44 lines
1.3 KiB
C#
44 lines
1.3 KiB
C#
using Microsoft.Xna.Framework;
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using System;
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using System.Collections.Generic;
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namespace SemiColinGames {
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public static class Line {
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public static void Rasterize(Point p1, Point p2, IList<Point> result) {
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Line.Rasterize(p1.X, p1.Y, p2.X, p2.Y, result);
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}
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// Rasterizes a line using Bresenham's line-drawing algorithm.
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//
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// References:
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// https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm
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// http://members.chello.at/~easyfilter/bresenham.html
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// http://members.chello.at/~easyfilter/Bresenham.pdf (section 1.6)
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public static void Rasterize(int x1, int y1, int x2, int y2, IList<Point> result) {
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int dx = Math.Abs(x2 - x1);
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int stepX = x1 < x2 ? 1 : -1;
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int dy = -Math.Abs(y2 - y1);
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int stepY = y1 < y2 ? 1 : -1;
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int error = dx + dy;
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int errorXY; // Error value e_xy from the PDF.
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int i = 0;
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result.Clear();
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result.Add(new Point(x1, y1));
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while (x1 != x2 || y1 != y2) {
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i++;
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errorXY = 2 * error;
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if (errorXY >= dy) { // e_xy + e_x > 0
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error += dy;
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x1 += stepX;
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}
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if (errorXY <= dx) { // e_xy + e_y < 0
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error += dx;
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y1 += stepY;
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}
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result.Add(new Point(x1, y1));
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}
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}
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}
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}
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