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/* $Id$ */
/*
* 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 base.cpp Implementation of the base for all blitters. */
#include "../stdafx.h"
#include "base.hpp"
/**
* Draw a line with a given colour.
* @param video The destination pointer (video-buffer).
* @param x The x coordinate from where the line starts.
* @param y The y coordinate from where the line starts.
* @param x2 The x coordinate to where the line goes.
* @param y2 The y coordinate to where the lines goes.
* @param screen_width The width of the screen you are drawing in (to avoid buffer-overflows).
* @param screen_height The height of the screen you are drawing in (to avoid buffer-overflows).
* @param colour A 8bpp mapping colour.
*/
void Blitter::DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour)
{
int dy;
int dx;
int stepx;
int stepy;
int frac;
dy = (y2 - y) * 2;
if (dy < 0) {
dy = -dy;
stepy = -1;
} else {
stepy = 1;
}
dx = (x2 - x) * 2;
if (dx < 0) {
dx = -dx;
stepx = -1;
} else {
stepx = 1;
}
if (x >= 0 && y >= 0 && x < screen_width && y < screen_height) this->SetPixel(video, x, y, colour);
if (dx > dy) {
frac = dy - (dx / 2);
while (x != x2) {
if (frac >= 0) {
y += stepy;
frac -= dx;
}
x += stepx;
frac += dy;
if (x >= 0 && y >= 0 && x < screen_width && y < screen_height) this->SetPixel(video, x, y, colour);
}
} else {
frac = dx - (dy / 2);
while (y != y2) {
if (frac >= 0) {
x += stepx;
frac -= dy;
}
y += stepy;
frac += dx;
if (x >= 0 && y >= 0 && x < screen_width && y < screen_height) this->SetPixel(video, x, y, colour);
}
}
}
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