如何在c++中使用maya-api对对象应用颜色和着色

Question

我想知道如何在c++中对对象应用颜色和着色(使用maya-api映射2D纹理)，以下是我的代码：

MString MNEUT_FILE("G:/repos_cpp/data/eye_base.obj");
MGlobal::executeCommand(MString("file -import -namespace \"EYETemp\" -mergeNamespacesOnClash true") + "\"" + MNEUT_FILE + "\"");
MGlobal::executeCommand(MString("select \"EYETemp:*\""));
MGlobal::executeCommand(MString("rename ") + "eyeNeutral");

stat = MGlobal::executeCommand(MString("shadingNode -asShader lambert -name eyeball"));
stat = MGlobal::executeCommand(MString("sets -renderable true -noSurfaceShader true -empty -name lambert3SG"));
//stat = MGlobal::executeCommand(MString("defaultNavigation -connectToExisting -source eyeball -destination lambert3SG"));
stat = MGlobal::executeCommand(MString("connectAttr -f eyeball.outColor lambert3SG.surfaceShader"));
stat = MGlobal::executeCommand(MString("shadingNode -asTexture file -name eyeball_TGA"));
stat = MGlobal::executeCommand(MString("connectAttr -f eyeball_TGA.outColor eyeball.color"));
stat = MGlobal::executeCommand(MString("setAttr -type \"string\" eyeball_TGA.fileTextureName \"G:/repos_cpp/data/eyeball.TGA\""));
MGlobal::executeCommand(MString("select -r eyeNeutralShape"));
stat = MGlobal::executeCommand(MString("hyperShade -assign lambert3SG"));
if (!stat)
{
    cout << "error::8\n";
}
stat = MGlobal::executeCommand(MString("sets -e -fe lambert3SG eyeNeutralShape"));
if (!stat)
{
    cout << "error::9\n";
}

当我运行这段代码时，"error::8“总是存在的！你能告诉我怎么解决它吗？非常感谢！

Answer 1

您只检查最后一个MGlobal::executeCommand的状态，所以您无法知道它实际上失败的地方。您也不需要检查错误文本来获取错误的解释。

考虑制作一个用于检查所有调用的包装器：

#include <stdexcept>

MCommandResult MayaCmd(MString cmd) {
    MCommandResult retval;
    std::cout << "Executing MayaCmd: " << cmd << '\n';
    auto stat = MGlobal::executeCommand(cmd, retval);
    if(!stat) throw std::runtime_error(stat.errorString().asChar()); // or asUTF8()
    return retval;
}

然后，您应该能够轻而易举地执行您的命令，并在异常发生时立即获得一个具有解释的异常。

示例：

try {
    MayaCmd(MString("file -import -namespace \"EYETemp\" -mergeNamespacesOnClash true") + "\"" + MNEUT_FILE + "\"");
    MayaCmd("select \"EYETemp:*\"");
    MayaCmd("rename eyeNeutral");

    MayaCmd("shadingNode -asShader lambert -name eyeball");
    MayaCmd("sets -renderable true -noSurfaceShader true -empty -name lambert3SG");
    //MayaCmd("defaultNavigation -connectToExisting -source eyeball -destination lambert3SG");
    MayaCmd("connectAttr -f eyeball.outColor lambert3SG.surfaceShader");
    MayaCmd("shadingNode -asTexture file -name eyeball_TGA");
    MayaCmd("connectAttr -f eyeball_TGA.outColor eyeball.color");
    MayaCmd("setAttr -type \"string\" eyeball_TGA.fileTextureName \"G:/repos_cpp/data/eyeball.TGA\"");
    MayaCmd("select -r eyeNeutralShape");
    MayaCmd("hyperShade -assign lambert3SG");
    MayaCmd("sets -e -fe lambert3SG eyeNeutralShape");
}
catch(const std::exception& ex) {
    std::cout << "Exception: " << ex.what() << '\n';
}

我还怀疑您应该与hyperShade -assign一起使用的名称是由前面的某个命令返回的名称，可能是shadingNode。示例：

auto ShaderNode = MayaCmd("shadingNode ...").stringResult();
...
MayaCmd("hyperShade -assign " + ShaderNode);