CODEWITHSUNDEEP
c++macosopenglglfw
James Heath
James Heath

Reputation: 46

OpenGL not drawing on Mavericks with GLFW and GLLoadGen

I'm attempting to setup a cross-platform codebase for OpenGL work, and the following code draws just fine on the Windows 7 partition of my hard drive. However, on Mavericks I only get a black screen and can't figure out why. I've tried all the things suggested in the guides and in related questions on here but nothing has worked so far! Hopefully I'm just missing something obvious, as I'm still quite new to OpenGL.

#include "stdafx.h"

#include "gl_core_4_3.hpp"
#include <GLFW/glfw3.h>

int main(int argc, char* argv[])
{
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, 1);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);

    if (!glfwInit())
    {
        fprintf(stderr, "ERROR");
        glfwTerminate();
        return 1;
    }

    GLFWwindow* window = glfwCreateWindow(640, 480, "First GLSL Triangle", nullptr, nullptr);
    if (!window)
    {
        fprintf(stderr, "ERROR");
        glfwTerminate();
        return 1;
    }

    glfwMakeContextCurrent(window);

    gl::exts::LoadTest didLoad = gl::sys::LoadFunctions();
    if (!didLoad)
    {
        fprintf(stderr, "ERROR");
        glfwTerminate();
        return 1;
    }

    printf("Number of functions that failed to load: %i\n", didLoad.GetNumMissing()); // This is returning 16 on Windows and 82 on Mavericks, however i have no idea how to fix that.

    gl::Enable(gl::DEPTH_TEST);
    gl::DepthFunc(gl::LESS);

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

    GLuint vbo = 0;
    gl::GenBuffers(1, &vbo);
    gl::BindBuffer(gl::ARRAY_BUFFER, vbo);
    gl::BufferData(gl::ARRAY_BUFFER, sizeof(points) * sizeof(points[0]), points, gl::STATIC_DRAW);

    GLuint vao = 0;
    gl::GenVertexArrays(1, &vao);
    gl::BindVertexArray(vao);
    gl::EnableVertexAttribArray(0);
    gl::BindBuffer(gl::ARRAY_BUFFER, vbo);
    gl::VertexAttribPointer(0, 3, gl::FLOAT, 0, 0, NULL);

    const char* vertexShader = 
        "#version 400\n"
        "in vec3 vp;"
        "void main() {"
        "   gl_Position = vec4(vp, 1.0);"
        "}";

    const char* fragmentShader =
        "#version 400\n"
        "out vec4 frag_colour;"
        "void main() {"
        "   frag_colour = vec4(1.0, 1, 1, 1.0);"
        "}";

    GLuint vs = gl::CreateShader(gl::VERTEX_SHADER);
    gl::ShaderSource(vs, 1, &vertexShader, nullptr);
    gl::CompileShader(vs);

    GLuint fs = gl::CreateShader(gl::FRAGMENT_SHADER);
    gl::ShaderSource(fs, 1, &fragmentShader, nullptr);
    gl::CompileShader(fs);

    GLuint shaderProgram = gl::CreateProgram();
    gl::AttachShader(shaderProgram, fs);
    gl::AttachShader(shaderProgram, vs);
    gl::LinkProgram(shaderProgram);

    while (!glfwWindowShouldClose(window))
    {
        gl::ClearColor(0, 0, 0, 0);
        gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT);
        gl::UseProgram(shaderProgram);
        gl::BindVertexArray(vao);

        gl::DrawArrays(gl::TRIANGLES, 0, 3);

        glfwPollEvents();
        glfwSwapBuffers(window);
    }

    glfwTerminate();
    return 0;
}

Compiling through Xcode, using a 2013 Macbook Mini, Intel HD Graphics 5000. It's also probably worth noting that the GLLoadGen GetNumMissing() method is returning 82 missing functions on OSX, and I have no idea why that is or how to fix it. GLFW is including gl.h as opposed to gl3.h, but forcing it to include gl3.h by declaring the required macro outputs a warning about including both headers and still nothing draws. Any help or suggestions would be great.

Upvotes: 0

Views: 401

Answers (2)

datenwolf
datenwolf

Reputation: 162307

You have to call glfwInit before you call any other GLFW function. Also register an error callback so that get diagnostics why a certain GLFW operation failed. You requested a OpenGL profile not supported by MacOS X Mavericks. But calling glfwInit after setting the window hints resets that selection, hence why you get a window+context, but not the desired profile. Pulling glfwInit in front solves that problem, but now your window+context creation fails due to lack of OS support.

Upvotes: 2

doron
doron

Reputation: 28932

After every openGL call, check to see that there is no error (use glGetError or gl::GetError. With your shaders, you must check to see that they have compiled properly, there may well be errors.So check that as well (glGetShader and glShaderInfoLog). Do the same for the link stage.

Upvotes: 0

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