source: network-game/graphics_library/common/shader.cpp@ ace001a

#include <stdio.h>
#include <string>
#include <vector>
#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;

#include <stdlib.h>
#include <string.h>

#include <GL/glew.h>

#include "shader.hpp"

GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){

        // Create the shaders
        GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
        GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);

        // Read the Vertex Shader code from the file
        std::string VertexShaderCode;
        std::ifstream VertexShaderStream(vertex_file_path, std::ios::in);
        if(VertexShaderStream.is_open()){
                std::string Line = "";
                while(getline(VertexShaderStream, Line))
                        VertexShaderCode += "\n" + Line;
                VertexShaderStream.close();
        }else{
                printf("Impossible to open %s. Are you in the right directory ? Don't forget to read the FAQ !\n", vertex_file_path);
                getchar();
                return 0;
        }

        // Read the Fragment Shader code from the file
        std::string FragmentShaderCode;
        std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in);
        if(FragmentShaderStream.is_open()){
                std::string Line = "";
                while(getline(FragmentShaderStream, Line))
                        FragmentShaderCode += "\n" + Line;
                FragmentShaderStream.close();
        }



        GLint Result = GL_FALSE;
        int InfoLogLength;



        // Compile Vertex Shader
        printf("Compiling shader : %s\n", vertex_file_path);
        char const * VertexSourcePointer = VertexShaderCode.c_str();
        glShaderSource(VertexShaderID, 1, &VertexSourcePointer , NULL);
        glCompileShader(VertexShaderID);

        // Check Vertex Shader
        glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
        glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
        if ( InfoLogLength > 0 ){
                std::vector<char> VertexShaderErrorMessage(InfoLogLength+1);
                glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
                printf("%s\n", &VertexShaderErrorMessage[0]);
        }



        // Compile Fragment Shader
        printf("Compiling shader : %s\n", fragment_file_path);
        char const * FragmentSourcePointer = FragmentShaderCode.c_str();
        glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer , NULL);
        glCompileShader(FragmentShaderID);

        // Check Fragment Shader
        glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
        glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
        if ( InfoLogLength > 0 ){
                std::vector<char> FragmentShaderErrorMessage(InfoLogLength+1);
                glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
                printf("%s\n", &FragmentShaderErrorMessage[0]);
        }



        // Link the program
        printf("Linking program\n");
        GLuint ProgramID = glCreateProgram();
        glAttachShader(ProgramID, VertexShaderID);
        glAttachShader(ProgramID, FragmentShaderID);
        glLinkProgram(ProgramID);

        // Check the program
        glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
        glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
        if ( InfoLogLength > 0 ){
                std::vector<char> ProgramErrorMessage(InfoLogLength+1);
                glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
                printf("%s\n", &ProgramErrorMessage[0]);
        }

        glDeleteShader(VertexShaderID);
        glDeleteShader(FragmentShaderID);

        return ProgramID;
}