https://www.khronos.org/opengl/wiki/Shader_Compilation#Example
Complete Source Code:
Shader.h
#ifndef SHADER_H
#define SHADER_H
#define GLEW_STATIC
#include <GL/glew.h>
#include <string>
#include <list>
std::string LoadTextFile(const std::string& filepath);
std::string ShaderTypeName(GLuint shader);
bool CompileShader(GLuint shader, const std::string& sourcecode);
std::string ShaderInfoLog(GLuint shader);
bool LinkProgram(GLuint program, const std::list<GLuint>& shaderlist);
std::string ProgramInfoLog(GLuint program);
#endif // SHADER_H
Shader.cpp
#include "Shader.h"
#include <iostream>
#include <fstream>
std::string LoadTextFile(const std::string & filepath)
{
std::string result(""), line;
std::fstream f(filepath.c_str(), std::ios::in);
while (f.good())
{
std::getline(f, line);
result += line + '\n';
}
return result;
}
std::string ShaderTypeName(GLuint shader)
{
if (glIsShader(shader))
{
GLint type = 0;
glGetShaderiv(shader, GL_SHADER_TYPE, &type);
if (type == GL_VERTEX_SHADER)
return "Vertex Shader";
if (type == GL_TESS_CONTROL_SHADER)
return "Tessellation Control Shader";
if (type == GL_TESS_EVALUATION_SHADER)
return "Tessellation Evaluation Shader";
if (type == GL_GEOMETRY_SHADER)
return "Geometry Shader";
if (type == GL_FRAGMENT_SHADER)
return "Fragment Shader";
if (type == GL_COMPUTE_SHADER)
return "Compute Shader";
}
return "invalid shader";
}
bool CompileShader(GLuint shader, const std::string& sourcecode)
{
if (!glIsShader(shader))
{
std::cout << "ERROR: shader compilation failed, no valid shader specified" << std::endl;
return false;
}
if (sourcecode.empty())
{
std::cout << "ERROR: shader compilation failed, no source code specified (" << ShaderTypeName(shader) << ")" << std::endl;
return false;
}
const char* sourcearray[] = { sourcecode.c_str() };
glShaderSource(shader, 1, sourcearray, NULL);
glCompileShader(shader);
// check compile status
GLint status = 0;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
// successfully compiled shader
if (status == GL_TRUE)
return true;
// show compile errors
std::cout << "ERROR: shader compilation failed (" << ShaderTypeName(shader) << ")" << std::endl << ShaderInfoLog(shader) << std::endl;
return false;
}
std::string ShaderInfoLog(GLuint shader)
{
if (glIsShader(shader))
{
GLint logsize = 0;
GLchar infolog[1024] = { 0 };
glGetShaderInfoLog(shader, 1024, &logsize, infolog);
return std::string(infolog);
}
return "invalid shader";
}
bool LinkProgram(GLuint program, const std::list<GLuint>& shaderlist)
{
if (!glIsProgram(program))
{
std::cout << "ERROR: shader linking failed, no valid program specified" << std::endl;
return false;
}
// attach all shaders to the program
for (std::list<GLuint>::const_iterator it = shaderlist.begin(); it != shaderlist.end(); it++)
{
if (glIsShader(*it))
glAttachShader(program, *it);
}
// link program
glLinkProgram(program);
// detach all shaders again
for (std::list<GLuint>::const_iterator it = shaderlist.begin(); it != shaderlist.end(); it++)
{
if (glIsShader(*it))
glDetachShader(program, *it);
}
GLint status = 0;
glGetProgramiv(program, GL_LINK_STATUS, &status);
// successfully linked program
if (status == GL_TRUE)
return true;
// show link errors
std::cout << "ERROR: shader linking failed" << std::endl << ProgramInfoLog(program) << std::endl;
return false;
}
std::string ProgramInfoLog(GLuint program)
{
if (glIsProgram(program))
{
GLint logsize = 0;
GLchar infolog[1024] = { 0 };
glGetProgramInfoLog(program, 1024, &logsize, infolog);
return std::string(infolog);
}
return "invalid program";
}