topical media & game development
lib-flex-animation-code-04-GridView2.ax
lib-flex-animation-code-04-GridView2.ax
(swf
)
[ flash
]
flex
package
{
import flash.display.Sprite;
import flash.events.MouseEvent;
Serves as a visual representation of a grid of nodes used in a pathfinding solution.
public class @ax-lib-flex-animation-code-04-GridView2 extends Sprite
{
private var _cellSize:int = 20;
private var _grid:Grid;
Constructor.
public function @ax-lib-flex-animation-code-04-GridView2(grid:Grid)
{
_grid = grid;
for(var i:int = 0; i < _grid.numCols; i++)
{
for(var j:int = 0; j < _grid.numRows; j++)
{
var mult:Number = Math.sin(i * .25) + Math.cos(j * .2 + i * .05);
_grid.getNode(i, j).costMultiplier = Math.abs(mult) + 1;
}
}
drawGrid();
findPath();
addEventListener(MouseEvent.CLICK, onGridClick);
}
Draws the given grid, coloring each cell according to its state.
public function drawGrid():void
{
graphics.clear();
for(var i:int = 0; i < _grid.numCols; i++)
{
for(var j:int = 0; j < _grid.numRows; j++)
{
var node:Node = _grid.getNode(i, j);
graphics.lineStyle(0);
graphics.beginFill(getColor(node));
graphics.drawRect(i * _cellSize, j * _cellSize, _cellSize, _cellSize);
}
}
}
Determines the color of a given node based on its state.
private function getColor(node:Node):uint
{
if(!node.walkable) return 0;
if(node == _grid.startNode) return 0x666666;
if(node == _grid.endNode) return 0x666666;
var shade:Number = 300 - 70 * node.costMultiplier;
return shade << 16 | shade << 8 | shade;
}
Handles the click event on the GridView. Finds the clicked on cell and toggles its walkable state.
private function onGridClick(event:MouseEvent):void
{
var xpos:int = Math.floor(event.localX / _cellSize);
var ypos:int = Math.floor(event.localY / _cellSize);
_grid.setWalkable(xpos, ypos, !_grid.getNode(xpos, ypos).walkable);
drawGrid();
findPath();
}
Creates an instance of AStar and uses it to find a path.
private function findPath():void
{
var astar:AStar = new AStar();
if(astar.findPath(_grid))
{
// showVisited(astar);
showPath(astar);
}
}
Highlights all nodes that have been visited.
private function showVisited(astar:AStar):void
{
var visited:Array = astar.visited;
for(var i:int = 0; i < visited.length; i++)
{
graphics.beginFill(0xcccccc);
graphics.drawRect(visited[i].x * _cellSize, visited[i].y * _cellSize, _cellSize, _cellSize);
graphics.endFill();
}
}
Highlights the found path.
private function showPath(astar:AStar):void
{
var path:Array = astar.path;
for(var i:int = 0; i < path.length; i++)
{
graphics.lineStyle(0);
graphics.beginFill(0);
graphics.drawCircle(path[i].x * _cellSize + _cellSize / 2,
path[i].y * _cellSize + _cellSize / 2,
_cellSize / 3);
}
}
}
}
(C) Æliens
18/6/2009
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.
