为什么应该没有错误，为什么会出现链接错误

Question

我是Java开发人员，最近改用了C ++。我一直在尝试制作一些OpenGL程序，但遇到了问题。每当我尝试编译着色器程序时，都会出现链接错误。这是：

ERROR::SHADER::PROGRAML::LINKING_ERROR
Link info
---------
error: "TexCoord" not declared as an output from the previous stage

这里是着色器文件：

顶点：

#version 440 core

layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;

out vec3 ourColor;
out vec2 TexCoord;

void main()
{
    gl_Position = vec4(aPos, 1.0);
    ourColor = aColor;
    TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}

片段

#version 440 core

out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

// texture sampler
uniform sampler2D texture1;

void main()
{
    FragColor = texture(texture1, TexCoord);
}

这是着色器的创建：

int success;
char infoLog[512];

const char* vertexSource;
const char* fragmentSource;

// Load in shader source

std::ifstream inFile;

inFile.open(vertexPath);

std::string temp = "";
std::string source = "";

if (inFile.is_open())
{
    while (std::getline(inFile, temp))
        source += temp + "\n";
}
else
{
    std::cout << "ERROR::SHADER::VERTEX::COULD_NOT_OPEN_SOURCE_FILE" << std::endl;
}

inFile.close();

vertexSource = source.c_str();

temp = "";
source = "";

inFile.open(fragmentPath);

if (inFile.is_open())
{
    while (std::getline(inFile, temp))
        source += temp + "\n";
}
else
{
    std::cout << "ERROR::SHADER::FRAGMENT::COULD_NOT_OPEN_SOURCE_FILE" << std::endl;
}

inFile.close();

fragmentSource = source.c_str();

unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexSource, nullptr);
glCompileShader(vertexShader);

glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
    glGetShaderInfoLog(vertexShader, 512, nullptr, infoLog);
    std::cout << "ERROR::SHADER::VERTEX::COULD_NOT_COMPILE\n" << infoLog << std::endl;
}

unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentSource, nullptr);
glCompileShader(fragmentShader);

glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
    glGetShaderInfoLog(fragmentShader, 512, nullptr, infoLog);
    std::cout << "ERROR::SHADER::FRAGMENT::COULD_NOT_COMPILE\n" << infoLog << std::endl;
}

// Program

ID = glCreateProgram();
glAttachShader(ID, vertexShader);
glAttachShader(ID, fragmentShader);
glLinkProgram(ID);

glGetProgramiv(ID, GL_LINK_STATUS, &success);
if (!success)
{
    glGetProgramInfoLog(ID, 512, nullptr, infoLog);
    std::cout << "ERROR::SHADER::PROGRAML::LINKING_ERROR\n" << infoLog << std::endl;
}

glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
glUseProgram(0);

据我所知，如果我要链接的两个变量的名称或类型不同，而它们却是相同的，我应该只会收到此错误。我只是不明白。

谢谢。

Answer 1

您基本上有...

std::string source;
const char *vertexSource;
const char *fragmentSource;

...read into source...

vertexSource = source.c_str();

...read into source...

fragmentSource = source.c_str();

vertexSource中存储的指针将因第二次读取source而无效。从documentation

从c_str（）获得的指针可能被以下方法无效：

• 将对字符串的非常量引用传递给任何标准库函数，或
• 在字符串上调用非常量成员函数，不包括operator []，at（），front（），back（），begin（），rbegin（），end（）和rend（）。