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https://github.com/Ellpeck/MLEM.git
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105 lines
No EOL
4.6 KiB
C#
105 lines
No EOL
4.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using Microsoft.Xna.Framework;
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using Microsoft.Xna.Framework.Graphics;
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using MLEM.Extensions;
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using MLEM.Misc;
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using MLEM.Pathfinding;
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using MLEM.Startup;
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using MLEM.Ui;
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using MLEM.Ui.Elements;
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namespace Demos {
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public class PathfindingDemo : Demo {
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private bool[,] world;
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private AStar2 pathfinder;
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private List<Point> path;
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private Button regenerateButton;
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public PathfindingDemo(MlemGame game) : base(game) {}
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private async void Init() {
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this.path = null;
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// generate a simple random world for testing, where true is walkable area, and false is a wall
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var random = new Random();
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this.world = new bool[50, 50];
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for (var x = 0; x < 50; x++) {
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for (var y = 0; y < 50; y++) {
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if (random.NextDouble() >= 0.25)
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this.world[x, y] = true;
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}
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}
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// Create a cost function, which determines how expensive (or difficult) it should be to move from a given position
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// to the next, adjacent position. In our case, the only restriction should be walls and out-of-bounds positions, which
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// both have a cost of AStar2.InfiniteCost, meaning they are completely unwalkable.
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// If your game contains harder-to-move-on areas like, say, a muddy pit, you can return a higher cost value for those
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// locations. If you want to scale your cost function differently, you can specify a different default cost in your
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// pathfinder's constructor
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float Cost(Point pos, Point nextPos) {
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if (nextPos.X < 0 || nextPos.Y < 0 || nextPos.X >= 50 || nextPos.Y >= 50)
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return AStar2.InfiniteCost;
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return this.world[nextPos.X, nextPos.Y] ? 1 : AStar2.InfiniteCost;
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}
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// Actually initialize the pathfinder with the cost function, as well as specify if moving diagonally between tiles should be
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// allowed or not (in this case it's not)
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this.pathfinder = new AStar2(Cost, false);
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// Now find a path from the top left to the bottom right corner and store it in a variable
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// If no path can be found after the maximum amount of tries (10000 by default), the pathfinder will abort and return no path (null)
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var foundPath = await this.pathfinder.FindPathAsync(Point.Zero, new Point(49, 49));
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this.path = foundPath != null ? foundPath.ToList() : null;
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// print out some info
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Console.WriteLine("Pathfinding took " + this.pathfinder.LastTriesNeeded + " tries and " + this.pathfinder.LastTimeNeeded.TotalSeconds + " seconds");
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if (this.path == null) {
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Console.WriteLine("Couldn't find a path, trying again");
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this.Init();
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}
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}
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public override void LoadContent() {
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this.regenerateButton = new Button(Anchor.TopCenter, new Vector2(30, 10), "Regenerate") {
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OnPressed = e => this.Init()
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};
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this.UiRoot.AddChild(this.regenerateButton);
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this.Init();
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}
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public override void DoDraw(GameTime gameTime) {
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this.GraphicsDevice.Clear(Color.White);
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this.SpriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.PointClamp, transformMatrix: Matrix.CreateScale(14));
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var tex = this.SpriteBatch.GetBlankTexture();
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// draw the world with simple shapes
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for (var x = 0; x < 50; x++) {
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for (var y = 0; y < 50; y++) {
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if (!this.world[x, y]) {
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this.SpriteBatch.Draw(tex, new Rectangle(x, y, 1, 1), Color.Black);
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}
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}
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}
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// draw the path
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// in a real game, you'd obviously make your characters walk along the path instead of drawing it
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if (this.path != null) {
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for (var i = 1; i < this.path.Count; i++) {
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var (firstX, firstY) = this.path[i - 1];
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var (secondX, secondY) = this.path[i];
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this.SpriteBatch.Draw(tex, RectangleF.FromCorners(new Vector2(firstX + 0.25F, firstY + 0.25F), new Vector2(secondX + 0.75F, secondY + 0.75F)), Color.Blue);
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}
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}
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this.SpriteBatch.End();
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base.DoDraw(gameTime);
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}
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public override void Clear() {
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this.UiRoot.RemoveChild(this.regenerateButton);
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}
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}
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} |