Problem_OpenGL.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
//-----------------------------SHADERS--------------------------------------------------------------------
static unsigned int CompileShader(unsigned int type, const std::string& source)
{
    unsigned int id = glCreateShader(type);
    const char* src = source.c_str();
    glShaderSource(id, 1, &src, nullptr);
    glCompileShader(id);

    int result;
    glGetShaderiv(id, GL_COMPILE_STATUS, &result);
    if (result == GL_FALSE)
    {
        int length;
        glGetShaderiv(id,GL_INFO_LOG_LENGTH,&length);
        char* message=(char*)alloca(length *sizeof(char));
        glGetShaderInfoLog(id,length,&length,message);
        std::cout<<"Failed to compile shader"<<std::endl;
        std::cout<<message<<std::endl;
        glDeleteShader(id);
        return(0);
        
    }
    std::cout << id<< std::endl;
    return id;
}

static unsigned int CreateShader(const std::string& vertexShader, const std::string& fragmentShader)
{
    unsigned int program = glCreateProgram();
    unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
    unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);

    glAttachShader(program, vs);
    glAttachShader(program, fs);
    glLinkProgram(program);
    glValidateProgram(program);

    glDeleteShader(vs);
    glDeleteShader(fs);
    std::cout << program<< std::endl;
    return program;
}



//-------------------------------------MAIN---------------------------------------------------

int main(void)
{

//-------------------------INICJALIZACJA-I-TWORZENIE-OKNA------------------------

    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
    {
        std::cout<<"ERROR!"<<std::endl;
        return -1;
    }

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        std::cout<<"Error!"<<std::endl;
        glfwTerminate();
        return -1;
    }

    /* Make the window's context current */
    glfwMakeContextCurrent(window);

    if (glewInit() != GLEW_OK)
    {
        std::cout << "Error!"<< std::endl;
        return -1;
    };


//------------------------------------TWORZENIE-WYPELNIANIE-BUFORA----------


    float positions[] = {
    -0.5f,-0.5f,
     0.0f, 0.5f,
     0.5f,-0.5f};

    GLuint buffer;  // zmienna przechowująca id buforu
    glGenBuffers(1, &buffer);   //Tworzenie buforu, podanie jego nazwy do zmiennej buffer
    glBindBuffer(GL_ARRAY_BUFFER, buffer);  // Połączenie buforu z GL_ARRAY_BUFFER
    glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);    //spisanie danych do buforu

    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);

//------------------------------------SHADERY--------------------------------
    std::string vertexShader=
        "attribute vec3 position;\n"
        "void main ()\n"
        "{\n"
        "    gl_Position = vec4(position,1.0);\n"
        "}";

    std::string fragmentShader=
        "void main()\n"
        "{\n"
        "   gl_FragColor=vec4(1.0,0.0,0.0,1.0);\n"
        "}\n";

    std::cout<<fragmentShader<<std::endl;

    unsigned int shader=CreateShader(vertexShader,fragmentShader);
    glUseProgram(shader);

    while (!glfwWindowShouldClose(window))
    {
        glClearColor(1, 1, 1, 1);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    glfwTerminate();
    return 0;
}