMIC_USE_WIN32_INTERLOCKED - Success -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC -- Performing Test _OPENTHREADS_ATOMIC_USE_BSD_ATOMIC - Failed -- Configuring done -- Generating done -- Build files have been written to: D:/OSG/build-win32-debug



告诉我们您可以开始组装。 发出命令

 D:\OSG\build-win32-debug>mingw32-make -j9

如我的示例所示，如果您有多核处理器（-j开关），则可以指定汇编线程的数量。 构建过程将开始，在我的计算机上大约需要八分钟



在组装结束时，安装库

 D:\OSG\build-win32-debug> mingw32-make install

执行命令后，我们找到安装在我们先前设置的路径中的库



现在，通过创建另一个构建目录来构建引擎的发行版

 D:\OSG\build-win32-debug>cd .. D:\OSG> mkdir build-win32-release D:\OSG>cd build-win32-release D:\OSG\build-win32-release> cmake -G "MinGW Makefiles" -DCMAKE_INSTALL_PREFIX=E:\Apps\OSG ../OpenSceneGraph D:\OSG\build-win32-release> mingw32-make -j9 D:\OSG\build-win32-release> mingw32-make install

4.设置环境变量


安装后OSG库的位置可以是任何位置-由特定用户的意愿及其在计算机上放置文件的能力来确定。 同时，在建立使用数据的特定项目时，库需要某种统一，从库的特定位置进行抽象。

让我们创建一些系统环境变量，这些变量指示库，头文件和OSG插件的路径。 在我的示例中，它看起来像这样



必须创建其名称在屏幕快照中用红色圈出的变量。 创建变量后，为了使它们能够被开发工具看到，尤其是QtCreator需要至少登录系统（注销并以当前用户身份登录），或者可能地，重新引导系统（这是Windows！）。

之后，可以认为在我们的计算机上安装OSG的过程已完成。

5.将Hello World写入QtCreator


我们将以一个简单的示例开始熟悉OpenSceneGraph图形引擎，这是在使用某些“ Hello world！”进行编程时惯常使用的示例。

在编写任何代码之前，我们将为qmake构建系统配置项目，我们将在整个系列文章中使用该系统。 在我们感兴趣的文件系统中，创建以下目录结构

 OSG-lessons/ |-data/ |-OSG-lessons/ | |-hello/ |-include/ |-src/

在hello目录中，创建具有以下内容的hello.pro文件

全文hello.pro
 TEMPLATE = app TARGET = hello DESTDIR = ../../bin win32 { OSG_LIB_DIRECTORY = $$(OSG_BIN_PATH) OSG_INCLUDE_DIRECTORY = $$(OSG_INCLUDE_PATH) CONFIG(debug, debug|release) { TARGET = $$join(TARGET,,,_d) LIBS += -L$$OSG_LIB_DIRECTORY -losgd LIBS += -L$$OSG_LIB_DIRECTORY -losgViewerd LIBS += -L$$OSG_LIB_DIRECTORY -losgDBd LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreadsd } else { LIBS += -L$$OSG_LIB_DIRECTORY -losg LIBS += -L$$OSG_LIB_DIRECTORY -losgViewer LIBS += -L$$OSG_LIB_DIRECTORY -losgDB LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreads } INCLUDEPATH += $$OSG_INCLUDE_DIRECTORY } unix { CONFIG(debug, debug|release) { TARGET = $$join(TARGET,,,_d) LIBS += -losgd LIBS += -losgViewerd LIBS += -losgDBd LIBS += -lOpenThreadsd } else { LIBS += -losg LIBS += -losgViewer LIBS += -losgDB LIBS += -lOpenThreads } } INCLUDEPATH += ./include HEADERS += $$files(./include/*.h) SOURCES += $$files(./src/*.cpp)

我们将更详细地分析这些字母。

 TEMPLATE = app TARGET = hello DESTDIR = ../../bin


变量指定项目模板（应用程序-应用程序），可执行文件的名称（hello）以及汇编后可执行文件的放置目录。

 win32 { OSG_LIB_DIRECTORY = $$(OSG_BIN_PATH) OSG_INCLUDE_DIRECTORY = $$(OSG_INCLUDE_PATH) CONFIG(debug, debug|release) { TARGET = $$join(TARGET,,,_d) LIBS += -L$$OSG_LIB_DIRECTORY -losgd LIBS += -L$$OSG_LIB_DIRECTORY -losgViewerd LIBS += -L$$OSG_LIB_DIRECTORY -losgDBd LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreadsd } else { LIBS += -L$$OSG_LIB_DIRECTORY -losg LIBS += -L$$OSG_LIB_DIRECTORY -losgViewer LIBS += -L$$OSG_LIB_DIRECTORY -losgDB LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreads } INCLUDEPATH += $$OSG_INCLUDE_DIRECTORY }

根据组装项目的OS，我们定义变量，这些变量指示库目录和OSG头文件的路径。 这是OSG_BIN_PATH和OSG_INCLUDE_PATH环境变量派上用场的地方-现在，在哪里安装OSG库都无关紧要。 任何想要在其计算机上使用此项目的人都将在其系统中编写适当的环境变量，而无需编辑构建脚本。

 CONFIG(debug, debug|release) { TARGET = $$join(TARGET,,,_d) LIBS += -L$$OSG_LIB_DIRECTORY -losgd LIBS += -L$$OSG_LIB_DIRECTORY -losgViewerd LIBS += -L$$OSG_LIB_DIRECTORY -losgDBd LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreadsd } else { LIBS += -L$$OSG_LIB_DIRECTORY -losg LIBS += -L$$OSG_LIB_DIRECTORY -losgViewer LIBS += -L$$OSG_LIB_DIRECTORY -losgDB LIBS += -L$$OSG_LIB_DIRECTORY -lOpenThreads }

编写脚本以在类似Unix的操作系统中进行构建

 unix { CONFIG(debug, debug|release) { TARGET = $$join(TARGET,,,_d) LIBS += -losgd LIBS += -losgViewerd LIBS += -losgDBd LIBS += -lOpenThreadsd } else { LIBS += -losg LIBS += -losgViewer LIBS += -losgDB LIBS += -lOpenThreads } }

在这里，我们配置可执行文件的名称，并为各种构建选项（调试和发布）指定应由我们的程序编译的库。 OSG调试库在文件名后带有后缀“ d”。 我们将后缀“ _d”添加到项目的可执行文件中，以便将调试选项与发行版区分开。

 INCLUDEPATH += $$OSG_INCLUDE_DIRECTORY INCLUDEPATH += ./include HEADERS += $$files(./include/*.h) SOURCES += $$files(./src/*.cpp)

最后，我们确定头文件和项目树中包含的文件的搜索路径。 在include /目录中创建一个空的main.h文件，在src /目录中创建一个main.cpp文件。 我们在QtCreator中打开该项目并按屏幕快照所示进行配置



打开项目后，我们将看到以下图片



我们将这样的代码写入main.h文件中

 #ifndef MAIN_H #define MAIN_H #include <osgDB/ReadFile> #include <osgViewer/Viewer> #endif

接下来，我们在main.cpp文件中实现程序的主体

 #include "main.h" int main(int argc, char *argv[]) { (void) argc; (void) argv; osg::ref_ptr<osg::Node> root = osgDB::readNodeFile("../data/cessna.osg"); osgViewer::Viewer viewer; viewer.setSceneData(root.get()); return viewer.run(); }

飞机模型文件必须复制到数据/目录。 可以从OpenSceneGraph-Data存储库下载该文件以及本系列文章中将使用的大部分文件。

编译并运行后，我们得到如下内容



代码的前两行

 (void) argc; (void) argv;

将main（）函数的输入参数标记为未使用，以避免编译器警告。 接下来，创建场景的根节点，这是从cessna.osg文件加载的飞机的模型

 osg::ref_ptr<osg::Node> root = osgDB::readNodeFile("../data/cessna.osg");

然后，创建osgViewer :: Viewer类的实例-所谓的“ viewer”-一个对象，该对象控制屏幕上场景的显示。 场景数据传递给查看器

 viewer.setSceneData(root.get());

场景渲染周期开始

 return viewer.run();

这个最简单的代码已经包含OSG中使用的许多基本概念。 但是谈论它们会稍晚一些。

结论


此处描述的示例的完整源代码可在此处获得 。 我希望该出版物引起读者的兴趣， 并继续...

Source: https://habr.com/ru/post/zh-CN429816/

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