#include "Shader.h"

Shader::Shader(string  vFile, string  fFile, string  gFile) {
     program = glCreateProgram();
     objects[SHADER_VERTEX] = GenerateShader(vFile, GL_VERTEX_SHADER);
     objects[SHADER_FRAGMENT] = GenerateShader(fFile, GL_FRAGMENT_SHADER);
     objects[SHADER_GEOMETRY] = 0;
     if (!gFile.empty()) {
        objects[SHADER_GEOMETRY] = GenerateShader(gFile,
                                                           GL_GEOMETRY_SHADER);
        glAttachShader(program, objects[SHADER_GEOMETRY]);
	}
     glAttachShader(program, objects[SHADER_VERTEX]);
    glAttachShader(program, objects[SHADER_FRAGMENT]);

     SetDefaultAttributes();
}
Shader ::~Shader(void) {
     for (int i = 0; i < 3; ++i) {
        glDetachShader(program, objects[i]);
        glDeleteShader(objects[i]);

	}
     glDeleteProgram(program);
}
GLuint    Shader::GenerateShader(string  from, GLenum  type) {
     cout << "Compiling  Shader ..." << endl;

     string  load;
     if (!LoadShaderFile(from, load)) {
        cout << "Compiling  failed!" << endl;
        loadFailed = true;
        return  0;
	}

     GLuint  shader = glCreateShader(type);

     const  char *chars = load.c_str();
     glShaderSource(shader, 1, &chars, NULL);
     glCompileShader(shader);

     GLint  status;
     glGetShaderiv(shader, GL_COMPILE_STATUS, &status);

     if (status == GL_FALSE) {
        cout << "Compiling  failed!" << endl;
        char  error[512];
        glGetInfoLogARB(shader, sizeof(error), NULL, error);
        cout << error;
        loadFailed = true;
        return  0;
	}
     cout << "Compiling  success!" << endl << endl;
     loadFailed = false;
     return  shader;
}
bool   Shader::LoadShaderFile(string  from, string &into) {
     ifstream  file;
     string        temp;

     cout << "Loading  shader  text  from " << from << endl << endl;

     file.open(from.c_str());
     if (!file.is_open()) {
        cout << "File  does  not  exist!" << endl;
        return  false;

	}
     while (!file.eof()) {
        getline(file, temp);
        into += temp + "\n";
	}

     file.close();
     cout << into << endl << endl;
     cout << "Loaded  shader  text!" << endl << endl;
     return  true;
}

bool  Shader::LinkProgram() {
     if (loadFailed) {
        return  false;
	}
     glLinkProgram(program);

     GLint  code;
     glGetProgramiv(program, GL_LINK_STATUS, &code);
     return  code == GL_TRUE ? true : false;
}

void   Shader::SetDefaultAttributes() {
	glBindAttribLocation(program, VERTEX_BUFFER, "position");
	glBindAttribLocation(program, COLOUR_BUFFER, "colour");
	glBindAttribLocation(program, NORMAL_BUFFER, "normal");
	glBindAttribLocation(program, TANGENT_BUFFER, "tangent");
	glBindAttribLocation(program, TEXTURE_BUFFER, "texCoord");
}