some-pathfinding/index-old.html at master · tommy-couzens/some-pathfinding · GitHub

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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
<!DOCTYPE html>
<html>
<head>
	<title>Flow field</title>
	<canvas id="canvas" width="1050px" height="700px" style="border:1px solid #000000;"></canvas>
	<script src="VectorsOld.js"></script>


</head>
<body>

<script type="text/javascript">

//Create a 30x20 grid of cells where each cells can have values

Cell = function(x, y) {
	Vector.call(this, x, y); //gives x, y propoerties like a vector
	this.distance = null; //the distance from the target cell
	this.direction = zeroVector; // the direction vector to the neighbouring cell with the least distance
}
Cell.prototype = new Vector(); //Cells inherit vector functions

Cell.prototype.neighboursOf = function() {}

//Create a grid of cells
var grid = new Array();
var gridWidth = 30;
var gridHeight = 20;

//each cell's co-ords are at it's centre
function generateGrid(gridWidth, gridHeight) {
	for (var x = 0; x < gridWidth; x++) {
			var arr = new Array();
			for (var y = 0; y < gridHeight; y++) {
				arr[y] = new Cell(x,y);
			}
			grid[x] = arr;
		}
}
generateGrid(gridWidth, gridHeight);


//Create some our agents doing the pathfinding

var agents = new Array();

Agent = function(x, y) {
	Vector.call(this, x, y);
	this.velocity = zeroVector;
	this.rotation = 0;
	this.maxForce = 0.075;
	this.maxSpeed = 0.075;
	this.radius = 12;
	this.width = 30;
	this.height = 30;
}
Agent.prototype = new Vector();
//create agents
for (var x = 0; x < 2; x++) {
	for (var y = 0; y < 9; y++) {
		agents.push(new Agent(3*x + 2, 2*y + 2))
	}
}
/*
for (var i = 0; i < 9; i ++) {
	agents.push(new Agent(1, i*2 + 2));
}
*/

//Give the cell the agents are heading towards
var pathEnd = grid[26][10];

//Create some random obstacles in the form of towers
var towers = new Array();

function buildTowers() {
	for (var i = 0; i < 150; i++) {
		var x = parseInt(Math.random()*gridWidth);
		var y = parseInt(Math.random()*gridHeight);
		var validSpot = true;
		//don't place where agents start
		for (var j = 0; j < agents.length; j++) {
			if (agents[j].x == x && agents[j].y == y) {
				validSpot = false;
			}
		}
		//don't place at the destionation
		if (pathEnd.x == x && pathEnd.y == y) {
			validSpot = false;
		}
		if (validSpot) {
			towers.push(new Vector(x, y));
		}
	}
}
buildTowers();


//Helper method. Returns true if this grid location in bounds
function isInBounds(x, y) {
	return x >= 0 && y >= 0 && x < gridWidth && y < gridHeight;
}


//function that finds adjacent (but not diagonal) cells and returns an array of them
function neighboursOf(vector) {
	var v = vector;
	var x = v.x;
	var y = v.y;
	var neighbours = new Array();

	if (isInBounds(x - 1, y)){
		neighbours.push(grid[x - 1][y]);
	}
	if (isInBounds(x, y - 1)){
		neighbours.push(grid[x][y - 1]);
	}
	if (isInBounds(x + 1, y)){
		neighbours.push(grid[x + 1][y]);

	}
	if (isInBounds(x, y + 1)){
		neighbours.push(grid[x][y + 1]);
	}
	return neighbours;
}


//Helper method. Returns true if this grid location is on the grid and not impassable
function isValid(x, y) {
	return x >= 0 && y >= 0 && x < gridWidth && y < gridHeight && grid[x][y].distance != Number.MAX_VALUE;
}


//Returns the non-obstructed neighbours of the given grid location.
//Diagonals are only included if their neighbours are also not obstructed
function allNeighboursOf(v) {
	var res = [],
		x = v.x,
		y = v.y;

	var left = isValid(x - 1, y),
		up = isValid(x, y - 1),
		right = isValid(x + 1, y),
		down = isValid(x, y + 1);


	//We test each straight direction, then subtest the next one clockwise

	if (left) {
		res.push(grid[x - 1][y]);

		//left up
		if (up && isValid(x - 1, y - 1)) {
			res.push(grid[x - 1][y - 1]);
		}
	}
	if (up) {
		res.push(grid[x][y - 1])

		//up right
		if (right && isValid(x + 1, y- 1)) {
			res.push(grid[x + 1][y - 1]);
		}
	}
	if (right) {
		res.push(grid[x + 1][y])

		//right down
		if (down && isValid(x + 1, y + 1)) {
			res.push(grid[x + 1][y + 1]);
		}
	}
	if (down) {
		res.push(grid[x][y + 1])

		//down left
		if (left && isValid(x - 1, y + 1)) {
			res.push(grid[x - 1][y + 1]);
		}
	}

	return res;
}


//Give each cell a distance from the pathEnd using a dijkstra grid
function generateDijkstraGrid() {
	//Set all places where towers are as being weight MAXINT, which will stand for not being able to go there
	for (var i = 0; i < towers.length; i++) {
		var t = towers[i];
		grid[t.x][t.y].distance = Number.MAX_VALUE;
	}
	//flood fill from the end point
	pathEnd.distance = 0;

	var toVisit = [pathEnd]; //array which will have more cells added to it

	//for each node we need to visit, starting with the pathEnd
	for (i = 0; i < toVisit.length; i++) {
		var neighbours = neighboursOf(toVisit[i]);

		//for each neighbour of this cell
		for (var j = 0; j < neighbours.length; j++) {
			var n = neighbours[j];

			//if unvisted make it's distance the current cell being visted plus one
			if (n.distance == null) {
				n.distance = toVisit[i].distance + 1;
				toVisit.push(n);
			}
		}
	}
}
generateDijkstraGrid();

function generateFlowField() {
	for (var x = 0; x < gridWidth; x++) {
		for (var y = 0; y < gridHeight; y++) {

			var cell = grid[x][y]

			//Obstacles have no flow value; leave the direction as the zero vector
			if (cell.distance == Number.MAX_VALUE) {
				continue;
			}

			var neighbours = allNeighboursOf(cell);

			//Go through all neighbours and find the one with the lowest distance
			var min = null;
			var minDist = 0;
			for (var i = 0; i < neighbours.length; i++) {
				var n = neighbours[i];
				var dist = n.distance - cell.distance;

				if (dist < minDist && n.distance != null) {
					min = n;
					minDist = dist;
				}
			}
			//If we found a valid neighbour, point in its direction
			if (min != null) {
				cell.direction = min.minus(cell).norm();
			}
		}
	}
}
generateFlowField();

console.log(pathEnd.direction);

function steeringBehaviourFlowField(agent) {
	//Work out the force to apply to us based on the flow field grid cells we are on.
	//we apply bilinear interpolation on the 4 grid square cells directions nearest to us to work out our force
	// http://en.wikipedia.org/wiki/Bilinear_interpolation#Nonlinear

	var floor = agent.floor(); //Coordinate of the top left square centre out of the 4
	var x = floor.x;
	var y = floor.y;

	//The 4 weights we'll interpolate, first setting to 0 incase they aren't in bounds
	var f00 = zeroVector;
	var f01 = zeroVector;
	var f10 = zeroVector;
	var f11 = zeroVector;
	//If statements to check for going out of bounds
	if (isInBounds(x, y)) {
		f00 = grid[floor.x][floor.y].direction;
	};
	if (isInBounds(x, y + 1)) {
		f01 = grid[floor.x][floor.y + 1].direction;
	}
	if (isInBounds(x + 1, y))  {
		f10 = grid[floor.x +1][floor.y].direction;
	}
	if (isInBounds(x + 1, y + 1)) {
		f11 = grid[floor.x + 1][floor.y + 1].direction;
	}
	//Do the x interpolations
	var xWeight = agent.x - floor.x;

	var top = f00.mul(1 - xWeight).plus(f10.mul(xWeight)); // f00*(1-w) + f10*(w)
	var bottom = f01.mul(1 - xWeight).plus(f11.mul(xWeight)) //f01*(1-w) + f11*(w)

	//Do the y interpolation
	var yWeight = agent.y - floor.y;

	//This is now the direction we want to be travelling in
	var direction = top.mul(1 - yWeight).plus(bottom.mul(yWeight)).norm();

	//If we are centered on a grid square with no vector this will happen
	if (isNaN(direction.magnitude())) {
		return zeroVector;
	}
	var desiredVelocity = direction.mul(agent.maxSpeed);

	//The velocity change we want
	var velocityChange = desiredVelocity.minus(agent.velocity);
	//Convert to a force
	return velocityChange.mul(agent.maxForce / agent.maxSpeed);
}

//Steers the agent towards grid cells with lower cost
function steeringBehaviourLowestCost(agent) {

	//Do nothing if the agent isn't moving
	if (agent.velocity.magnitude() == 0) {
		return zeroVector;
	}
	var floor = agent.floor(); //Coordinate of the top left square centre out of the 4
	var x = floor.x;
	var y = floor.y;

	//Find our 4 closest neighbours and get their distance value
	var f00 = Number.MAX_VALUE;
	var f01 = Number.MAX_VALUE;
	var f10 = Number.MAX_VALUE;
	var f11 = Number.MAX_VALUE;

	if (isValid(x, y)) {
		f00 = grid[x][y].distance;
	};
	if (isValid(x, y + 1)) {
		f01 = grid[x][y + 1].distance;
	}
	if (isValid(x + 1, y))  {
		f10 = grid[x +1][y].distance;
	}
	if (isValid(x + 1, y + 1)) {
		f11 = grid[x + 1][y + 1].distance;
	}

	//Find the position(s) of the lowest, there may be multiple
	var minVal = Math.min(f00, f01, f10, f11);
	var minCoord = [];

	if (f00 == minVal) {
		minCoord.push(floor.plus(new Vector(0, 0)));
	}
	if (f01 == minVal) {
		minCoord.push(floor.plus(new Vector(0, 1)));
	}
	if (f10 == minVal) {
		minCoord.push(floor.plus(new Vector(1, 0)));
	}
	if (f11 == minVal) {
		minCoord.push(floor.plus(new Vector(1, 1)));
	}


	//Tie-break by choosing the one we are most aligned with
	var currentDirection = agent.velocity.norm();
	var desiredDirection =  zeroVector;
	minVal = Number.MAX_VALUE;
	for (var i = 0; i < minCoord.length; i++) {
		//the direction to the coord from the agent
		var directionTo = minCoord[i].minus(agent).norm();
		//the magnitude of difference from the current vector to direction of the coord from the agent
		var magnitude = directionTo.minus(currentDirection).magnitude();
		//if it's the smallest magnitude, set it as the desiredDirection
		if (magnitude < minVal) {
			minVal = magnitude;
			desiredDirection = directionTo;
		}
	}

	//Convert to a force
	var force = desiredDirection.mul(agent.maxForce / agent.maxSpeed);
	return force;
}
console.log(agents[0].__proto__);

function moveAgents() {
	for (var i = 0; i < agents.length; i++) {
		var a = agents[i];

		//Work out the force for our behaviour
		var flowField = steeringBehaviourFlowField(a);
		var lowestCost = steeringBehaviourLowestCost(a);
		var force = (flowField.mul(0.97) ).plus( lowestCost.mul(0.03)); //seems to be pretty perfect with only skipping diagonals 0.25 of a square before the end

		//Apply the force
		a.velocity = a.velocity.plus(force);

		//Cap speed as required
		var speed = a.velocity.magnitude();
		if (speed > a.maxSpeed) {
			a.velocity = a.velocity.mul(a.maxSpeed/speed);
		}
		//Calculate our new movement angle
		a.rotation = a.velocity.angle();

		//Move a bit
		a.x += a.velocity.x;
		a.y += a.velocity.y;

	}
}


//
//
//
//
//
//
//
//
//DRAWING

var canvas = document.getElementById('canvas')
var ctx = document.getElementById('canvas').getContext('2d');

//Literally just drawing lines
function drawGridLines() {
	ctx.strokeStyle = "black";
	for (var x = 0; x < gridWidth; x++){
		ctx.beginPath();
		ctx.moveTo(x*35, 0);
		ctx.lineTo(x*35, gridHeight*35);
		ctx.stroke();
		}
	for (var y = 0; y < gridHeight; y++){
		ctx.beginPath();
		ctx.moveTo(0, y*35);
		ctx.lineTo(gridWidth*35, y*35);
		ctx.stroke();
		}
}

function drawAgents() {

	for (var i = 0; i < agents.length; i++) {
		var a = agents[i];
		//save the state
		ctx.save();

		//draw a circle
		ctx.beginPath();
		ctx.arc(a.x*35 + 17.5, a.y*35 + 17.5, a.radius, 0, 2*Math.PI,true);
		ctx.closePath();
		ctx.lineWidth = 2
		ctx.strokeStyle = "black";
		ctx.stroke()

		//draw an arrow inside to indicate velocity
		//arrow line
		ctx.beginPath();
		ctx.moveTo(a.x*35 + 17.5, a.y*35 + 17.5);
		ctx.lineTo(a.x*35 + 17.5 + a.radius*Math.cos(a.rotation), a.y*35 + 17.5 + a.radius*Math.sin(a.rotation));
		ctx.stroke();
		//arrow head

		//restore back to original stage
		ctx.restore();
	}
}


function drawTowers() {
	for (i = 0; i < towers.length; i++) {
		var t = towers[i];
		ctx.beginPath();
		ctx.arc(t.x*35 + 17.5, t.y*35 + 17.5, 15, 0, 2*Math.PI,true);
		ctx.closePath();
		ctx.fillStyle = "green";
		ctx.fill()
	}
}


//Writes the cell distance value in eachcell
function drawCellDistances() {
	for (var x = 0; x < gridWidth; x++) {
		for (var y = 0; y < gridHeight; y++) {
			grid.font = '10px'
			if (grid[x][y].distance <= 1000 && grid[x][y].distance >= 0) {
				//check if the distance is an integer, otherwise display to 2 decimal places
				ctx.fillText(grid[x][y].distance, grid[x][y].x*35 + 11, (grid[x][y].y)*35 + 21)
			}
		}
	}
}


//Draws a line on each square to represent the flow vector
function drawFlowField() {

	for (var x = 0; x < gridWidth; x++) {
		for (var y = 0; y < gridHeight; y++) {
			f = grid[x][y];
			ctx.beginPath();
			ctx.moveTo(x*35 + 17.5, y*35 + 17.5)
			ctx.lineTo(x*35 + 17.5 + f.direction.x*17.5, y*35 + 17.5 + f.direction.y*17.5)
			ctx.strokeStyle = "blue"
			ctx.stroke();
		}
	}
}

function runAnimation() {
	//clear the frame
	ctx.clearRect(0,0, gridWidth*35, gridHeight*35);

	//draw shit
	drawGridLines();
	drawAgents();
	drawTowers();
	drawCellDistances();
	drawFlowField();
	moveAgents();

	window.requestAnimationFrame(runAnimation);
}

function setup() {
	console.log("fart poop");
}
setup()
window.requestAnimationFrame(runAnimation);


</script>

</body>
</html>