最近需要支持多格式的3D模型文件, 例如 glTF, GLB, 3mf , 发现 OSG 并不支持这些格式文件的解析, 网上就找到了一个 Assimp 的库. 功能还是蛮强大的,支持的格式也是很多. 所以就编译了下, Android, IOS 都能正常编译成功.

Assimp 的具体介绍就不说了, 感兴趣的可以到Assimp github 地址查看.
下面直接贴上编译脚本.

Android 编译脚本

下载源码后, 在源码内新建 androidBuilder.sh 文件, (我是 Mac 系统)

#!/bin/bash

# 设置默认值
ANDROID_PLATFORM=24
read -p "Enter Android platform (default is ${ANDROID_PLATFORM}): " input_platform
ANDROID_PLATFORM=${input_platform:-$ANDROID_PLATFORM}

ANDROID_ABI="armeabi-v7a"
read -p "Enter Android ABI (armeabi-v7a, arm64-v8a, x86, x86_64) - default is ${ANDROID_ABI}: " input_abi
ANDROID_ABI=${input_abi:-$ANDROID_ABI}

COMMON_CXX_FLAGS="-DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fexceptions -frtti -stdlib=libc++ -O3 -DNDEBUG"
COMMON_C_FLAGS="-DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fexceptions -O3 -DNDEBUG"

if [ "$ANDROID_ABI" == "armeabi-v7a" ]; then
  CXX_FLAGS="$COMMON_CXX_FLAGS -march=armv7-a -mthumb --target=armv7-none-linux-androideabi${ANDROID_PLATFORM}"
  C_FLAGS="$COMMON_C_FLAGS -march=armv7-a -mthumb --target=armv7-none-linux-androideabi${ANDROID_PLATFORM}"
elif [ "$ANDROID_ABI" == "arm64-v8a" ]; then
  CXX_FLAGS="$COMMON_CXX_FLAGS -march=armv8-a --target=aarch64-none-linux-android${ANDROID_PLATFORM}"
  C_FLAGS="$COMMON_C_FLAGS -march=armv8-a --target=aarch64-none-linux-android${ANDROID_PLATFORM}"
fi

# ANDROID_NDK_PATH="/Users/yaqi/Library/Android/sdk/ndk/21.1.6352462"
ANDROID_NDK_PATH="/Users/yaqi/Library/Android/sdk/ndk/24.0.8215888"
if [ ! -d "$ANDROID_NDK_PATH" ]; then
  read -p "Enter NDK path: " input_ndk_path
  ANDROID_NDK_PATH=${input_ndk_path:-$ANDROID_NDK_PATH}
fi

BUILD_FOLDER=build
rm -rf $BUILD_FOLDER
mkdir $BUILD_FOLDER

cmake \
  -G"Unix Makefiles" \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_TOOLCHAIN_FILE="$ANDROID_NDK_PATH/build/cmake/android.toolchain.cmake" \
  -DANDROID_NDK="$ANDROID_NDK_PATH" \
  -DOPERATING_SYSTEM="Android" \
  -DANDROID_PLATFORM=$ANDROID_PLATFORM \
  -DANDROID_ABI=$ANDROID_ABI \
  -DASSIMP_ANDROID_JNIIOSYSTEM=OFF \
  -DASSIMP_BUILD_TESTS=OFF \
  -DBUILD_SHARED_LIBS=OFF \
  -DASSIMP_BUILD_ALL_EXPORTERS_BY_DEFAULT=OFF \
  -DASSIMP_BUILD_ALL_IMPORTERS_BY_DEFAULT=OFF \
  -DASSIMP_INSTALL=OFF \
  -DASSIMP_INSTALL_PDB=OFF \
  -DASSIMP_BUILD_GLTF_IMPORTER=ON \
  -DASSIMP_BUILD_PLY_IMPORTER=ON \
  -DASSIMP_BUILD_3MF_IMPORTER=ON \
  -DASSIMP_BUILD_ASSIMP_TOOLS=OFF \
  -DASSIMP_BUILD_ZLIB=ON \
  -DCMAKE_CXX_FLAGS="$CXX_FLAGS" \
  -DCMAKE_C_FLAGS="$C_FLAGS" \ 
  -S "/Users/yaqi/Downloads/assimp-android" \
  -B "$BUILD_FOLDER"

cmake --build "$BUILD_FOLDER" -- -j 4

因为我只需要加载, 不如要导出, 所以都禁止了. 只编译了部分需要的格式, 大家可按需编译.
接下来是IOS的脚本

IOS 编译脚本

同样, 也是建一个.sh脚本, 然后执行脚本.

#!/bin/bash

#
# Written and maintained by the.arul@gmail.com (2014)
#

BUILD_DIR="./lib/iOS"

###################################
#        SDK Version
###################################
IOS_SDK_VERSION=$(xcodebuild -version -sdk iphoneos | grep SDKVersion | cut -f2 -d ':' | tr -d '[[:space:]]')
###################################

###################################
#        BUILD Configuration
###################################

BUILD_SHARED_LIBS=OFF
BUILD_TYPE=Release

################################################
#        Minimum iOS deployment target version
################################################
MIN_IOS_VERSION="10.0"

IOS_SDK_TARGET=$MIN_IOS_VERSION
XCODE_ROOT_DIR=$(xcode-select  --print-path)
TOOLCHAIN=$XCODE_ROOT_DIR/Toolchains/XcodeDefault.xctoolchain

CMAKE_C_COMPILER=$(xcrun -find cc)
CMAKE_CXX_COMPILER=$(xcrun -find c++)

BUILD_ARCHS_DEVICE="arm64e arm64 armv7s armv7"
BUILD_ARCHS_SIMULATOR="x86_64 i386"
BUILD_ARCHS_ALL=($BUILD_ARCHS_DEVICE $BUILD_ARCHS_SIMULATOR)

CPP_DEV_TARGET_LIST=(miphoneos-version-min mios-simulator-version-min)
CPP_DEV_TARGET=
CPP_STD_LIB_LIST=(libc++ libstdc++)
CPP_STD_LIB=
CPP_STD_LIST=(c++11 c++14)
CPP_STD=c++11

function join { local IFS="$1"; shift; echo "$*"; }

build_arch()
{
    IOS_SDK_DEVICE=iPhoneOS
    CPP_DEV_TARGET=${CPP_DEV_TARGET_LIST[0]}

    if [[ "$BUILD_ARCHS_SIMULATOR" =~ "$1" ]]
    then
        echo '[!] Target SDK set to SIMULATOR.'
        IOS_SDK_DEVICE=iPhoneSimulator
        CPP_DEV_TARGET=${CPP_DEV_TARGET_LIST[1]}
    else
        echo '[!] Target SDK set to DEVICE.'
    fi

    unset DEVROOT SDKROOT CFLAGS LDFLAGS CPPFLAGS CXXFLAGS CMAKE_CLI_INPUT
           
    export CC="$(xcrun -sdk iphoneos -find clang)"
    export CPP="$CC -E"
    export DEVROOT=$XCODE_ROOT_DIR/Platforms/$IOS_SDK_DEVICE.platform/Developer
    export SDKROOT=$DEVROOT/SDKs/$IOS_SDK_DEVICE$IOS_SDK_VERSION.sdk
    export CFLAGS="-arch $1 -pipe -no-cpp-precomp -isysroot $SDKROOT -I$SDKROOT/usr/include/ -miphoneos-version-min=$IOS_SDK_TARGET"
    if [[ "$BUILD_TYPE" =~ "Debug" ]]; then
      export CFLAGS="$CFLAGS -Og"
    else
         export CFLAGS="$CFLAGS -O3 -DNDEBUG"
    fi
    export LDFLAGS="-arch $1 -isysroot $SDKROOT -L$SDKROOT/usr/lib/"
    export CPPFLAGS="$CFLAGS"
    export CXXFLAGS="$CFLAGS -std=$CPP_STD"

    rm CMakeCache.txt
    
    CMAKE_CLI_INPUT="-DCMAKE_C_COMPILER=$CMAKE_C_COMPILER \
                     -DCMAKE_CXX_COMPILER=$CMAKE_CXX_COMPILER \
                     -DCMAKE_TOOLCHAIN_FILE=./port/iOS/IPHONEOS_$(echo $1 | tr '[:lower:]' '[:upper:]')_TOOLCHAIN.cmake \
                     -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
                     -DBUILD_SHARED_LIBS=$BUILD_SHARED_LIBS \
                     -DASSIMP_BUILD_ALL_IMPORTERS_BY_DEFAULT=OFF \
                     -DASSIMP_BUILD_GLTF_IMPORTER=ON \
                     -DASSIMP_BUILD_PLY_IMPORTER=ON \
                     -DASSIMP_BUILD_3MF_IMPORTER=ON \
                     -DASSIMP_BUILD_ALL_EXPORTERS_BY_DEFAULT=OFF \
                     -DASSIMP_NO_EXPORT=ON \
                     -DASSIMP_BUILD_TESTS=OFF \
                     -DASSIMP_BUILD_ASSIMP_TOOLS=OFF \
                     -DASSIMP_BUILD_SAMPLES=OFF \
                     -DASSIMP_BUILD_DOCS=OFF \
                     -DENABLE_BOOST_WORKAROUND=OFF \
                     -DASSIMP_BUILD_ZLIB=ON \
                     -DENABLE_TESTS=OFF"


    echo "[!] Running CMake with -G 'Unix Makefiles' $CMAKE_CLI_INPUT"
    
    cmake -G 'Unix Makefiles' ${CMAKE_CLI_INPUT}

    echo "[!] Building $1 library"

    xcrun -run make clean
    xcrun -run make assimp -j 8 -l    
    
    if [[ "$BUILD_SHARED_LIBS" =~ "ON" ]]; then
        echo "[!] Moving built dynamic libraries into: $BUILD_DIR/$1/"
        mv ./lib/*.dylib  $BUILD_DIR/$1/
    fi
    
    echo "[!] Moving built static libraries into: $BUILD_DIR/$1/"
    mv ./lib/*.a $BUILD_DIR/$1/    
}

echo "[!] $0 - assimp iOS build script"

CPP_STD_LIB=${CPP_STD_LIB_LIST[0]}
CPP_STD=${CPP_STD_LIST[0]}
DEPLOY_ARCHS=${BUILD_ARCHS_ALL[*]}
DEPLOY_FAT=1

for i in "$@"; do
    case $i in
    -s=*|--std=*)
        CPP_STD=`echo $i | sed 's/[-a-zA-Z0-9]*=//'`
        echo "[!] Selecting c++ standard: $CPP_STD"
    ;;
    -l=*|--stdlib=*)
        CPP_STD_LIB=`echo $i | sed 's/[-a-zA-Z0-9]*=//'`
        echo "[!] Selecting c++ std lib: $CPP_STD_LIB"
    ;;
    -a=*|--archs=*)
        DEPLOY_ARCHS=`echo $i | sed 's/[-a-zA-Z0-9]*=//'`
        echo "[!] Selecting architectures: $DEPLOY_ARCHS"
    ;;
    --debug)
        BUILD_TYPE=Debug        
        echo "[!] Selecting build type: Debug"
    ;;
    --shared-lib)
        BUILD_SHARED_LIBS=ON        
        echo "[!] Will generate dynamic libraries"
    ;;
    -n|--no-fat)
        DEPLOY_FAT=0
        echo "[!] Fat binary will not be created."
    ;;
    -h|--help)
        echo " - don't build fat library (--no-fat)."
        echo " - Include debug information and symbols, no compiler optimizations (--debug)."
        echo " - generate dynamic libraries rather than static ones (--shared-lib)."
        echo " - supported architectures (--archs):  $(echo $(join , ${BUILD_ARCHS_ALL[*]}) | sed 's/,/, /g')"
        echo " - supported C++ STD libs (--stdlib): $(echo $(join , ${CPP_STD_LIB_LIST[*]}) | sed 's/,/, /g')"
        echo " - supported C++ standards (--std): $(echo $(join , ${CPP_STD_LIST[*]}) | sed 's/,/, /g')"
        exit
    ;;
    *)
    ;;
    esac
done

cd ../../
rm -rf $BUILD_DIR

for ARCH_TARGET in $DEPLOY_ARCHS; do
    echo "Creating folder: $BUILD_DIR/$ARCH_TARGET"
    mkdir -p $BUILD_DIR/$ARCH_TARGET
    echo "Building for arc: $ARCH_TARGET" 
    build_arch $ARCH_TARGET
    #rm ./lib/libassimp.a
done


make_fat_static_or_shared_binary()
{
    LIB_NAME=$1
    LIPO_ARGS=''
    for ARCH_TARGET in $DEPLOY_ARCHS; do
        if [[ "$BUILD_SHARED_LIBS" =~ "ON" ]]; then
            LIPO_ARGS="$LIPO_ARGS-arch $ARCH_TARGET $BUILD_DIR/$ARCH_TARGET/$LIB_NAME.dylib "
        else
            LIPO_ARGS="$LIPO_ARGS-arch $ARCH_TARGET $BUILD_DIR/$ARCH_TARGET/$LIB_NAME.a "
        fi
    done
    if [[ "$BUILD_SHARED_LIBS" =~ "ON" ]]; then
        LIPO_ARGS="$LIPO_ARGS -create -output $BUILD_DIR/$LIB_NAME-fat.dylib"
    else
        LIPO_ARGS="$LIPO_ARGS -create -output $BUILD_DIR/$LIB_NAME-fat.a"
    fi
    lipo $LIPO_ARGS
}

make_fat_static_binary()
{
    LIB_NAME=$1
    LIPO_ARGS=''
    for ARCH_TARGET in $DEPLOY_ARCHS; do
        LIPO_ARGS="$LIPO_ARGS-arch $ARCH_TARGET $BUILD_DIR/$ARCH_TARGET/$LIB_NAME.a "
    done
    LIPO_ARGS="$LIPO_ARGS -create -output $BUILD_DIR/$LIB_NAME-fat.a"
    lipo $LIPO_ARGS
}

if [[ "$DEPLOY_FAT" -eq 1 ]]; then
    echo '[+] Creating fat binaries ...'
    
    if [[ "$BUILD_TYPE" =~ "Debug" ]]; then
        make_fat_static_or_shared_binary 'libassimpd'
    else
        make_fat_static_or_shared_binary 'libassimp'
    fi
    
    echo "[!] Done! The fat binaries can be found at $BUILD_DIR"
fi