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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 dummy_land.cpp Handling of void (or dummy) tiles. */

#include "stdafx.h"
#include "tile_cmd.h"
#include "command_func.h"
#include "viewport_func.h"

#include "table/strings.h"
#include "table/sprites.h"

static void DrawTile_Dummy(TileInfo *ti)
{
	DrawGroundSpriteAt(SPR_SHADOW_CELL, PAL_NONE, ti->x, ti->y, ti->z);
}


static uint GetSlopeZ_Dummy(TileIndex tile, uint x, uint y)
{
	return TilePixelHeight(tile);
}

static Foundation GetFoundation_Dummy(TileIndex tile, Slope tileh)
{
	return FOUNDATION_NONE;
}

static CommandCost ClearTile_Dummy(TileIndex tile, DoCommandFlag flags)
{
	return_cmd_error(STR_ERROR_OFF_EDGE_OF_MAP);
}


static void GetTileDesc_Dummy(TileIndex tile, TileDesc *td)
{
	td->str = STR_EMPTY;
	td->owner[0] = OWNER_NONE;
}

static void TileLoop_Dummy(TileIndex tile)
{
	/* not used */
}

static void ChangeTileOwner_Dummy(TileIndex tile, Owner old_owner, Owner new_owner)
{
	/* not used */
}

static TrackStatus GetTileTrackStatus_Dummy(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
{
	return 0;
}

static CommandCost TerraformTile_Dummy(TileIndex tile, DoCommandFlag flags, uint z_new, Slope tileh_new)
{
	return_cmd_error(STR_ERROR_OFF_EDGE_OF_MAP);
}

extern const TileTypeProcs _tile_type_dummy_procs = {
	DrawTile_Dummy,           // draw_tile_proc
	GetSlopeZ_Dummy,          // get_slope_z_proc
	ClearTile_Dummy,          // clear_tile_proc
	NULL,                     // add_accepted_cargo_proc
	GetTileDesc_Dummy,        // get_tile_desc_proc
	GetTileTrackStatus_Dummy, // get_tile_track_status_proc
	NULL,                     // click_tile_proc
	NULL,                     // animate_tile_proc
	TileLoop_Dummy,           // tile_loop_clear
	ChangeTileOwner_Dummy,    // change_tile_owner_clear
	NULL,                     // add_produced_cargo_proc
	NULL,                     // vehicle_enter_tile_proc
	GetFoundation_Dummy,      // get_foundation_proc
	TerraformTile_Dummy,      // terraform_tile_proc
};