/// <summary>
/// A teensy quadtree baby.
/// </summary>
private QuadTree(byte level, Rectangle bounds, List<PhysicalObject> objects)
{
byte level1 = level;
Rectangle bounds1 = bounds;
_center = bounds.Position + bounds.Size / 2f;
Point childSize = bounds.Size / 2f;
if (objects.Count > MaxObjects)
{
//decide in what childtree an object would fit and add it there
List<PhysicalObject> childObjects0 = new List<PhysicalObject>();
List<PhysicalObject> childObjects1 = new List<PhysicalObject>();
List<PhysicalObject> childObjects2 = new List<PhysicalObject>();
List<PhysicalObject> childObjects3 = new List<PhysicalObject>();
foreach (PhysicalObject obj in objects)
{
bool[] fits = FitObject(obj);
if (!fits[4])
{
if (fits[0])
childObjects0.Add(obj);
else if (fits[1])
childObjects1.Add(obj);
else if (fits[2])
childObjects2.Add(obj);
else
childObjects3.Add(obj);
}
else
_objects.Add(obj);
}
//create subtrees and add everything that fits inside of em
_children[0] = new QuadTree((byte)(level1 + 1), new Rectangle(bounds1.Position, childSize), childObjects0);
_children[1] = new QuadTree((byte)(level1 + 1), new Rectangle(new Point(_center.X, bounds1.Position.Y), childSize), childObjects1);
_children[2] = new QuadTree((byte)(level1 + 1), new Rectangle(new Point(bounds1.Position.X, _center.Y), childSize), childObjects2);
_children[3] = new QuadTree((byte)(level1 + 1), new Rectangle(_center, childSize), childObjects3);
}
else
_objects = objects;
}
private static void Step()
{
//push input state
Input.PushState();
//process all SDL.SDL_events
SDL.SDL_Event e;
while (SDL.SDL_PollEvent(out e) == 1)
{
switch (e.type)
{
//let Input handle input related events
case SDL.SDL_EventType.SDL_MOUSEBUTTONDOWN:
case SDL.SDL_EventType.SDL_MOUSEBUTTONUP:
case SDL.SDL_EventType.SDL_MOUSEWHEEL:
case SDL.SDL_EventType.SDL_MOUSEMOTION:
case SDL.SDL_EventType.SDL_KEYDOWN:
case SDL.SDL_EventType.SDL_KEYUP:
case SDL.SDL_EventType.SDL_TEXTINPUT:
case SDL.SDL_EventType.SDL_CONTROLLERDEVICEADDED:
case SDL.SDL_EventType.SDL_CONTROLLERDEVICEREMOVED:
case SDL.SDL_EventType.SDL_CONTROLLERBUTTONDOWN:
case SDL.SDL_EventType.SDL_CONTROLLERBUTTONUP:
case SDL.SDL_EventType.SDL_CONTROLLERAXISMOTION:
Input.InputEvent(e);
break;
//let Window handle window related events
case SDL.SDL_EventType.SDL_WINDOWEVENT:
Window.WindowEvent(e);
break;
//global quit, not only the window's exit button
case SDL.SDL_EventType.SDL_QUIT:
Exit();
break;
}
}
Input.UpdateMousePosition();
Input.ApplyButtonMaps();
foreach (GameObject obj in Resources.Objects)
{
if (!obj.Destroyed)
obj.Step();
}
//collision time!
Profiler.Start("collision");
float minX = float.PositiveInfinity;
float minY = float.PositiveInfinity;
float maxX = float.NegativeInfinity;
float maxY = float.NegativeInfinity;
foreach(PhysicalObject obj in Resources.PhysicalObjects)
{
obj.UpdateCoverableArea();
if (obj.CoverableArea.Position.X < minX)
minX = obj.CoverableArea.Position.X;
if (obj.CoverableArea.Position2.X > maxX)
maxX = obj.CoverableArea.Position2.X;
if (obj.CoverableArea.Position.Y < minY)
minY = obj.CoverableArea.Position.Y;
if (obj.CoverableArea.Position2.Y > maxY)
maxY = obj.CoverableArea.Position2.Y;
//set before the actual collision check phase
obj.SpeedLeft = 1f;
obj.CollisionCandidates = null;
}
//create and fill quadtree for this step
QuadTree = new QuadTree(new Rectangle(minX, minY, maxX - minX, maxY - minY));
//create list of objects to process and calculate all first collision speedfractions for those objects
List<PhysicalObject> processingObjects = new List<PhysicalObject>(Resources.PhysicalObjects);
foreach (PhysicalObject obj in Resources.PhysicalObjects)
{
if (obj.Speed == Point.Zero)
continue;
processingObjects.Add(obj);
obj.CalculateClosestCollision();
}
while (processingObjects.Count > 0)
{
//get closest collision, process it/the pair of objects
PhysicalObject obj = processingObjects.MinBy(o => o.ClosestCollisionSpeedFraction + 1 - o.SpeedLeft);
obj.PerformClosestCollision();
//remove/recalculate collisions
if (obj.SpeedLeft == 0f)
processingObjects.Remove(obj);
else
obj.CalculateClosestCollision();
//recalculate for all possibly influenced objects (if needed)
if (obj.CollisionCandidates != null)
{
foreach (PhysicalObject influencedObj in obj.CollisionCandidates)
influencedObj.CalculateClosestCollision();
}
}
Profiler.Stop();
Resources.ObjectAdditionAndRemoval();
Resources.CleanupFontTextures();
}
