Shader.cpp

#include <GL/glew.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <GLFW/glfw3.h>

#include "Shader.h"

#include "stdio.h"
#include <string>
#include <string.h>
#include <fstream>
#include <vector>

GLuint buildShader(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\n", vertex_file_path);
        exit(-1);
    }

    // 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 resultString;


    // 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, &resultString);
    if ( resultString > 0 && Result != GL_TRUE){
        std::vector<char> VertexShaderErrorMessage(resultString+1);
        glGetShaderInfoLog(VertexShaderID, resultString, 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, &resultString);
    if ( resultString > 0 && Result != GL_TRUE){
        std::vector<char> FragmentShaderErrorMessage(resultString+1);
        glGetShaderInfoLog(FragmentShaderID, resultString, NULL, &FragmentShaderErrorMessage[0]);
        printf("%s\n", &FragmentShaderErrorMessage[0]);
        exit(-1);
    }

    // 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, &resultString);
    if ( resultString > 0 && Result != GL_TRUE){
        std::vector<char> ProgramErrorMessage(resultString+1);
        glGetProgramInfoLog(ProgramID, resultString, NULL, &ProgramErrorMessage[0]);
        printf("%s\n", &ProgramErrorMessage[0]);
        exit(-1);
    }

    glDetachShader(ProgramID, VertexShaderID);
    glDetachShader(ProgramID, FragmentShaderID);

    glDeleteShader(VertexShaderID);
    glDeleteShader(FragmentShaderID);

    return ProgramID;
}