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68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*/
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#include "common/util.h"
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namespace Graphics {
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void drawLine(int x0, int y0, int x1, int y1, int color, void (*plotProc)(int, int, int, void *), void *data) {
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// Bresenham's line algorithm, as described by Wikipedia
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const bool steep = ABS(y1 - y0) > ABS(x1 - x0);
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if (steep) {
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SWAP(x0, y0);
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SWAP(x1, y1);
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}
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const int delta_x = ABS(x1 - x0);
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const int delta_y = ABS(y1 - y0);
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const int delta_err = delta_y;
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int x = x0;
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int y = y0;
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int err = 0;
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const int x_step = (x0 < x1) ? 1 : -1;
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const int y_step = (y0 < y1) ? 1 : -1;
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if (steep)
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(*plotProc)(y, x, color, data);
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else
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(*plotProc)(x, y, color, data);
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while (x != x1) {
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x += x_step;
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err += delta_err;
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if (2 * err > delta_x) {
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y += y_step;
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err -= delta_x;
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}
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if (steep)
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(*plotProc)(y, x, color, data);
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else
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(*plotProc)(x, y, color, data);
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}
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}
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} // End of namespace Graphics
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