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Anttweakbar glfw3 OpenGL 3.2 no drawing

I'm having trouble using AntTweakBar with modern opengl (dynamic pipeline) and glfw3. I use some shaders, and I'm sure the problem is with the camera or shaders. Keyboard shortcuts work, but I don't have a fancy window that I should have :(

Here is the source

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#if __cplusplus <= 199711L
#define nullptr NULL
#endif
#include <cmath>
#include <AntTweakBar.h>

const GLchar *vxShaderSrc = R"(
#version 150 core

in vec2 position;
in vec4 color;
uniform vec2 offset;

out vec4 Color;

void main()
{
    Color = color;
    gl_Position = vec4(position+offset, 0.0, 1.0);
}
)";

const GLchar *fragShaderSrc = R"(
#version 150 core
in vec4 Color;
out vec4 outColor;

void main()
{
    outColor = Color;
}
)";

inline void TwEventMouseButtonGLFW3(GLFWwindow* window, int button, int action, int mods)
{TwEventMouseButtonGLFW(button, action);}
inline void TwEventMousePosGLFW3(GLFWwindow* window, double xpos, double ypos)
{TwMouseMotion(int(xpos), int(ypos));}
inline void TwEventMouseWheelGLFW3(GLFWwindow* window, double xoffset, double yoffset)
{TwEventMouseWheelGLFW(yoffset);}
inline void TwEventKeyGLFW3(GLFWwindow* window, int key, int scancode, int action, int mods)
{TwEventKeyGLFW(key, action);}
inline void TwEventCharGLFW3(GLFWwindow* window, int codepoint)
{TwEventCharGLFW(codepoint, GLFW_PRESS);}
inline void TwWindowSizeGLFW3(GLFWwindow* window, int width, int height)
{TwWindowSize(width, height);}


int main()
{
    if (!glfwInit()) {
        std::cerr<<"Error initializing glfw...\n";
        return 1;
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
#ifdef __APPLE__ // TODO is it ok to use it on Windows and Linux?
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    glfwWindowHint(GLFW_RESIZABLE, GL_TRUE);

    TwBar *bar;
    GLFWwindow* window = glfwCreateWindow(800, 600, "OpenGL", nullptr, nullptr); // Windowed
    if (!window) {
        std::cerr<<"Error creating window...\n";
        glfwTerminate();
        return 2;
    }
    glfwMakeContextCurrent(window);
    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_NORMAL); // can be GLFW_CURSOR_HIDDEN

     // Initialize AntTweakBar
    TwInit(TW_OPENGL, NULL);

    // Create a tweak bar
    bar = TwNewBar("TweakBar");
    TwWindowSize(800, 600);
    int wire = 0;
    float bgColor[] = { 0.1f, 0.2f, 0.4f };
    TwDefine(" GLOBAL help='This example shows how to integrate AntTweakBar with GLFW and OpenGL.' "); // Message added to the help bar.
    // Add 'wire' to 'bar': it is a modifable variable of type TW_TYPE_BOOL32 (32 bits boolean). Its key shortcut is [w].
    TwAddVarRW(bar, "wire", TW_TYPE_BOOL32, &wire, 
               " label='Wireframe mode' key=w help='Toggle wireframe display mode.' ");
    // Add 'bgColor' to 'bar': it is a modifable variable of type TW_TYPE_COLOR3F (3 floats color)
    TwAddVarRW(bar, "bgColor", TW_TYPE_COLOR3F, &bgColor, " label='Background color' ");

    // Set GLFW event callbacks
    // - Redirect window size changes to the callback function WindowSizeCB
    glfwSetWindowSizeCallback(window, (GLFWwindowposfun)TwWindowSizeGLFW3);

    glfwSetMouseButtonCallback(window, (GLFWmousebuttonfun)TwEventMouseButtonGLFW3);
    glfwSetCursorPosCallback(window, (GLFWcursorposfun)TwEventMousePosGLFW3);
    glfwSetScrollCallback(window, (GLFWscrollfun)TwEventMouseWheelGLFW3);
    glfwSetKeyCallback(window, (GLFWkeyfun)TwEventKeyGLFW3);
    glfwSetCharCallback(window, (GLFWcharfun)TwEventCharGLFW3);


    glewExperimental = GL_TRUE;
    if (glewInit() != GLEW_NO_ERROR) {
        std::cerr<<"Error initializing GLEW...\n";
        glfwTerminate();
        return 1;
    }

    GLuint vao;
    glGenVertexArrays(1, &vao);
    std::cout << "Created vertex array with id " << vao << "\n";
    glBindVertexArray(vao); // save the calls of vertexattribpointer and others, MUST BE before the EBO

    GLuint vbo;
    glGenBuffers(1, &vbo); // Generate 1 buffer
    std::cout << "Created Arrray with id " << vbo << "\n";
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    GLfloat vertices[] = {
        -0.5f, -0.5f, 1.f, 1.f, 1.0f, 1.f,
        -0.5f,  0.5f, 1.0f, 0.0f, 0.0f, 1.f,
        0.5f, -0.5f, 0.0f, 0.f, 1.0f, 1.f,
        0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.f,
        // some extra for elements testing
        0.0f,  0.5f, 1.0f, 0.0f, 0.0f, 1.f, // Vertex 1: Red
        0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 1.f, // Vertex 2: Green
        -0.25f, -0.5f, 0.0f, 0.f, 1.0f, 1.f // Vertex 3: Blue
    };

    // size is actually sizeof(float)*vertices.length
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // elemets buffer object allows to use the same vertex multiple times
    GLuint elements[] = {
        0, 1, 2, 3
    };
    GLuint ebo;
    glGenBuffers(1, &ebo);
    std::cout << "Created elements with id " << ebo << "\n";
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);

    // create shaders
    GLint status; // for error checking
    char buffer[512];
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vxShaderSrc, NULL);
    glCompileShader(vertexShader);
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
    if (status != GL_TRUE) {
        glGetShaderInfoLog(vertexShader, 512, NULL, buffer);
        std::cerr<<"Error in shader: "<<buffer<<"\n";
    }

    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragShaderSrc, NULL);
    glCompileShader(fragmentShader);
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &status);
    if (status != GL_TRUE) {
        glGetShaderInfoLog(fragmentShader, 512, NULL, buffer);
        std::cerr<<"Error in shader: "<<buffer<<"\n";
    }

    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);

    // bind the output
    // this is the actual output by default
    glBindFragDataLocation(shaderProgram, 0, "outColor");

    glLinkProgram(shaderProgram); // called everytime somethign change for the shader
    glUseProgram(shaderProgram);

    GLint posAttrib = glGetAttribLocation(shaderProgram, "position");
    glEnableVertexAttribArray(posAttrib);
    glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, 6*sizeof(GLfloat), 0);
    GLint colAttrib = glGetAttribLocation(shaderProgram, "color");
    glEnableVertexAttribArray(colAttrib);
    glVertexAttribPointer(colAttrib, 4, GL_FLOAT, GL_FALSE,
                          6*sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));

    GLint uniPos = glGetUniformLocation(shaderProgram, "offset");

    while(!glfwWindowShouldClose(window))
    {
        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
            glfwSetWindowShouldClose(window, GL_TRUE);

        glPolygonMode( GL_FRONT_AND_BACK, wire?GL_LINE:GL_FILL );

        float time =  (float)glfwGetTime();

        // Clear the screen to black
        glClearColor(bgColor[0], bgColor[1], bgColor[2], 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glUniform2f(uniPos, cos(time*4.f)*0.5f, sin(time*4.f)*0.5f);
        glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_INT, 0); // we can share vertex and we specify indexes

        glUniform2f(uniPos, 0.f, 0.f);
        // Draw tweak bars
        //glUseProgram(0);
        glBindVertexArray(0);
        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
        TwDraw();
        glUseProgram(shaderProgram);
        glBindVertexArray(vao);
        //glBindBuffer(GL_ARRAY_BUFFER, vbo);
        //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // clean up
    glDeleteProgram(shaderProgram);
    glDeleteShader(fragmentShader);
    glDeleteShader(vertexShader);

    glDeleteBuffers(1, &ebo);
    glDeleteBuffers(1, &vbo);

    glDeleteVertexArrays(1, &vao);

    TwTerminate();
    glfwTerminate();

    return 0;
}

You can compile the code with

g++ src/main.cpp -std=c++11 -DGLEW_STATIC -lGLEW -lglfw3 -framework OpenGL -lAntTweakBar

or

mingw32-g++.exe main.cpp -std=c++11 -DGLEW_STATIC -lglew32 -lglfw3 -lglu32 -lopengl32 -lgdi32 -lAntTweakBar

Adapt if necessary

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1 answer

I found a solution: since I am using CORE:

glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_TRUE);

I need to change this TwInit(TW_OPENGL, NULL);to TwInit(TW_OPENGL_CORE, NULL); I had to fix the AntTweakBar homebrew version to make this work

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Source: https://habr.com/ru/post/1541807/

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