package com.windpoweredgames.mocha.util;

import static org.lwjgl.opengl.GL11.glLoadIdentity;
import static org.lwjgl.opengl.GL11.glMatrixMode;

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

import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL11;
import org.lwjgl.util.glu.GLU;
import org.lwjgl.util.vector.Vector3f;

import com.windpoweredgames.mocha.GameEngine;
import com.windpoweredgames.mocha.display.GameDisplay;

public class UnprojectUtil {


    public static Vector3f unproject(int mouseX, int mouseY){
        Vector3f v1 = unproject(mouseX, mouseY, 0);
        Vector3f v2 = unproject(mouseX, mouseY, 1);
        Vector3f normalized = new Vector3f(v2.x - v1.x, v2.y - v1.y, v2.z - v1.z );
        return normalized;
    }


    public static Vector3f unproject(int mouseX, int mouseY, float depth){
        IntBuffer viewport = BufferUtils.createIntBuffer(16);
        FloatBuffer modelView = BufferUtils.createFloatBuffer(16);
        FloatBuffer projectionView = BufferUtils.createFloatBuffer(16);
        float winX = mouseX;
        float winY = mouseY;
        FloatBuffer position = BufferUtils.createFloatBuffer(3);


            GL11.glGetFloat(GL11.GL_MODELVIEW_MATRIX, modelView);
            GL11.glGetFloat(GL11.GL_PROJECTION_MATRIX, projectionView);
            GL11.glGetInteger(GL11.GL_VIEWPORT, viewport);


            winY = viewport.get(3) - mouseY; // due to inverted coords
            GLU.gluUnProject(winX, winY, depth, modelView, projectionView, viewport, position);
            position.rewind();
            Vector3f result = new Vector3f(position.get(0), -position.get(1), position.get(2));

        return result;
    }


}