2011-04-02 13:55:54 +02:00
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/* $Id$ */
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/*
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* This file is part of OpenTTD.
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* 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.
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* 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.
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* 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/>.
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*/
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/** @file base.cpp Implementation of the base for all blitters. */
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#include "../stdafx.h"
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#include "base.hpp"
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2011-04-02 18:39:30 +02:00
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#include "../core/math_func.hpp"
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2011-04-02 13:55:54 +02:00
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/**
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* Draw a line with a given colour.
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* @param video The destination pointer (video-buffer).
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* @param x The x coordinate from where the line starts.
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* @param y The y coordinate from where the line starts.
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* @param x2 The x coordinate to where the line goes.
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* @param y2 The y coordinate to where the lines goes.
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* @param screen_width The width of the screen you are drawing in (to avoid buffer-overflows).
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* @param screen_height The height of the screen you are drawing in (to avoid buffer-overflows).
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* @param colour A 8bpp mapping colour.
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2011-04-02 18:39:30 +02:00
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* @param width Line width.
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2011-04-02 13:55:54 +02:00
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*/
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2011-04-02 18:39:30 +02:00
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void Blitter::DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width)
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2011-04-02 13:55:54 +02:00
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{
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int dy;
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int dx;
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int stepx;
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int stepy;
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dy = (y2 - y) * 2;
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if (dy < 0) {
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dy = -dy;
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stepy = -1;
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} else {
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stepy = 1;
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}
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dx = (x2 - x) * 2;
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if (dx < 0) {
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dx = -dx;
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stepx = -1;
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} else {
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stepx = 1;
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}
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2011-04-02 18:39:30 +02:00
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int frac_diff = width * max(dx, dy);
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if (width > 1) {
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int frac_sq = width * width * (dx * dx + dy * dy);
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while (frac_diff * frac_diff < frac_sq) frac_diff++;
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}
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2011-04-02 13:55:54 +02:00
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if (dx > dy) {
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2011-04-02 18:39:30 +02:00
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int y_low = y;
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int y_high = y;
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int frac_low = dy - frac_diff / 2;
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int frac_high = dy + frac_diff / 2;
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while (frac_low + dx / 2 < 0) {
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frac_low += dx;
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y_low -= stepy;
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}
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while (frac_high - dx / 2 > 0) {
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frac_high -= dx;
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y_high += stepy;
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}
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x2 += stepx;
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2011-04-02 13:55:54 +02:00
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while (x != x2) {
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if (x >= 0 && x < screen_width) {
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for (int y = y_low; y != y_high; y += stepy) {
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if (y >= 0 && y < screen_height) this->SetPixel(video, x, y, colour);
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}
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}
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if (frac_low >= 0) {
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y_low += stepy;
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frac_low -= dx;
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}
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if (frac_high >= 0) {
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y_high += stepy;
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frac_high -= dx;
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2011-04-02 13:55:54 +02:00
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}
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x += stepx;
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2011-04-02 18:39:30 +02:00
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frac_low += dy;
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frac_high += dy;
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2011-04-02 13:55:54 +02:00
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}
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} else {
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int x_low = x;
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int x_high = x;
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int frac_low = dx - frac_diff / 2;
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int frac_high = dx + frac_diff / 2;
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while (frac_low + dy / 2 < 0) {
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frac_low += dy;
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x_low -= stepx;
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}
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while (frac_high - dy / 2 > 0) {
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frac_high -= dy;
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x_high += stepx;
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}
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y2 += stepy;
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2011-04-02 13:55:54 +02:00
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while (y != y2) {
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2011-04-02 18:39:30 +02:00
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if (y >= 0 && y < screen_height) {
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for (int x = x_low; x != x_high; x += stepx) {
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if (x >= 0 && x < screen_width) this->SetPixel(video, x, y, colour);
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}
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}
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if (frac_low >= 0) {
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x_low += stepx;
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frac_low -= dy;
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}
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if (frac_high >= 0) {
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x_high += stepx;
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frac_high -= dy;
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2011-04-02 13:55:54 +02:00
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}
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y += stepy;
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2011-04-02 18:39:30 +02:00
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frac_low += dx;
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frac_high += dx;
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2011-04-02 13:55:54 +02:00
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}
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}
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}
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