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Location: cpp/openttd-patchpack/source/src/blitter/base.cpp
r17532:020a6804ad4c
3.5 KiB
text/x-c
(svn r22306) -Fix-ish: WT3 still doesn't validate the amount of plural parameters
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | /* $Id$ */
/*
* 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"
#include "../core/math_func.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.
* @param width Line width.
*/
void Blitter::DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width)
{
int dy;
int dx;
int stepx;
int stepy;
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;
}
int frac_diff = width * max(dx, dy);
if (width > 1) {
/* compute frac_diff = width * sqrt(dx*dx + dy*dy)
* Start interval:
* max(dx, dy) <= sqrt(dx*dx + dy*dy) <= sqrt(2) * max(dx, dy) <= 3/2 * max(dx, dy) */
int frac_sq = width * width * (dx * dx + dy * dy);
int frac_max = 3 * frac_diff / 2;
while (frac_diff < frac_max) {
int frac_test = (frac_diff + frac_max) / 2;
if (frac_test * frac_test < frac_sq) {
frac_diff = frac_test + 1;
} else {
frac_max = frac_test - 1;
}
}
}
if (dx > dy) {
int y_low = y;
int y_high = y;
int frac_low = dy - frac_diff / 2;
int frac_high = dy + frac_diff / 2;
while (frac_low + dx / 2 < 0) {
frac_low += dx;
y_low -= stepy;
}
while (frac_high - dx / 2 > 0) {
frac_high -= dx;
y_high += stepy;
}
x2 += stepx;
while (x != x2) {
if (x >= 0 && x < screen_width) {
for (int y = y_low; y != y_high; y += stepy) {
if (y >= 0 && y < screen_height) this->SetPixel(video, x, y, colour);
}
}
if (frac_low >= 0) {
y_low += stepy;
frac_low -= dx;
}
if (frac_high >= 0) {
y_high += stepy;
frac_high -= dx;
}
x += stepx;
frac_low += dy;
frac_high += dy;
}
} else {
int x_low = x;
int x_high = x;
int frac_low = dx - frac_diff / 2;
int frac_high = dx + frac_diff / 2;
while (frac_low + dy / 2 < 0) {
frac_low += dy;
x_low -= stepx;
}
while (frac_high - dy / 2 > 0) {
frac_high -= dy;
x_high += stepx;
}
y2 += stepy;
while (y != y2) {
if (y >= 0 && y < screen_height) {
for (int x = x_low; x != x_high; x += stepx) {
if (x >= 0 && x < screen_width) this->SetPixel(video, x, y, colour);
}
}
if (frac_low >= 0) {
x_low += stepx;
frac_low -= dy;
}
if (frac_high >= 0) {
x_high += stepx;
frac_high -= dy;
}
y += stepy;
frac_low += dx;
frac_high += dx;
}
}
}
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