shaders.cpp

#include <iostream>

#include <fstream>

#include <string.h>

#include <GL/glut.h>

#include <GL/glext.h>

using namespace std;

string textFileRead(const char * filename) {
    string str, ret = "";
    ifstream in ; in .open(filename);
    if ( in .is_open()) {
        getline( in , str);
        while ( in ) {
            ret += str + "\n";
            getline( in , str);
        }
        return ret;
    } else {
        cerr << "Unable to Open File " << filename << "\n";
        throw 2;
    }
}

void programerrors(const GLint program) {
    GLint length;
    GLchar * log;
    glGetProgramiv(program, GL_INFO_LOG_LENGTH, & length);
    log = new GLchar[length + 1];
    glGetProgramInfoLog(program, length, & length, log);
    cout << "Compile Error, Log Below\n" << log << "\n";
    delete[] log;
}
void shadererrors(const GLint shader) {
    GLint length;
    GLchar * log;
    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, & length);
    log = new GLchar[length + 1];
    glGetShaderInfoLog(shader, length, & length, log);
    cout << "Compile Error, Log Below\n" << log << "\n";
    delete[] log;
}

GLuint initshaders(GLenum type,
    const char * filename) {

    GLuint shader = glCreateShader(type);
    GLint compiled;
    string str = textFileRead(filename);
    GLchar * cstr = new GLchar[str.size() + 1];
    const GLchar * cstr2 = cstr; // Weirdness to get a const char
    strcpy(cstr, str.c_str());
    glShaderSource(shader, 1, & cstr2, NULL);
    glCompileShader(shader);
    glGetShaderiv(shader, GL_COMPILE_STATUS, & compiled);
    if (!compiled) {
        shadererrors(shader);
        throw 3;
    }
    return shader;
}

GLuint initprogram(GLuint vertexshader, GLuint fragmentshader) {
    GLuint program = glCreateProgram();
    GLint linked;
    glAttachShader(program, vertexshader);
    glAttachShader(program, fragmentshader);
    glLinkProgram(program);
    glGetProgramiv(program, GL_LINK_STATUS, & linked);
    if (linked) glUseProgram(program);
    else {
        programerrors(program);
        throw 4;
    }
    return program;
}