Triangle not rendering in GLFW3 - c

Question

I recently downloaded GLFW3 since it's better than GLUT from what I heard. I managed to get a window to display and change the clear colors but I cannot figure out why I'm not rendering anything in my draw calls. In this case, it's a triangle. I'm running this on XCode 9.2 and this is the code I have right now:
#define GLFW_INCLUDE_GLCOREARB
#include <stdio.h>
#include <stdlib.h>
#include <GLFW/glfw3.h>
static const GLfloat vertex_buffer_data[] = {
-1.0f, -1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
0.0f, 1.0f, 0.0f,
};
int main(int argc, const char * argv[]) {
GLuint VertexBufferID;
GLFWwindow* window;
/* Initialize the library */
if ( !glfwInit() )
{
return -1;
}
#ifdef __APPLE__
/* We need to explicitly ask for a 3.2 context on OS X */
glfwWindowHint (GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint (GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint (GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
glfwWindowHint (GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#endif
/* Create a windowed mode window and its OpenGL context */
window = glfwCreateWindow( 400 , 400, "Hello World", NULL, NULL );
if (!window)
{
glfwTerminate();
return -1;
}
/* Make the window's context current */
glfwMakeContextCurrent(window);
glGenBuffers(1, &VertexBufferID);
glBindBuffer(GL_ARRAY_BUFFER, VertexBufferID);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer_data), vertex_buffer_data, GL_STATIC_DRAW);
//Edit in
**program = initShaders(VSHADER_SOURCE, FSHADER_SOURCE);**
while (!glfwWindowShouldClose(window))
{
/* Render here */
//set clear color
glClearColor(0.0, 0.0, 0.0, 1.0);
//clear window
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the buffers
//Draw
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, VertexBufferID);
//got error 0x502 on line below
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
//Edit in
**glUseProgram(program);**
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(0);
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
}
glfwTerminate();
return 0;
}
It's probably a minor mistake but I can't see it.
Edit: Okay shaders are required here from what I'm told. I don't know how I got away with it in GLUT. I guess it was an older version. So here are the shader programs I'm using.
"#version 330 core\n"
"layout(location = 0) in vec3 vertexPosition_modelspace;\n"
"void main()\n"
"{\n"
" gl_Position.xyz = vertexPosition_modelspace;\n"
" gl_Position.w = 1.0;\n"
"}\n";
"#version 330 core\n"
"out vec3 color;\n"
"void main()\n"
"{\n"
" color = vec3(1, 0, 0);\n"
"}\n";
I should also mention that I've been following this tutorial for help as well. http://www.opengl-tutorial.org/beginners-tutorials/tutorial-2-the-first-triangle/
As for errors, I found an error in glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0); as code 502, where it apparently means GL_INVALID_OPERATION, which I don't know what that means in this case.

Answer 1

The 2nd parameter of glBufferData is the target type of the buffer and not the named buffer object itself. glBufferData uses the named buffer object which is bound to the specified target:
glBufferData(
GL_ARRAY_BUFFER, // GL_ARRAY_BUFFER instead of VertexBufferID
sizeof(vertex_buffer_data),
vertex_buffer_data,
GL_STATIC_DRAW);
If you want to use a OpenGL Core profile context, then you have to use a shader program, this is not optional.
Further you have to create a named Vertex Array Object, because the default vertex array object (0) is not present in core profile context.
The modern way of rendering in OpenGL, would be to use a Shader program.
If you don't want to use use a shader program, than you have to use a compatibility context and you have to define the array of vertex data using the deprected way by glVertexPointer and you have to enable the client-side capability for vertex coordinates by glEnableClientState( GL_VERTEX_ARRAY ).
glfwWindowHint (GLFW_OPENGL_PROFILE,
GLFW_OPENGL_COMPAT_PROFILE); // instead of GLFW_OPENGL_CORE_PROFILE
.....
glGenBuffers(1, &VertexBufferID);
glBindBuffer(GL_ARRAY_BUFFER, VertexBufferID);
glBufferData(GL_ARRAY_BUFFER,
sizeof(vertex_buffer_data), vertex_buffer_data, GL_STATIC_DRAW);
.....
glEnableClientState( GL_VERTEX_ARRAY );
glBindBuffer(GL_ARRAY_BUFFER, VertexBufferID);
glVertexPointer(3, GL_FLOAT, 0, (void*)0);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableClientState( GL_VERTEX_ARRAY );