c++ - 在我的 for 循环中，如何将索引更改为字符串？

Question

我有这段不断重复的代码。

g_materialAmbientIndex[0] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[0].ambient");
g_materialDiffuseIndex[0] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[0].diffuse");
g_materialSpecularIndex[0] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[0].specular");

g_materialAmbientIndex[1] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[1].ambient");
g_materialDiffuseIndex[1] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[1].diffuse");
g_materialSpecularIndex[1] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[1].specular");

g_materialAmbientIndex[2] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[2].ambient");
g_materialDiffuseIndex[2] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[2].diffuse");
g_materialSpecularIndex[2] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[2].specular");

我想将它放入一个 for 循环中，但我遇到了字符串参数的问题。下面是我的功能。我不断收到一条错误消息:

no suitable conversion func from "std::basic_string....." to "const GLchar*" exists

for (int i = 0; i < MAX_MATERIALS; i++)
{
    stringstream ss;
    ss << i;
    string str = ss.str();

    g_materialAmbientIndex[i] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[" + str + "].ambient");
    g_materialDiffuseIndex[i] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[" + str + "].diffuse");
    g_materialSpecularIndex[i] = glGetUniformLocation(g_shaderProgramID, "uMaterialProperties[" + str + "].specular");
}

Answer 1

错误消息会告诉您需要知道的一切:

不存在从“std::basic_string.....”到“const GLchar*”的合适转换函数

因此该方法不知道如何处理 std::string - 它需要一个 GLchar*。您应该尝试的第一件事是通过 str.c_str() 的常规 char*。