private void checkVerticalCollision(Projectile p, int pxDown)
{
int forwardEdge = (int)p.Position.Y;
//1 for down, -1 for up
int yDirection = pxDown / Math.Abs(pxDown);
//start at initial forward edge
int startRow = forwardEdge / _collisionLayer.TileHeight;
//assume unit moves full distance
p.Position.Y += pxDown;
//check up to new assumed unit hitrect edge
int endRow = (forwardEdge + pxDown) / _collisionLayer.TileHeight;
startRow = (int)MathHelper.Clamp(startRow, 0, _collisionLayer.LayerHeight - 1);
endRow = (int)MathHelper.Clamp(endRow, 0, _collisionLayer.LayerHeight - 1);
for (int row = startRow; row != (endRow + yDirection); row = row + yDirection)
{
for (int col = ((int)p.Position.X + 1) / _collisionLayer.TileWidth;
col <= (p.Position.X - 1) / _collisionLayer.TileWidth;
col++)
{
//boundary checks----------------------------------------------------------------
if (col < 0)
{
p.CollideWithObstacle(Direction.West);
p.Position.X = 0;
break;
}
else if (col > _collisionLayer.LayerWidth)
{
p.CollideWithObstacle(Direction.East);
p.Position.Y = _collisionLayer.LayerWidth * _collisionLayer.TileWidth;
break;
}
if (row < 0)
{
p.CollideWithObstacle(Direction.North);
p.Position.Y = 0;
break;
}
else if (row > _collisionLayer.LayerHeight)
{
p.CollideWithObstacle(Direction.South);
p.Position.Y = _collisionLayer.LayerHeight * _collisionLayer.TileHeight;
break;
}
//--------------------------------------------------------------------------------
if (_collisionLayer.Tiles[col, row] != null && _collisionLayer.Tiles[col, row].TileIndex != 0)
{
if (pxDown > 0)
{
p.CollideWithObstacle(Direction.South);
p.Position.Y = row * _collisionLayer.TileHeight;
}
else
{
p.CollideWithObstacle(Direction.North);
p.Position.Y = (row + 1) * _collisionLayer.TileHeight;
}
break; //no need to check more
}
}
}
}
private void checkHorizontalCollision(Projectile p, int pxRight)
{
//Get the coordinate of the forward-facing edge
//If walking left, forwardEdge = left of bounding box
//If walking right, forwardEdge = right of bounding box
int forwardEdge = (int)p.Position.X;
//-1 for left, 1 for right
int xDirection = pxRight / Math.Abs(pxRight);
int startCol = forwardEdge / _collisionLayer.TileWidth;
int endCol = (forwardEdge + pxRight) / _collisionLayer.TileWidth;
startCol = (int)MathHelper.Clamp(startCol, 0, _collisionLayer.LayerWidth - 1);
endCol = (int)MathHelper.Clamp(endCol, 0, _collisionLayer.LayerWidth - 1);
p.Position.X += pxRight;
for (int col = startCol; col != (endCol + xDirection); col = col + xDirection)
{
for (int row = (int)p.Position.Y / _collisionLayer.TileHeight;
row <= p.Position.Y / _collisionLayer.TileHeight;
row++)
{
if (!_collisionLayer.IsValidTileLocation(col, row))
{
continue;
}
//within bounds -- check tile collision
else if (_collisionLayer.Tiles[col, row] != null && _collisionLayer.Tiles[col, row].TileIndex != 0)
{
if (pxRight > 0)
{
p.CollideWithObstacle(Direction.East);
p.Position.X = col * _collisionLayer.TileWidth;
}
else
{
p.CollideWithObstacle(Direction.West);
p.Position.X = (col + 1) * _collisionLayer.TileWidth;
}
break; //no need to check more
}
}
}
}
