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rubidium

(svn r17776) -Codechange: [SDL] make "update the video card"-process asynchronious. Profiling with gprof etc. hasn't shown us that DrawSurfaceToScreen takes a significant amount of CPU; only using TIC/TOC it became apparant that it was a heavy CPU-cycle user or that it was waiting for something.
The benefit of making this function asynchronious ranges from 2%-25% (real time) during fast forward on dual core/hyperthreading-enabled CPUs; 8bpp improvements are, in my test cases, significantly smaller than 32bpp improvements.
On single core non-hyperthreading-enabled CPUs the extra locking/scheduling costs up to 1% extra realtime in fast forward. You can use -v sdl:no_threads to disable threading and undo this loss.
During normal non-fast-forwarded games the benefit/costs are negligable except when the gameloop takes more than about 90% of the time of a tick.
Note that allegro's performance does not improve with this system, likely due to their way of getting data to the video card. It is not implemented for the OS X/Windows video backends, unless (ofcourse) SDL is used there.
Funny is that the performance of the 32bpp(-anim) blitter is, at least in some test cases, significantly faster (more than 10%) than the 8bpp(-optimized) blitter when looking at real time in fast forward on a dual core CPU; it was slower.
The idea comes from a paper/report by Idar Borlaug and Knut Imar Hagen.

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file map_type.h Types related to maps. */

#ifndef MAP_TYPE_H
#define MAP_TYPE_H

/**
 * Data that is stored per tile. Also used TileExtended for this.
 * Look at docs/landscape.html for the exact meaning of the members.
 */
struct Tile {
	byte   type_height; ///< The type (bits 4..7) and height of the northern corner
	byte   m1;          ///< Primarily used for ownership information
	uint16 m2;          ///< Primarily used for indices to towns, industries and stations
	byte   m3;          ///< General purpose
	byte   m4;          ///< General purpose
	byte   m5;          ///< General purpose
	byte   m6;          ///< Primarily used for bridges and rainforest/desert
};

/**
 * Data that is stored per tile. Also used Tile for this.
 * Look at docs/landscape.html for the exact meaning of the members.
 */
struct TileExtended {
	byte m7; ///< Primarily used for newgrf support
};

/**
 * An offset value between to tiles.
 *
 * This value is used fro the difference between
 * to tiles. It can be added to a tileindex to get
 * the resulting tileindex of the start tile applied
 * with this saved difference.
 *
 * @see TileDiffXY(int, int)
 */
typedef int32 TileIndexDiff;

/**
 * A pair-construct of a TileIndexDiff.
 *
 * This can be used to save the difference between to
 * tiles as a pair of x and y value.
 */
struct TileIndexDiffC {
	int16 x;        ///< The x value of the coordinate
	int16 y;        ///< The y value of the coordinate
};

/** Minimal and maximal map width and height */
enum {
	MIN_MAP_SIZE_BITS = 6,                      ///< Minimal size of map is equal to 2 ^ MIN_MAP_SIZE_BITS
	MAX_MAP_SIZE_BITS = 11,                     ///< Maximal size of map is equal to 2 ^ MAX_MAP_SIZE_BITS
	MIN_MAP_SIZE      = 1 << MIN_MAP_SIZE_BITS, ///< Minimal map size = 64
	MAX_MAP_SIZE      = 1 << MAX_MAP_SIZE_BITS, ///< Maximal map size = 2048
};

/**
 * Approximation of the length of a straight track, relative to a diagonal
 * track (ie the size of a tile side).
 *
 * #defined instead of const so it can
 * stay integer. (no runtime float operations) Is this needed?
 * Watch out! There are _no_ brackets around here, to prevent intermediate
 * rounding! Be careful when using this!
 * This value should be sqrt(2)/2 ~ 0.7071
 */
#define STRAIGHT_TRACK_LENGTH 7071/10000

#endif /* MAP_TYPE_H */