96 lines
2.2 KiB
C++
96 lines
2.2 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 modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "ultima/nuvie/misc/u6_line_walker.h"
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namespace Ultima {
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namespace Nuvie {
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U6LineWalker::U6LineWalker(uint32 sx, uint32 sy, uint32 ex, uint32 ey)
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: start_x(sx), start_y(sy), end_x(ex), end_y(ey), cur_x(sx), cur_y(sy), cur_step(0) {
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sint32 delta_x = end_x - start_x;
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sint32 delta_y = end_y - start_y;
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yoffset[0] = 0;
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if (delta_x >= 0) {
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xoffset[0] = 1;
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xoffset[1] = 1;
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} else {
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delta_x = -delta_x;
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xoffset[0] = -1;
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xoffset[1] = -1;
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}
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if (delta_y >= 0) {
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yoffset[1] = 1;
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} else {
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delta_y = -delta_y;
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yoffset[1] = -1;
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}
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if (delta_x < delta_y) {
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sint32 tmp_var = delta_x;
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delta_x = delta_y;
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delta_y = tmp_var;
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yoffset[0] = yoffset[1];
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xoffset[1] = xoffset[0];
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xoffset[0] = 0;
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}
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max_length = delta_x;
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line_counter = delta_y + delta_y - delta_x;
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line_inc[0] = delta_y + delta_y;
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line_inc[1] = (delta_y - delta_x) * 2;
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}
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U6LineWalker::~U6LineWalker() {
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// TODO Auto-generated destructor stub
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}
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bool U6LineWalker::step() {
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if (cur_step >= max_length)
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return false;
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uint8 idx = line_counter < 0 ? 0 : 1;
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line_counter += line_inc[idx];
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cur_x += xoffset[idx];
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cur_y += yoffset[idx];
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cur_step++;
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return true;
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}
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bool U6LineWalker::next(uint32 *x, uint32 *y) {
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bool ret = step();
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*x = cur_x;
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*y = cur_y;
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return ret;
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}
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} // End of namespace Nuvie
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} // End of namespace Ultima
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