cpp/openttd-patchpack/source Files · tile.c

Files @ r3016:b28a60dfd364

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Location: cpp/openttd-patchpack/source/tile.c

r3016:b28a60dfd364 1.0 KiB text/x-c Show Annotation Show as Raw Download as Raw

bjarni

(svn r3596) -Codechange: [OSX] changed to use Apple's macros instead of OTTD macros for endian conversion
This increases the execution speed a lot since GCC can't detect the OTTD macro as an endian conversion
while Apple's code uses the instruction to convert endian instead of a series of instructions to produce the same result

Since we don't have that many endian conversions in the game, overall performance should not increase noteworthy

/* $Id$ */

#include "stdafx.h"
#include "tile.h"

void SetMapExtraBits(TileIndex tile, byte bits)
{
	assert(tile < MapSize());
	SB(_m[tile].extra, 0, 2, bits & 3);
}

uint GetMapExtraBits(TileIndex tile)
{
	assert(tile < MapSize());
	return GB(_m[tile].extra, 0, 2);
}


uint GetTileSlope(TileIndex tile, uint *h)
{
	uint a;
	uint b;
	uint c;
	uint d;
	uint min;
	uint r;

	assert(tile < MapSize());

	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) {
		if (h != NULL) *h = 0;
		return 0;
	}

	min = a = TileHeight(tile);
	b = TileHeight(tile + TileDiffXY(1, 0));
	if (min >= b) min = b;
	c = TileHeight(tile + TileDiffXY(0, 1));
	if (min >= c) min = c;
	d = TileHeight(tile + TileDiffXY(1, 1));
	if (min >= d) min = d;

	r = 0;
	if ((a -= min) != 0) r += (--a << 4) + 8;
	if ((c -= min) != 0) r += (--c << 4) + 4;
	if ((d -= min) != 0) r += (--d << 4) + 2;
	if ((b -= min) != 0) r += (--b << 4) + 1;

	if (h != NULL)
		*h = min * 8;

	return r;
}

uint GetTileZ(TileIndex tile)
{
	uint h;
	GetTileSlope(tile, &h);
	return h;
}