Exemplo n.º 1
0
        /// <summary>
        /// gets a list of all the tiles intersecting bounds. The returned list is ordered for collision detection based on the
        /// direction passed in so they can be processed in order.
        /// </summary>
        /// <returns>The colliding tiles.</returns>
        /// <param name="bounds">Bounds.</param>
        /// <param name="direction">Direction.</param>
        void populateCollidingTiles( Rectangle bounds, Edge direction )
        {
            _collidingTiles.Clear();
            var isHorizontal = direction.isHorizontal();
            var primaryAxis = isHorizontal ? Axis.X : Axis.Y;
            var oppositeAxis = primaryAxis == Axis.X ? Axis.Y : Axis.X;

            // if we are going up or left we subtract 1 from our opposite edge so that it doesnt get the column/row of tiles when we are against them
            var oppositeDirection = direction.oppositeEdge();
            var minSidePad = direction.isMin() ? -1 : 0;
            var firstPrimary = worldToTilePosition( bounds.getSide( oppositeDirection ) + minSidePad, primaryAxis );
            var lastPrimary = worldToTilePosition( bounds.getSide( direction ), primaryAxis );
            var primaryIncr = direction.isMax() ? 1 : -1;

            var min = worldToTilePosition( isHorizontal ? bounds.Top : bounds.Left, oppositeAxis );
            var mid = worldToTilePosition( isHorizontal ? bounds.getCenter().Y : bounds.getCenter().X, oppositeAxis );
            // same as above here. we subtract 1 to not grab an extra column/row of tiles which will mess up collisions
            var max = worldToTilePosition( isHorizontal ? bounds.Bottom - 1 : bounds.Right - 1, oppositeAxis );

            var isPositive = mid - min < max - mid;
            var secondaryIncr = isPositive ? 1 : -1;
            var firstSecondary = isPositive ? min : max;
            var lastSecondary = !isPositive ? min : max;

            for( var primary = firstPrimary; primary != lastPrimary + primaryIncr; primary += primaryIncr )
            {
                for( var secondary = firstSecondary; secondary != lastSecondary + secondaryIncr; secondary += secondaryIncr )
                {
                    var col = isHorizontal ? primary : secondary;
                    var row = !isHorizontal ? primary : secondary;
                    _collidingTiles.Add( _collisionLayer.getTile( col, row ) );
                }
            }
        }