Ubuntu环境编译Blender遇类型转换错误求助（49%失败）

问题背景 #

按照Blender官方Ubuntu编译指南操作，编译到49%时失败，已更新Python和gcc，作为Ubuntu新手寻求解决办法。

错误日志 #

/home/istmadmin/blender-git/blender/source/blender/blenlib/intern/index_mask.cc: In function ‘void blender::index_mask::inverted_indices_to_segments(blender::index_mask::IndexMaskSegment, blender::LinearAllocator<>&, blender::Vector<blender::OffsetSpan<long int, short int>, 16>&)’:
/home/istmadmin/blender-git/blender/source/blender/blenlib/intern/index_mask.cc:384:60: error: conversion from ‘int’ to ‘int16_t’ {aka ‘short int’} may change value [-Werror=conversion]
  384 |     const int16_t gap_first = indices[size_before_gap - 1] + 1;
/home/istmadmin/blender-git/blender/source/blender/blenlib/intern/index_mask.cc:386:35: error: conversion from ‘int’ to ‘int16_t’ {aka ‘short int’} may change value [-Werror=conversion]
  386 |     const int16_t gap_size = next - gap_first;
      |                              ~~^~~~
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_3_4.cc.o
At global scope:
cc1plus: warning: unrecognized command line option ‘-Wno-stringop-overread’
cc1plus: some warnings being treated as errors
make[3]: * [source/blender/blenlib/CMakeFiles/bf_blenlib.dir/build.make:817: source/blender/blenlib/CMakeFiles/bf_blenlib.dir/intern/index_mask.cc.o] Error 1
make[2]: * [CMakeFiles/Makefile2:6442: source/blender/blenlib/CMakeFiles/bf_blenlib.dir/all] Error 2
make[2]: * Waiting for unfinished jobs....
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_3_6.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_3_9.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_3_d.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_3.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_4.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_6.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_8.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_9.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_4_d.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_2_d_d.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_3_3_3.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_4_4_2.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_4_4_3.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_4_4_4.cc.o
[ 49%] Building CXX object extern/ceres/CMakeFiles/extern_ceres.dir/internal/ceres/generated/schur_eliminator_4_4_d.cc.o
[ 49%] Linking CXX static library ../../lib/libextern_ceres.a
[ 49%] Built target extern_ceres
make[1]: * [Makefile:163: all] Error 2
make: * [GNUmakefile:368: all] Error 2

解决方法 #

• 临时绕过编译警告：在CMake配置阶段添加参数，关闭类型转换警告作为错误。执行以下命令：

  cmake -DCMAKE_CXX_FLAGS="-Wno-error=conversion" ../blender
  

  随后重新启动编译：

  make -j$(nproc)
  

• 修复源码类型转换：直接修改报错的源码行，添加显式类型转换：
  1. 打开报错文件：

     nano /home/istmadmin/blender-git/blender/source/blender/blenlib/intern/index_mask.cc
     

  2. 将第384行修改为：

     const int16_t gap_first = static_cast<int16_t>(indices[size_before_gap - 1] + 1);
     

  3. 将第386行修改为：

     const int16_t gap_size = static_cast<int16_t>(next - gap_first);
     

  4. 保存文件后重新编译。
• 检查gcc版本兼容性：确认gcc版本在Blender官方支持范围内，若当前版本过高，可尝试降级到官方推荐版本（如gcc 11或12）。

内容的提问来源于Stack Exchange，提问作者Samet Kocbay