private void Collisions()
{
Rectangle bounds = BoundingRect;
int left = (int)Math.Floor((float)bounds.Left / Tiles.TileWidth);
int right = (int)Math.Ceiling(((float)bounds.Right / Tiles.TileWidth)) - 1;
int top = (int)Math.Floor((float)bounds.Top / Tiles.TileHeight);
int bottom = (int)Math.Ceiling(((float)bounds.Bottom / Tiles.TileHeight)) - 1;
// Reset flag to search for ground collision.
isGround = false;
// For each potentially colliding tile,
for (int y = top; y <= bottom; ++y)
{
for (int x = left; x <= right; ++x)
{
// If this tile is collidable,
TilesCollision collision = Level.Collision(x, y);
if (collision != TilesCollision.Passable)
{
// Determine collision depth (with direction) and magnitude.
Rectangle tileBounds = Level.Bounds(x, y);
Vector2 depth = RectangleExtensions.IntersectionDepth(bounds, tileBounds);
if (depth != Vector2.Zero)
{
float absDepthX = Math.Abs(depth.X);
float absDepthY = Math.Abs(depth.Y);
// Resolve the collision along the shallow axis.
if (absDepthY < absDepthX || collision == TilesCollision.Platform)
{
// If we crossed the top of a tile, we are on the ground.
if (PrevBottom <= tileBounds.Top)
{
isGround = true;
}
// Ignore platforms, unless we are on the ground.
if (collision == TilesCollision.Impassable || IsGround)
{
// Resolve the collision along the Y axis.
Position = new Vector2(Position.X, Position.Y + depth.Y);
// Perform further collisions with the new bounds.
bounds = BoundingRect;
}
}
else if (collision == TilesCollision.Impassable) // Ignore platforms.
{
// Resolve the collision along the X axis.
Position = new Vector2(Position.X + depth.X, Position.Y);
// Perform further collisions with the new bounds.
bounds = BoundingRect;
}
else if (collision == TilesCollision.Lava)
{
level.Restart();
health -= 1;
if (health <= 0)
{
Kill(null);
}
}
}
}
}
}
PrevBottom = bounds.Bottom;
}