//! GLU Picker
/*!
 * A class to perform picking in a (hopefully) easier manner
 * Instructions:
 *
 * 1) Use glLoadName with a different number when rendering each "pickable" object
 *
 * 2) Use picker's PerformPicking() in ProcessEvent method. The returned object will be the closest
 *
 * 3) If you want you can look at App.currentlyPicking in your Redraw method
 * (e.g. to simplify graphics, not draw ignored objects, etc. when in picking mode)
 *
 *
 * Based in a great tutorial by gpWiki: http://gpwiki.org/index.php/OpenGL:Tutorials:Picking
 *
 */
/*
 * Copyright (C) 2010  Alejandro Valenzuela Roca, <lanjoe9 at mexinetica NOSPAMPLEASE dot com>, http://lj9.mexinetica.com/
 *
 * This file is part of MotorJ, a free framework for videogame development.
 * <http://wiki.lidsol.net/wiki/index.php?title=MotorJ >
 * <http://motorj.mexinetica.com/ >
 *
 * MotorJ is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MotorJ is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with MotorJ.  If not, see <http://www.gnu.org/licenses/>.
 */



#include "picker-class.h"
extern mjApplication App;

mjPicker::mjPicker()
{
	// Init using the default size
	selBuffer = NULL;
	SetBufferSize(MJ_SEL_BUFF_SIZE);
}

mjPicker::mjPicker(GLuint selBufferSize)
{
	selBuffer = NULL;
	SetBufferSize(selBufferSize);

}

void mjPicker::SetBufferSize(GLuint selBufferSize)
{
	bufferSize = selBufferSize;

	if (selBuffer)
		delete selBuffer;

	selBuffer = new GLuint[bufferSize];
	selRadius = 3.0;
	App.currentlyPicking = false;
	glSelectBuffer(bufferSize, selBuffer);
}



int mjPicker::PerformPicking(GLfloat x, GLfloat y)
{
	int i;
	int minZ;
	int selected;
	GLfloat M[16];
	GLint view[4];

	App.currentlyPicking = true;

	glRenderMode(GL_SELECT);
	glInitNames();

	glPushName(99); // Get a default object inside the picking stack
	glGetFloatv(GL_PROJECTION_MATRIX, M);
	glMatrixMode(GL_PROJECTION);
 	glLoadIdentity(); // Load the identity matrix
 	/*
	 restrict the draw to an area around the cursor
	 */
	glGetIntegerv(GL_VIEWPORT, view);
 	gluPickMatrix(x, y, 3.0, 3.0, view);
 	glGetFloatv(GL_PROJECTION_MATRIX, pickingMatrix); // Multiply the picking matrix
	glMultMatrixf(M); // Multiply the projection matrix
 	glMatrixMode(GL_MODELVIEW); // Return to modelview mode
 	App.currentUniverse->Redraw(); // Draw
 	glMatrixMode(GL_PROJECTION); // Return to projection mode
	glLoadMatrixf(M); // Restore the original projection matrix
	selHits = glRenderMode(GL_RENDER); // Get the number of hits
	glMatrixMode(GL_MODELVIEW); // return to modelview mode
	App.currentlyPicking = false;
	//printf("\n\n*************");
	if (selHits > 0)
	{
		for (i = 0; i < selHits; i++)
		{
			if (i == 0)
			{
				minZ = selBuffer[i * 4 + 1];
				selected = selBuffer[i * 4 + 3];
			} else if (selBuffer[i * 4 + 1] < minZ)
			{
				minZ = selBuffer[i * 4 + 1];
				selected = selBuffer[i * 4 + 3];
			}
 			/*printf(	"Number: %d\n"
			 "Min Z: %d\n"
			 "Max Z: %d\n"
			 "Name on stack: %d\n",
			 (GLubyte)selBuffer[i * 4],
			 (GLubyte)selBuffer[i * 4 + 1],
			 (GLubyte)selBuffer[i * 4 + 2],
			 (GLubyte)selBuffer[i * 4 + 3]
			 );*/
 		}


 		//printf("selected: %d\n\n", selected);
 		return selected;
 	}
	return 0;

}
mjPicker::~mjPicker()
{
	printf("Calling destructor\n");
	delete selBuffer;
}