package p5.test;

import java.applet.Applet;
import java.awt.Frame;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;

import javax.media.opengl.GL;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLContext;
import javax.media.opengl.GLProfile;

import javax.media.opengl.*;
import javax.media.opengl.awt.GLCanvas;

public class MiniApplet extends Applet {
  private static final long serialVersionUID = 1L;

  private Frame frame;
  private GLProfile profile;
  private GLCapabilities capabilities;
  private GLCanvas canvas;
  private GLContext context0;
  private GLContext context;

  private double theta = 0;
  private double s = 0;
  private double c = 0;

  void setup() {
    // Need to create this canvas first to have rendering working
    canvas = new GLCanvas(null);

    GraphicsEnvironment environment =
      GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice displayDevice = environment.getDefaultScreenDevice();

    frame = new Frame(displayDevice.getDefaultConfiguration());
    frame.setSize(640, 480);
    frame.setVisible(true);

    profile = GLProfile.getMaxFixedFunc();
    capabilities = new GLCapabilities(profile);
    capabilities.setSampleBuffers(false);

    canvas = new GLCanvas(capabilities);
    frame.add(this);
    frame.add(canvas);
    canvas.addGLEventListener(new Renderer());
  }

  void drawLoop() {
    Thread loop = new Thread() {
      public void run() {
        while (true) {
          canvas.display();
        }
      }
    };
    loop.start();
  }

  void draw(GL2 gl) {
    gl.glClearColor(0, 0, 0, 1);
    gl.glClear(GL.GL_COLOR_BUFFER_BIT);

    theta += 0.01;
    s = Math.sin(theta);
    c = Math.cos(theta);

    gl.glBegin(GL.GL_TRIANGLES);
    gl.glColor3f(1, 0, 0);
    gl.glVertex2d(-c, -c);
    gl.glColor3f(0, 1, 0);
    gl.glVertex2d(0, c);
    gl.glColor3f(0, 0, 1);
    gl.glVertex2d(s, -s);
    gl.glEnd();
  }

  class Renderer implements GLEventListener {
    @Override
    public void display(GLAutoDrawable drawable) {
      draw(drawable.getGL().getGL2());

      context = drawable.getContext();
      if (context0 != null && context != null && context.hashCode() != context0.hashCode()) {
        System.out.println("Context changed");
      }
      context0 = context;
    }

    @Override
    public void dispose(GLAutoDrawable drawable) {
    }

    @Override
    public void init(GLAutoDrawable drawable) {
    }

    @Override
    public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) {
    }
  }

  public static void main(String[] args) {
    MiniApplet mini;
    try {
      Class<?> c = Thread.currentThread().getContextClassLoader().loadClass(MiniApplet.class.getName());
      mini = (MiniApplet) c.newInstance();
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
    if (mini != null) {
      mini.setup();
      mini.drawLoop();
    }
  }
}