OpenGL triangle not rendering - c++

Question

I've written some OpenGL code in c++ to render a red triangle to the screen. The program uses opengl 3.3 and glsl version 330. I've narrowed down the code that doesn't work to a few .cpp class files or my glsl code. I get no compiler or linker errors (I do get some linker warnings but I dont think those are important). I've given the code in what I believe to be the most likely place for errors to occur.
Renderer.cpp:
#include "Renderer.h"
#include <GL/glew.h>
void Renderer::render(int vbo){
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(0);
}
ShaderProgram.cpp
#pragma warning(disable:4101)
#include "ShaderProgram.h"
#include <fstream>
#include <sstream>
ShaderProgram::ShaderProgram(std::string vertexLocation, std::string fragmentLocation){
programID = glCreateProgram();
vertexID = glCreateShader(GL_VERTEX_SHADER);
fragmentID = glCreateShader(GL_FRAGMENT_SHADER);
createShader(vertexID, vertexLocation);
createShader(fragmentID, fragmentLocation);
glLinkProgram(programID);
GLint success;
glGetProgramiv(programID, GL_LINK_STATUS, &success);
if (success == 0) {
GLchar ErrorLog[1024];
glGetProgramInfoLog(programID, sizeof(ErrorLog), nullptr, ErrorLog);
fprintf(stderr, "Error linking shader program: '%s'\n", ErrorLog);
}
glValidateProgram(programID);
glUseProgram(programID);
}
void ShaderProgram::createShader(GLint shaderID, std::string srcLocation){
const std::string shaderText = loadShaderSource(srcLocation);
const GLchar* shaderSource = shaderText.data();
glShaderSource(shaderID, 1, &shaderSource, nullptr);
glCompileShader(shaderID);
GLint success;
glGetShaderiv(shaderID, GL_COMPILE_STATUS, &success);
if (!success) {
GLchar InfoLog[1024];
glGetShaderInfoLog(shaderID, sizeof(InfoLog), nullptr, InfoLog);
fprintf(stderr, "Error compiling shader: '%s'\n", InfoLog);
}
glAttachShader(programID, shaderID);
}
std::string ShaderProgram::loadShaderSource(std::string location){
std::ifstream file (location);
std::string source;
std::stringstream stringStream;
if (!file.is_open()){
throw std::runtime_error("Could not open file " + location);
}
stringStream << file.rdbuf();
source = stringStream.str();
return source;
}
Entity.cpp
#include "Entity.h"
Entity::Entity(){
vertices[0] = glm::vec3(-1.0f, -1.0f, 0.0f);
vertices[1] = glm::vec3(1.0f, -1.0f, 0.0f);
vertices[2] = glm::vec3(0.0f, 1.0f, 0.0f);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glDisableVertexAttribArray(0);
}
int Entity::getID(){
return vbo;
}
GLSL Code:
Vertex Shader:
#version 330
layout (location = 0) in vec3 position;
void main(){
gl_Position = vec4(0.5 * position.x, 0.5 * position.y, position.z, 1.0);
}
Fragment Shader:
#version 330
out vec4 colour;
void main(){
colour = vec4(1.0, 0.0, 0.0, 1.0);
}

Answer 1

you cant use glm::vec3 like this.Reference to it doesn't provide you anything.Start of its real array obtained :
glm::vec3 k;
float* t= &k[0];
But i doubt you can do something worth with it too.
use just float GLfloat array.