///////////////////////////////////////////////////////////////////////////////
//            Copyright (C) 2004-2007 by The Allacrost Project
//                         All Rights Reserved
//
// This code is licensed under the GNU GPL version 2. It is free software 
// and you may modify it and/or redistribute it under the terms of this license.
// See http://www.gnu.org/copyleft/gpl.html for details.
///////////////////////////////////////////////////////////////////////////////

/** ****************************************************************************
*** \file    screen_rect.h
*** \author  Raj Sharma, roos@allacrost.org
*** \brief   Header file for the ScreenRect class.
*** The ScreenRect class is used for storing rectangles with pixel coordinates
*** ***************************************************************************/

#ifndef __SCREEN_RECT_HEADER__
#define __SCREEN_RECT_HEADER__

#include "defs.h"
#include "utils.h"

namespace hoa_video {

/** ****************************************************************************
*** \brief A structure used for storing rectangles with pixel coordinates
*** This class is used in storing the current scissoring rectangles, viewport
*** rectangles, etc. It is based on standard screen coordinates, where (0,0)
*** is the top-left and the unit is 1 pixel (hence int32 coordinates instead of
*** floats)
*** ***************************************************************************/
class ScreenRect {
public:	
	ScreenRect()
		{}
	ScreenRect(int32 l, int32 t, int32 w, int32 h)
		: left(l), top(t), width(w), height(h) {}

	/** \brief Modifies the rectangle coordinates to be an intersection of itself with another rectangle
	*** \param rect The rectangle to intersect this rectangle with
	*** The resulting intersection rectangle will have all its members set to zero if the two rectangles
	*** do not intersect. If the current rectangle has 100% intersection with the argument rectangle, no
	*** change in coordinates will occur. Typically, the intersection will be a smaller rectangle than
	*** the original two rectangles.
	*** \note This function is defined in video.cpp
	**/
	void Intersect(const ScreenRect &rect)
	{
		// Find max left and top coordinates
		if (rect.left > left)
			left = rect.left;
		if (rect.top > top)
			top = rect.top;

		// Find min right and bottom coordinates
		int32 right = left + width - 1;
		int32 bottom = top + height - 1;
		if (rect.left + rect.width - 1 < right)
			right = rect.left + rect.width - 1;
		if (rect.top + rect.height - 1 < bottom)
			bottom = rect.top + rect.height - 1;

		if (left > right || top > bottom) {
			left = right = width = height = 0;
		}
		else {
			width = right - left + 1;
			height = bottom - top + 1;
		}
	}

	//! \brief Coordinates for the top left corner of the rectangle
	int32 left, top;

	//! \brief Stores the dimensions for this rectangle
	int32 width, height;
}; // class ScreenRect

}  // namespace hoa_video

#endif // __SCREEN_RECT_HEADER__