将着色器附加到程序

问题描述

将已编译的着色器附加到程序时出现OpenGL错误＃1281。 这是顶点着色器代码：

#version 330 core

layout(location = 0) in vec2 position;

void main(){
  gl_Position = vec4(position,0.0f,0.0f);
}

这是片段着色器代码：

#version 330 core

out vec4 color;

void main(){
  color = vec4(1.0f,1.0f);
}

以下是创建着色器（程序）的方法：

Shader::Shader(std::string vsfilename,std::string fsfilename)
  :program(glCreateProgram()) {
  const char* vscode = fileToString(vsfilename.c_str());
  const char* fscode = fileToString(fsfilename.c_str());

  unsigned int vs,fs;

  //Compiling Vertex shader
  vs = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vs,1,&vscode,NULL);
  glCompileShader(vs);

  int result;
  glGetShaderiv(vs,GL_COMPILE_STATUS,&result);
  if(!result){
    glGetShaderiv(vs,GL_INFO_LOG_LENGTH,&result);

    char* infolog = (char*) malloc(result*sizeof(char));
    glGetShaderInfoLog(vs,result,&result,infolog);

    std::cout<<"Problem with vs compilation"<<std::endl;
    std::cout<<infolog<<std::endl;

    free((void*)infolog);
    glDeleteShader(vs);
    vs = 0;
  }

  fs = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fs,&fscode,NULL);
  glCompileShader(fs);

  glGetShaderiv(fs,&result);
  if(!result){
    glGetShaderiv(fs,&result);

    char* infolog = (char*) malloc(result*sizeof(char));
    glGetShaderInfoLog(fs,infolog);

    std::cout<<"Problem with fs compilation"<<std::endl;
    std::cout<<infolog<<std::endl;

    free((void*)infolog);
    glDeleteShader(fs);
    fs = 0;
  }

  glAttachShader(vs,program);
  int error;
  do{
    error = glGetError(); //error 1281
    std::cout<<error<<std::endl;
  } while(error != 0);
  glAttachShader(fs,program);

  glLinkProgram(program);
  glValidateProgram(program);

  glDetachShader(vs,program);
  glDetachShader(fs,program);
  glDeleteShader(vs);
  glDeleteShader(fs);
  free((void*)vscode);
  free((void*)fscode);
}

解决方法

错误1281表示INVALID_VALUE，如果程序或着色器不是OpenGL生成的值，则会生成该错误。

glAttachShader的第一个参数是程序，第二个参数是着色器：

glAttachShader(vs,program);

glAttachShader(program,vs);