Window.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "Game.h"
using namespace std;

GLFWwindow* glfwWindow;
Window window;

float positions[6] = {
    -0.5F, -0.5F,
     0.0F,  0.5F,
     0.5F, -0.5F
};

static unsigned int CompileShader(unsigned int type, const 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[length];
        glGetShaderInfoLog(id, length, &length, message);
        cout << "Failed to compile" << (type == GL_VERTEX_SHADER ? " vertex" : " fragment") << " shader!" << endl;
        cout << message << endl;
        glDeleteShader(id);
        return 0;
    }

    return id;
}

static unsigned int CreateShader(const string& vertexShader, const 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);

    return program;
}

void createWindow(Window newWindow){
    window = newWindow;
    run();
}

void run() {
    init();
    cout << "Hello " << glGetString(GL_VERSION) << " !" << endl;
    loop();
    glfwDestroyWindow(glfwWindow);
    glfwTerminate();
}

int init() {
    /* Initialize the library */
    if (!glfwInit()) {
        cout << "Unable to initialize GLFW" << endl;
        return -1;
    }
    glfwDefaultWindowHints();
    glfwWindowHint(GLFW_RESIZABLE, window.resizable ? GLFW_TRUE : GLFW_FALSE);
    glfwWindowHint(GLFW_FLOATING, GLFW_TRUE);
    glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_FALSE);
    glfwWindowHint(GLFW_DECORATED, GLFW_TRUE);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    /* Create a windowed mode window and its OpenGL context */
    glfwWindow = glfwCreateWindow(
            window.fullScreen ? 1366 : window.width/*640*/,
            window.fullScreen ? 768 : window.height/*480*/,
            window.title,
            window.fullScreen ? glfwGetPrimaryMonitor() : NULL,
            NULL
        );
    if (!glfwWindow){
        glfwTerminate();
        cout << "Failed to create the GLFW window" << endl;
        return -1;
    }
    // Make the OpenGL context current
    glfwMakeContextCurrent(glfwWindow);
    if(glewInit() != GLEW_OK)
        cout << "Error" << endl;
    // Enable v-sync
    glfwSwapInterval(1);
    // Make the window visible
    glfwShowWindow(glfwWindow);
    return 0;
}

void loop() {
    unsigned int buffer;
    glGenBuffers(1, &buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float), positions, GL_STATIC_DRAW);

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

    string vertexShader =
        "#version 330\n"
        "layout(location=0) in vec4 position;\n"
        "void main() {\n"
        "   gl_Position = position;\n"
        "}";
    string fragmentShader =
        "#version 330\n"
        "layout(location=0) out vec4 color;\n"
        "void main() {\n"
        "   color = vec4(1.0, 0.0, 0.0, 1.0);\n"
        "}";

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

    double previousTime = glfwGetTime();
    int frameCount = 0;
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    while (!glfwWindowShouldClose(glfwWindow)) {
        double currentTime = glfwGetTime();
        frameCount++;
        if (currentTime - previousTime >= 1.0) {
            string title = window.title;
            title = title.append(" | ");
            glfwSetWindowTitle(glfwWindow, title.append(to_string(frameCount)).c_str());
            frameCount = 0;
            previousTime = currentTime;
        }
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer

        glDrawArrays(GL_TRIANGLES, 0, 3);
//        glBegin(GL_TRIANGLES);
//        glVertex2f(-0.5F, -0.5F);
//        glVertex2f(0.0F, 0.5F);
//        glVertex2f(0.5F, -0.5F);
//        glEnd();

        glfwSwapBuffers(glfwWindow); // swap the color buffers
        // Poll for window events. The key callback above will only be
        // invoked during this call.
        glfwPollEvents();
    }
}