Why isn't OpenGL drawing anything? - c++

Question

This code is supposedly the code to draw a triangle however all I get is a black screen. Why am I not getting anything drawn?
Secondly, in my array of vertices, if I put an 'f' after my coordinates like I always see in tutorials I get an error about an invalid digit in an octal. Why can everyone else use 'f' after their numbers and not me?
I am using openGL 4.1 on OSX Yosemite.
#include <iostream>
//Using SDL and standard IO
#include <SDL2/SDL.h>
//#define GL_GLEXT_PROTOTYPES 1
//#include <SDL2/SDL_opengl.h>
#include <GLUT/glut.h>
#include <stdio.h>
#include <OpenGL/gl3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <string.h>
using namespace std;
//Screen dimension constants
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
bool SetOpenGLAttributes()
{
// Set our OpenGL version.
// SDL_GL_CONTEXT_CORE gives us only the newer version, deprecated functions are disabled
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
return true;
}
int main( int argc, char* args[] )
{
//The window we'll be rendering to
SDL_Window* window = NULL;
//Initialize SDL
if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() );
}
else
{
SetOpenGLAttributes();
//Create window
window = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_OPENGL );
if( window == NULL )
{
printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );
}
else
{
//creating new context
SDL_GL_CreateContext(window);
GLuint vertexArrayID;
glGenVertexArrays(1, &vertexArrayID);
glBindVertexArray(vertexArrayID);
printf("%s", "This is your version");
printf("%s\n", glGetString(GL_VERSION));
printf("%s", glGetString(GL_RENDERER));
SDL_GL_SetSwapInterval(1);
glEnable(GL_DEPTH_TEST);
float r = 0.5;
static const GLfloat cubeV[] = {
-.5, 0, 0,
.5, 0, 0,
0, .5, 0
};
GLuint vertexBuffer;
glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(cubeV), cubeV, GL_STATIC_DRAW);
SDL_GL_SwapWindow(window);
bool running = true;
while(running){
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glVertexAttribPointer(
0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
3, // size
GL_FLOAT, // type
GL_FALSE, // normalized?
0, // stride
(void*)0 // array buffer offset
);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(0);
glFlush();
SDL_GL_SwapWindow(window);
SDL_Delay(17);
}
}
}
//Destroy window
//SDL_DestroyWindow( window );
//Quit SDL subsystems
//SDL_Quit();
return 0;
}