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);
    }
}