mkxp/src/tileatlas.cpp

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2013-10-09 11:44:15 +00:00
/*
** tileatlas.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2013 Jonas Kulla <Nyocurio@gmail.com>
**
** mkxp 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, either version 2 of the License, or
** (at your option) any later version.
**
** mkxp 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 mkxp. If not, see <http://www.gnu.org/licenses/>.
*/
#include "tileatlas.h"
namespace TileAtlas
{
/* A Column represents a Rect
* with undefined width */
struct Column
{
int x, y, h;
Column(int x, int y, int h)
: x(x), y(y), h(h)
{}
};
typedef std::vector<Column> ColumnVec;
/* Autotile area width */
static const int atAreaW = 96*4;
/* Autotile area height */
static const int atAreaH = 128*7;
/* Autotile area */
static const int atArea = atAreaW * atAreaH;
static const int tilesetW = 256;
static const int tsLaneW = tilesetW / 2;
static int freeArea(int width, int height)
{
return width * height - atArea;
}
Vec2i minSize(int tilesetH, int maxAtlasSize)
{
int width = atAreaW;
int height = atAreaH;
const int tsArea = tilesetW * tilesetH;
/* Expand vertically */
while (freeArea(width, height) < tsArea && height < maxAtlasSize)
height += 32;
if (freeArea(width, height) >= tsArea && height <= maxAtlasSize)
return Vec2i(width, height);
/* Expand horizontally */
while (freeArea(width, height) < tsArea && width < maxAtlasSize)
width += tsLaneW;
if (freeArea(width, height) >= tsArea && width <= maxAtlasSize)
return Vec2i(width, height);
return Vec2i(-1, -1);
}
static ColumnVec calcSrcCols(int tilesetH)
{
ColumnVec cols;
cols.reserve(2);
cols.push_back(Column(0, 0, tilesetH));
cols.push_back(Column(tsLaneW, 0, tilesetH));
return cols;
}
static ColumnVec calcDstCols(int atlasW, int atlasH)
{
ColumnVec cols;
cols.reserve(3);
/* Columns below the autotile area */
const int underAt = atlasH - atAreaH;
for (int i = 0; i < 3; ++i)
cols.push_back(Column(i*tsLaneW, atAreaH, underAt));
if (atlasW <= atAreaW)
return cols;
const int remCols = (atlasW - atAreaW) / tsLaneW;
for (int i = 0; i < remCols; ++i)
cols.push_back(Column(i*tsLaneW + atAreaW, 0, atlasH));
return cols;
}
static BlitVec calcBlitsInt(ColumnVec &srcCols, ColumnVec &dstCols)
{
BlitVec blits;
/* Using signed indices here is safer, as we
* might decrement dstI while it is zero. */
int dstI = 0;
for (size_t srcI = 0; srcI < srcCols.size(); ++srcI)
{
Column &srcCol = srcCols[srcI];
for (; dstI < (int) dstCols.size() && srcCol.h > 0; ++dstI)
{
Column &dstCol = dstCols[dstI];
if (srcCol.h > dstCol.h)
{
/* srcCol doesn't fully fit into dstCol */
blits.push_back(Blit(srcCol.x, srcCol.y,
dstCol.x, dstCol.y, dstCol.h));
srcCol.y += dstCol.h;
srcCol.h -= dstCol.h;
}
else if (srcCol.h < dstCol.h)
{
/* srcCol fits into dstCol with space remaining */
blits.push_back(Blit(srcCol.x, srcCol.y,
dstCol.x, dstCol.y, srcCol.h));
dstCol.y += srcCol.h;
dstCol.h -= srcCol.h;
/* Queue this column up again for processing */
--dstI;
srcCol.h = 0;
}
else
{
/* srcCol fits perfectly into dstCol */
blits.push_back(Blit(srcCol.x, srcCol.y,
dstCol.x, dstCol.y, dstCol.h));
}
}
}
return blits;
}
BlitVec calcBlits(int tilesetH, const Vec2i &atlasSize)
{
ColumnVec srcCols = calcSrcCols(tilesetH);
ColumnVec dstCols = calcDstCols(atlasSize.x, atlasSize.y);
return calcBlitsInt(srcCols, dstCols);
}
Vec2i tileToAtlasCoor(int tileX, int tileY, int tilesetH, int atlasH)
{
int laneX = tileX*32;
int laneY = tileY*32;
int longlaneH = atlasH;
int shortlaneH = longlaneH - atAreaH;
int longlaneOffset = shortlaneH * 3;
int laneIdx = 0;
int atlasY = 0;
/* Check if we're inside the 2nd lane */
if (laneX >= tsLaneW)
{
laneY += tilesetH;
laneX -= tsLaneW;
}
if (laneY < longlaneOffset)
{
/* Below autotile area */
laneIdx = laneY / shortlaneH;
atlasY = laneY % shortlaneH + atAreaH;
}
else
{
/* Right of autotile area */
int _y = laneY - longlaneOffset;
laneIdx = 3 + _y / longlaneH;
atlasY = _y % longlaneH;
}
int atlasX = laneIdx * tsLaneW + laneX;
return Vec2i(atlasX, atlasY);
}
}