cpp/openttd-patchpack/source Files · src/saveload/animated_tile_sl.cpp

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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 animated_tile_sl.cpp Code handling saving and loading of animated tiles */

#include "../stdafx.h"
#include "../tile_type.h"
#include "../core/alloc_func.hpp"

#include "saveload.h"

extern TileIndex *_animated_tile_list;
extern uint _animated_tile_count;
extern uint _animated_tile_allocated;

/**
 * Save the ANIT chunk.
 */
static void Save_ANIT()
{
	SlSetLength(_animated_tile_count * sizeof(*_animated_tile_list));
	SlArray(_animated_tile_list, _animated_tile_count, SLE_UINT32);
}

/**
 * Load the ANIT chunk; the chunk containing the animated tiles.
 */
static void Load_ANIT()
{
	/* Before version 80 we did NOT have a variable length animated tile table */
	if (CheckSavegameVersion(80)) {
		/* In pre version 6, we has 16bit per tile, now we have 32bit per tile, convert it ;) */
		SlArray(_animated_tile_list, 256, CheckSavegameVersion(6) ? (SLE_FILE_U16 | SLE_VAR_U32) : SLE_UINT32);

		for (_animated_tile_count = 0; _animated_tile_count < 256; _animated_tile_count++) {
			if (_animated_tile_list[_animated_tile_count] == 0) break;
		}
		return;
	}

	_animated_tile_count = (uint)SlGetFieldLength() / sizeof(*_animated_tile_list);

	/* Determine a nice rounded size for the amount of allocated tiles */
	_animated_tile_allocated = 256;
	while (_animated_tile_allocated < _animated_tile_count) _animated_tile_allocated *= 2;

	_animated_tile_list = ReallocT<TileIndex>(_animated_tile_list, _animated_tile_allocated);
	SlArray(_animated_tile_list, _animated_tile_count, SLE_UINT32);
}

/**
 * "Definition" imported by the saveload code to be able to load and save
 * the animated tile table.
 */
extern const ChunkHandler _animated_tile_chunk_handlers[] = {
	{ 'ANIT', Save_ANIT, Load_ANIT, NULL, CH_RIFF | CH_LAST},
};