package com.starhack;

import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL14;
import org.lwjgl.opengl.GLContext;

import static org.lwjgl.opengl.EXTFramebufferObject.GL_COLOR_ATTACHMENT0_EXT;
import static org.lwjgl.opengl.EXTFramebufferObject.GL_DEPTH_ATTACHMENT_EXT;
import static org.lwjgl.opengl.EXTFramebufferObject.GL_FRAMEBUFFER_EXT;
import static org.lwjgl.opengl.EXTFramebufferObject.GL_RENDERBUFFER_EXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glBindFramebufferEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glBindRenderbufferEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glFramebufferRenderbufferEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glFramebufferTexture2DEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glGenFramebuffersEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glGenRenderbuffersEXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glRenderbufferStorageEXT;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.util.glu.GLU.*;
import java.io.File;

public class Main {

	private static boolean gameRunning = true;
	private static int fps;
	private static int colorTextureID;
	private static int framebufferID;
	private static int depthRenderBufferID;

	static {
		System.setProperty("org.lwjgl.librarypath",
				new File(new File(System.getProperty("user.dir"), "native"),
						LWJGLUtil.getPlatformName()).getAbsolutePath());
	}

	public static void main(String[] args) {
		try {
			Display.setDisplayMode(new DisplayMode(640, 400));
			Display.setTitle("Starhack");
			Display.setVSyncEnabled(true);
			Display.create();
		} catch (LWJGLException ex) {
			Display.destroy();
			System.exit(1);
		}

		if (!GLContext.getCapabilities().OpenGL11) {
			System.err
			.println("Your OpenGL version doesn't support the required functionality.");
			Display.destroy();
			System.exit(1);
		}

		// check if GL_EXT_framebuffer_object can be use on this system
		if (!GLContext.getCapabilities().GL_EXT_framebuffer_object) {
			System.out.println("Your OpenGL version doesn't support the required functionality.");
			System.exit(0);
		} else {
			framebufferID = glGenFramebuffersEXT();
			colorTextureID = glGenTextures();
			depthRenderBufferID = glGenRenderbuffersEXT();
			glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID);
			glBindTexture(GL_TEXTURE_2D, colorTextureID);
			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, Display.getWidth() / 2, Display.getHeight() / 2, 0, GL_RGBA,
					GL_INT, (java.nio.ByteBuffer) null);
			glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
					GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, colorTextureID, 0);
			glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthRenderBufferID);
			glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,
					GL14.GL_DEPTH_COMPONENT24, Display.getWidth() / 2, Display.getHeight() / 2);
			glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
					GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT,
					depthRenderBufferID);
			glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
		}

		long lastLoopTime = System.nanoTime();
		final int TARGET_FPS = 60;
		final long OPTIMAL_TIME = 1000000000 / TARGET_FPS;

		while (gameRunning) {
			long now = System.nanoTime();
			long updateLength = now - lastLoopTime;
			lastLoopTime = now;
			double delta = updateLength / ((double) OPTIMAL_TIME);

			long lastFpsTime = updateLength;
			fps++;

			if (lastFpsTime >= 1000000000) {
				System.out.println("(FPS: " + fps + ")");
				lastFpsTime = 0;
				fps = 0;
			}
			
			render();

			Display.update();

			try {
				Thread.sleep((lastLoopTime - System.nanoTime() + OPTIMAL_TIME) / 1000000);
			} catch (Exception e) {
			}

			if (Display.isCloseRequested()) {
				gameRunning = false;
			}
		}

		Display.destroy();
		System.exit(0);
	}

	public static void render() {
		render3D();
		render2D();
		glFlush();
	}

	public static void ready3D() {
		glViewport(0, 0, Display.getWidth(), Display.getHeight());
		glMatrixMode(GL_PROJECTION);

		glLoadIdentity();
		gluPerspective(45, (float) Display.getWidth() / Display.getHeight(),
				0.1f, 5000.0f);

		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();

		glDepthFunc(GL_LEQUAL);
		glEnable(GL_DEPTH_TEST);
	}

	public static void ready2D() {
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();

		gluOrtho2D(0.0f, Display.getWidth(), Display.getHeight(), 0.0f);

		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		glTranslatef(0.375f, 0.375f, 0.0f);

		glDisable(GL_DEPTH_TEST);
	}

	public static void render3D() {
		ready3D();

		glViewport (0, 0, Display.getWidth() / 2, Display.getHeight() / 2);

		glBindTexture(GL_TEXTURE_2D, 0);
		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID);

		glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
		glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glColor3f(1,1,1);

		glTranslatef(0f, 0f, -5f);
		glRotatef(30f, 1f, 1f, 1f);

		Cube.wireCube(1);
	}

	public static void render2D() {
		ready2D();
		
		glViewport (0, 0, Display.getWidth(), Display.getHeight());

		glEnable(GL_TEXTURE_2D);
		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

		glClearColor (0.0f, 1.0f, 1.0f, 1.0f);
		glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glBindTexture(GL_TEXTURE_2D, colorTextureID);
		
		glBegin(GL_QUADS);
		glTexCoord2f(0.0f, 0.0f); glVertex2f(0, Display.getHeight());
		glTexCoord2f(1.0f, 0.0f); glVertex2f(Display.getWidth(), Display.getHeight());
		glTexCoord2f(1.0f, 1.0f); glVertex2f(Display.getWidth(), 0);
		glTexCoord2f(0.0f, 1.0f); glVertex2f(0, 0);
		glEnd();
		
		glDisable(GL_TEXTURE_2D);
	}
}