JOGL (GL3) not rendering a single thing

Newbie & Debugging Questions
#1

I’ve spent whole day trying to make this render my triangle. Didn’t happen. What am I doing wrong ? Syntax is OK. Screen gets filled with background color of Z-Buffer and no triangle appears. I’ve been used to old glBegin(), glEnd() style and I have almost no idea what am I doing now.

What I understand:

  1. How buffers work,
  2. How to reference buffers with IntBuffer
  3. How to feed them with data using glBufferData.
  4. Binding buffers.

What I do not understand:

  1. What gl.glEnableVertexAttribArray(0); does ?
  2. How do I change color of those vertices ? Are they drawn the same color as background, so they’re invisible ?

package opengltest;

import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import javax.media.opengl.GL2;
import javax.media.opengl.GL3;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;

import jogamp.graph.font.typecast.ot.table.Program;

public class SceneRenderer implements GLEventListener {

	private GLU glu = new GLU();

	private float triangle[] = { 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f,
			1.0f, 0.0f };
	private FloatBuffer verticesBuffer = FloatBuffer.wrap(triangle);
	private IntBuffer vbos = IntBuffer.allocate(1);

	@Override
	public void init(GLAutoDrawable drawable) {
		GL3 gl = drawable.getGL().getGL3();

		gl.glEnable(GL3.GL_DEPTH_TEST);
		gl.glDepthFunc(GL3.GL_LEQUAL);
		gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

		gl.glGenBuffers(1, vbos);


		gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vbos.get(0));

		gl.glBufferData(GL3.GL_ARRAY_BUFFER, 9 * 4, verticesBuffer,
				GL3.GL_STATIC_DRAW);

		gl.glFinish();
		
	}

	@Override
	public void dispose(GLAutoDrawable drawable) {

	}

	@Override
	public void display(GLAutoDrawable drawable) {

		GL3 gl = drawable.getGL().getGL3();
		gl.glClear(GL3.GL_DEPTH_BUFFER_BIT | GL3.GL_COLOR_BUFFER_BIT);

		gl.glEnableVertexAttribArray(0);
		gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vbos.get(0));
		gl.glVertexAttribPointer(0, 3, GL3.GL_FLOAT, true, 0, 0);

		gl.glDrawArrays(GL3.GL_TRIANGLES, 0, 3);
		gl.glDisableVertexAttribArray(0);
		gl.glFinish();
		gl.glFlush();

	}

	@Override
	public void reshape(GLAutoDrawable drawable, int x, int y, int width,
			int height) {
		float aspect = (float) width / (float) height;
		glu.gluPerspective(85.0f, aspect, 0.1f, 100.0f);
		drawable.getGL().glViewport(0, 0, width, height);
		

	}

}