www.pudn.com > IntroductionTo3DGameEngineDesign.rar > Quad.cs
using System;
using System.Collections;
using System.Drawing;
using Microsoft.DirectX;
using Microsoft.DirectX.Direct3D;
namespace GameEngine
{
///
/// The basic structure for building a Quadtree
///
public class Quad : IDisposable
{
private Rectangle m_Bounds;
private Quad m_NorthEast = null;
private Quad m_NorthWest = null;
private Quad m_SouthWest = null;
private Quad m_SouthEast = null;
private Quad m_Parent = null;
private int m_nLevel;
private SortedList m_Objects;
private float m_fRadius;
private Vector3 m_vPosition;
private string m_sName;
private static Quad m_BaseQuad = null;
public String Name { get { return m_sName; } }
public Rectangle Bounds { get { return m_Bounds; } }
public Quad(Rectangle bounds, int level, int maxlevel, Quad parent )
{
if ( m_BaseQuad == null )
{
m_BaseQuad = this;
}
m_Bounds = bounds;
m_nLevel = level;
m_Parent = parent;
m_Objects = new SortedList();
m_sName = "L" + level + ":X" + bounds.Left + "Y" + bounds.Top;
m_vPosition.X = (bounds.Left + bounds.Right) / 2.0f;
m_vPosition.Y = 0.0f;
m_vPosition.Z = (bounds.Top + bounds.Bottom) / 2.0f;
double dx = bounds.Width;
double dz = bounds.Height;
m_fRadius = (float)Math.Sqrt( dx * dx + dz * dz ) / 2.0f;
if ( level < maxlevel )
{
int nHalfHeight = (int)dz / 2;
int nHalfWidth = (int)dx / 2;
m_NorthEast = new Quad (
new Rectangle(bounds.Left + nHalfWidth, bounds.Top, nHalfWidth, nHalfHeight),
level+1, maxlevel, this );
m_NorthWest = new Quad (
new Rectangle(bounds.Left, bounds.Top, nHalfWidth, nHalfHeight),
level+1, maxlevel, this);
m_SouthWest = new Quad (
new Rectangle(bounds.Left, bounds.Top + nHalfHeight, nHalfWidth, nHalfHeight),
level+1, maxlevel, this);
m_SouthEast = new Quad (
new Rectangle(bounds.Left + nHalfWidth, bounds.Top + nHalfHeight, nHalfWidth, nHalfHeight),
level+1, maxlevel, this);
}
}
public void AddObject( Object3D obj )
{
try
{
if ( obj != null )
{
if ( obj.InRect( m_Bounds ) )
{
int nIndex = m_Objects.IndexOfKey( obj.Name );
try
{
if ( nIndex < 0 ) // add object if we don't have it yet
{
m_Objects.Add(obj.Name, obj );
obj.m_Quads.Add(this);
// if ( !obj.Name.StartsWith("Quad") && !obj.Name.StartsWith("tree") && !obj.Name.StartsWith("red")&& !obj.Name.StartsWith("blue"))
// {
// Console.AddLine(obj.Name + " added to " + Name );
// }
if ( m_NorthEast != null && obj.InRect( m_NorthEast.Bounds ) )
{
m_NorthEast.AddObject( obj );
}
if ( m_NorthWest != null && obj.InRect( m_NorthWest.Bounds ) )
{
m_NorthWest.AddObject( obj );
}
if ( m_SouthWest != null && obj.InRect( m_SouthWest.Bounds ) )
{
m_SouthWest.AddObject( obj );
}
if ( m_SouthEast != null && obj.InRect( m_SouthEast.Bounds ) )
{
m_SouthEast.AddObject( obj );
}
}
else
{
// Console.AddLine("Attempt to add another " + obj.Name );
}
}
catch (DirectXException d3de)
{
Console.AddLine("Unable to add object" );
Console.AddLine(d3de.ErrorString);
}
catch ( Exception e )
{
Console.AddLine("Unable to add object" );
Console.AddLine(e.Message);
}
}
else
{
int nIndex = m_Objects.IndexOfKey( obj.Name );
if ( nIndex >= 0 ) // remove the object if we have it
{
RemoveObject( obj );
if ( m_Parent != null )
{
m_Parent.AddObject( obj );
}
}
}
}
}
catch
{
Console.AddLine("fails in Quad AddObject");
}
}
public void RemoveObject( Object3D obj )
{
try
{
if ( obj != null )
{
int nIndex = m_Objects.IndexOfKey( obj.Name );
if ( nIndex >= 0 )
{
try
{
m_Objects.Remove( obj.Name );
}
catch
{
Console.AddLine("failing while removing object from quad object list" );
}
try
{
if ( obj.m_Quads.Count > 0 )
{
obj.m_Quads.Clear();
}
}
catch
{
Console.AddLine("failing while clearing objects quad list");
}
if ( m_NorthEast != null )
{
m_NorthEast.RemoveObject( obj );
}
if ( m_NorthWest != null )
{
m_NorthWest.RemoveObject( obj );
}
if ( m_SouthWest != null )
{
m_SouthWest.RemoveObject( obj );
}
if ( m_SouthEast != null )
{
m_SouthEast.RemoveObject( obj );
}
}
}
}
catch (DirectXException d3de)
{
Console.AddLine("Unable to remove object" );
Console.AddLine(d3de.ErrorString);
}
catch ( Exception e )
{
Console.AddLine("Unable to remove object" );
Console.AddLine(e.Message);
}
}
public void Cull( Camera cam )
{
Object3D obj;
int i;
cam.Reset();
if ( m_Objects.Count > 0 )
{
try
{
switch ( cam.CheckFrustum( m_vPosition, m_fRadius ) )
{
case Camera.CullState.AllInside:
for ( i = 0; i < m_Objects.Count; i++ )
{
obj = (Object3D)m_Objects.GetByIndex(i);
obj.Range = cam.GetDistance( obj );
obj.Culled = false;
m_Objects.SetByIndex(i, obj);
cam.AddVisibleObject( obj );
}
break;
case Camera.CullState.AllOutside:
if ( m_Parent == null ) // i.e. if this is the root quad
{
goto case Camera.CullState.PartiallyIn;
}
// do nothing since the default state is true (reset after each render)
break;
case Camera.CullState.PartiallyIn:
if ( m_NorthEast != null )
{
m_NorthEast.Cull( cam );
m_NorthWest.Cull( cam );
m_SouthWest.Cull( cam );
m_SouthEast.Cull( cam );
}
else // if partially in at the bottom level treat as in
{
for ( i = 0; i < m_Objects.Count; i++ )
{
obj = (Object3D)m_Objects.GetByIndex(i);
obj.Culled = false;
m_Objects.SetByIndex(i, obj);
cam.AddVisibleObject( obj );
}
}
break;
}
}
catch (DirectXException d3de)
{
Console.AddLine("Unable to cull object" );
Console.AddLine(d3de.ErrorString);
}
catch ( Exception e )
{
Console.AddLine("Unable to cull object" );
Console.AddLine(e.Message);
}
}
}
public void Update ( Object3D obj )
{
bool bResetNeeded = false;
try
{
// only need to reset the quad for the object if it is no longer in one of the quads
try
{
foreach ( Quad q in obj.m_Quads )
{
try
{
if ( !obj.InRect( q.m_Bounds ) )
{
bResetNeeded = true;
}
}
catch
{
Console.AddLine("invalid quad in object quad list");
}
}
}
catch
{
Console.AddLine("fails in foreach");
}
try
{
if ( bResetNeeded )
{
m_BaseQuad.RemoveObject( obj );
m_BaseQuad.AddObject( obj );
}
}
catch
{
Console.AddLine("fails in reset needed");
}
}
catch (DirectXException d3de)
{
Console.AddLine("Unable to update a Quad " + Name);
Console.AddLine(d3de.ErrorString);
}
catch ( Exception e )
{
Console.AddLine("Unable to update a Quad " + Name);
Console.AddLine(e.Message);
}
}
public void Dispose()
{
if ( m_NorthEast != null ) m_NorthEast.Dispose();
if ( m_NorthWest != null ) m_NorthWest.Dispose();
if ( m_SouthWest != null ) m_SouthWest.Dispose();
if ( m_SouthEast != null ) m_SouthEast.Dispose();
}
}
}