package com.starshock;

import java.io.File;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;

import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.Sys;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL30.*;
import static org.lwjgl.util.glu.GLU.*;

public class Main {

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

    public static final int S_WIDTH = 320, S_HEIGHT = 200, S_SCALE = 2;

    public long lastFrame, lastFPS;
    public int fps;
    public int defaultFBO = 0, drawFBO, drawFBOTexture;

    public void start() {
        try {
            Display.setDisplayMode(new DisplayMode(S_WIDTH * S_SCALE, S_HEIGHT
                    * S_SCALE));
            Display.setTitle("Starhack - FPS: " + fps);
            Display.create();
        } catch (LWJGLException e) {
            e.printStackTrace();
            System.exit(0);
        }

        initFBO();

        getDelta();
        lastFPS = getTime();

        while (!Display.isCloseRequested()) {
            int delta = getDelta();

            update(delta);
            renderGL();

            Display.update();
            Display.sync(60);
        }

        Display.destroy();
    }

    public void update(int delta) {
        updateFPS();
    }

    public int getDelta() {
        long time = getTime();
        int delta = (int) (time - lastFrame);
        lastFrame = time;

        return delta;
    }

    public long getTime() {
        return (Sys.getTime() * 1000) / Sys.getTimerResolution();
    }

    public void updateFPS() {
        if (getTime() - lastFPS > 1000) {
            Display.setTitle("Starhack - FPS: " + fps);
            fps = 0;
            lastFPS += 1000;
        }
        fps++;
    }

    public void initFBO() {
        IntBuffer buffer = ByteBuffer.allocateDirect(4)
                .order(ByteOrder.nativeOrder()).asIntBuffer();
        glGenFramebuffers(buffer);
        drawFBO = buffer.get();
        buffer = ByteBuffer.allocateDirect(4).order(ByteOrder.nativeOrder())
                .asIntBuffer();
        glGenTextures(buffer);
        drawFBOTexture = buffer.get();
        glBindFramebuffer(GL_FRAMEBUFFER, drawFBO);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                GL_TEXTURE_2D, drawFBOTexture, 0);
    }

    public void renderGL() {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glBindFramebuffer(GL_FRAMEBUFFER, drawFBO);
        ready3D();
        render3D();
        ready2D();
        render2D();
        renderScaledFBO();
    }

    public void ready3D() {
        glViewport(0, 0, S_WIDTH, S_HEIGHT);
        glMatrixMode(GL_PROJECTION);

        glLoadIdentity();
        gluPerspective(45f, (float) S_WIDTH / S_HEIGHT, 0.0f, 5000.0f);

        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glDepthFunc(GL_LEQUAL);
        glEnable(GL_DEPTH_TEST);
    }

    public void render3D() {
        glTranslatef(0, 0, -6f);
        glBegin(GL_QUADS);
        glVertex3f(0, 0, 0);
        glVertex3f(2, 0, 0);
        glVertex3f(2, 2, 0);
        glVertex3f(0, 2, 0);
        glEnd();
    }

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

        gluOrtho2D(0.0f, S_WIDTH, S_HEIGHT, 0.0f);

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

        glDisable(GL_DEPTH_TEST);
    }

    public void render2D() {
    }

    public void renderScaledFBO() {
        glViewport(0, 0, S_WIDTH * S_SCALE, S_HEIGHT * S_SCALE);
        glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
        glBlitFramebuffer(0, 0, S_WIDTH, S_HEIGHT, 0, 0, S_WIDTH * S_SCALE,
                S_HEIGHT * S_SCALE, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    }

    public static void main(String[] argv) {
        Main main = new Main();
        main.start();
    }
}