using Microsoft.Xna.Framework; using System; namespace SemiColinGames { public static class Line { public static Point[] Rasterize(Point p1, Point p2) { return Line.Rasterize(p1.X, p1.Y, p2.X, p2.Y); } // Rasterizes a line using Bresenham's line-drawing algorithm. // // References: // https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm // http://members.chello.at/~easyfilter/bresenham.html // http://members.chello.at/~easyfilter/Bresenham.pdf (section 1.6) public static Point[] Rasterize(int x1, int y1, int x2, int y2) { int dx = Math.Abs(x2 - x1); int stepX = x1 < x2 ? 1 : -1; int dy = -Math.Abs(y2 - y1); int stepY = y1 < y2 ? 1 : -1; int error = dx + dy; int errorXY; // Error value e_xy from the PDF. // The size of the output is the size of the longer dimension, plus one. int resultSize = Math.Max(dx, -dy) + 1; var result = new Point[resultSize]; int i = 0; result[0] = new Point(x1, y1); while (x1 != x2 || y1 != y2) { i++; errorXY = 2 * error; if (errorXY >= dy) { // e_xy + e_x > 0 error += dy; x1 += stepX; } if (errorXY <= dx) { // e_xy + e_y < 0 error += dx; y1 += stepY; } result[i] = new Point(x1, y1); } return result; } } }