using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using FarseerPhysics.Dynamics;
using FarseerPhysics.Collision;
using FarseerPhysics.Factories;
namespace FarseerPhysics.Common
{
public enum Decomposer
{
Bayazit,
CDT,
Earclip,
Flipcode,
Seidel,
}
/// <summary>
/// Return true if the specified color is inside the terrain.
/// </summary>
public delegate bool TerrainTester(Color color);
/// <summary>
/// Simple class to maintain a terrain.
/// </summary>
public class MSTerrain
{
/// <summary>
/// World to manage terrain in.
/// </summary>
public World World;
/// <summary>
/// Center of terrain in world units.
/// </summary>
public Vector2 Center;
/// <summary>
/// Width of terrain in world units.
/// </summary>
public float Width;
/// <summary>
/// Height of terrain in world units.
/// </summary>
public float Height;
/// <summary>
/// Points per each world unit used to define the terrain in the point cloud.
/// </summary>
public int PointsPerUnit;
/// <summary>
/// Points per cell.
/// </summary>
public int CellSize;
/// <summary>
/// Points per sub cell.
/// </summary>
public int SubCellSize;
/// <summary>
/// Number of iterations to perform in the Marching Squares algorithm.
/// Note: More then 3 has almost no effect on quality.
/// </summary>
public int Iterations = 2;
/// <summary>
/// Decomposer to use when regenerating terrain. Can be changed on the fly without consequence.
/// Note: Some decomposerers are unstable.
/// </summary>
public Decomposer Decomposer;
/// <summary>
/// Point cloud defining the terrain.
/// </summary>
private sbyte[,] _terrainMap;
/// <summary>
/// Generated bodies.
/// </summary>
private List<Body>[,] _bodyMap;
private float _localWidth;
private float _localHeight;
private int _xnum;
private int _ynum;
private AABB _dirtyArea;
private Vector2 _topLeft;
public MSTerrain(World world, AABB area)
{
World = world;
Width = area.Extents.X * 2;
Height = area.Extents.Y * 2;
Center = area.Center;
}
/// <summary>
/// Initialize the terrain for use.
/// </summary>
public void Initialize()
{
// find top left of terrain in world space
_topLeft = new Vector2(Center.X - (Width * 0.5f), Center.Y - (-Height * 0.5f));
// convert the terrains size to a point cloud size
_localWidth = Width * PointsPerUnit;
_localHeight = Height * PointsPerUnit;
_terrainMap = new sbyte[(int)_localWidth + 1, (int)_localHeight + 1];
for (int x = 0; x < _localWidth; x++)
{
for (int y = 0; y < _localHeight; y++)
{
_terrainMap[x, y] = 1;
}
}
_xnum = (int)(_localWidth / CellSize);
_ynum = (int)(_localHeight / CellSize);
_bodyMap = new List<Body>[_xnum, _ynum];
// make sure to mark the dirty area to an infinitely small box
_dirtyArea = new AABB(new Vector2(float.MaxValue, float.MaxValue), new Vector2(float.MinValue, float.MinValue));
}
/// <summary>
/// Apply a texture to the terrain using the specified TerrainTester.
/// </summary>
/// <param name="texture">Texture to apply.</param>
/// <param name="position">Top left position of the texture relative to the terrain.</param>
/// <param name="tester">Delegate method used to determine what colors should be included in the terrain.</param>
public void ApplyTexture(Texture2D texture, Vector2 position, TerrainTester tester)
{
Color[] colorData = new Color[texture.Width * texture.Height];
texture.GetData(colorData);
for (int y = (int)position.Y; y < texture.Height + (int)position.Y; y++)
{
for (int x = (int)position.X; x < texture.Width + (int)position.X; x++)
{
if (x >= 0 && x < _localWidth && y >= 0 && y < _localHeight)
{
bool inside = tester(colorData[((y - (int)position.Y) * texture.Width) + (x - (int)position.X)]);
if (!inside)
_terrainMap[x, y] = 1;
else
_terrainMap[x, y] = -1;
}
}
}
// generate terrain
for (int gy = 0; gy < _ynum; gy++)
{
for (int gx = 0; gx < _xnum; gx++)
{
//remove old terrain object at grid cell
if (_bodyMap[gx, gy] != null)
{
for (int i = 0; i < _bodyMap[gx, gy].Count; i++)
{
World.RemoveBody(_bodyMap[gx, gy][i]);
}
}
_bodyMap[gx, gy] = null;
//generate new one
GenerateTerrain(gx, gy);
}
}
}
/// <summary>
/// Apply a texture to the terrain using the specified TerrainTester.
/// </summary>
/// <param name="position">Top left position of the texture relative to the terrain.</param>
public void ApplyData(sbyte[,] data, Vector2 position)
{
for (int y = (int)position.Y; y < data.GetUpperBound(1) + (int)position.Y; y++)
{
for (int x = (int)position.X; x < data.GetUpperBound(0) + (int)position.X; x++)
{
if (x >= 0 && x < _localWidth && y >= 0 && y < _localHeight)
{
_terrainMap[x, y] = data[x, y];
}
}
}
// generate terrain
for (int gy = 0; gy < _ynum; gy++)
{
for (int gx = 0; gx < _xnum; gx++)
{
//remove old terrain object at grid cell
if (_bodyMap[gx, gy] != null)
{
for (int i = 0; i < _bodyMap[gx, gy].Count; i++)
{
World.RemoveBody(_bodyMap[gx, gy][i]);
}
}
_bodyMap[gx, gy] = null;
//generate new one
GenerateTerrain(gx, gy);
}
}
}
/// <summary>
/// Convert a texture to an sbtye array compatible with ApplyData().
/// </summary>
/// <param name="texture">Texture to convert.</param>
/// <param name="tester"></param>
/// <returns></returns>
public static sbyte[,] ConvertTextureToData(Texture2D texture, TerrainTester tester)
{
sbyte[,] data = new sbyte[texture.Width, texture.Height];
Color[] colorData = new Color[texture.Width * texture.Height];
texture.GetData(colorData);
for (int y = 0; y < texture.Height; y++)
{
for (int x = 0; x < texture.Width; x++)
{
bool inside = tester(colorData[(y * texture.Width) + x]);
if (!inside)
data[x, y] = 1;
else
data[x, y] = -1;
}
}
return data;
}
/// <summary>
/// Modify a single point in the terrain.
/// </summary>
/// <param name="location">World location to modify. Automatically clipped.</param>
/// <param name="value">-1 = inside terrain, 1 = outside terrain</param>
public void ModifyTerrain(Vector2 location, sbyte value)
{
// find local position
// make position local to map space
Vector2 p = location - _topLeft;
// find map position for each axis
p.X = p.X * _localWidth / Width;
p.Y = p.Y * -_localHeight / Height;
if (p.X >= 0 && p.X < _localWidth && p.Y >= 0 && p.Y < _localHeight)
{
_terrainMap[(int)p.X, (int)p.Y] = value;
// expand dirty area
if (p.X < _dirtyArea.LowerBound.X) _dirtyArea.LowerBound.X = p.X;
if (p.X > _dirtyArea.UpperBound.X) _dirtyArea.UpperBound.X = p.X;
if (p.Y < _dirtyArea.LowerBound.Y) _dirtyArea.LowerBound.Y = p.Y;
if (p.Y > _dirtyArea.UpperBound.Y) _dirtyArea.UpperBound.Y = p.Y;
}
}
/// <summary>
/// Regenerate the terrain.
/// </summary>
public void RegenerateTerrain()
{
//iterate effected cells
var gx0 = (int)(_dirtyArea.LowerBound.X / CellSize);
var gx1 = (int)(_dirtyArea.UpperBound.X / CellSize) + 1;
if (gx0 < 0) gx0 = 0;
if (gx1 > _xnum) gx1 = _xnum;
var gy0 = (int)(_dirtyArea.LowerBound.Y / CellSize);
var gy1 = (int)(_dirtyArea.UpperBound.Y / CellSize) + 1;
if (gy0 < 0) gy0 = 0;
if (gy1 > _ynum) gy1 = _ynum;
for (int gx = gx0; gx < gx1; gx++)
{
for (int gy = gy0; gy < gy1; gy++)
{
//remove old terrain object at grid cell
if (_bodyMap[gx, gy] != null)
{
for (int i = 0; i < _bodyMap[gx, gy].Count; i++)
{
World.RemoveBody(_bodyMap[gx, gy][i]);
}
}
_bodyMap[gx, gy] = null;
//generate new one
GenerateTerrain(gx, gy);
}
}
_dirtyArea = new AABB(new Vector2(float.MaxValue, float.MaxValue), new Vector2(float.MinValue, float.MinValue));
}
private void GenerateTerrain(int gx, int gy)
{
float ax = gx * CellSize;
float ay = gy * CellSize;
List<Vertices> polys = MarchingSquares.DetectSquares(new AABB(new Vector2(ax, ay), new Vector2(ax + CellSize, ay + CellSize)), SubCellSize, SubCellSize, _terrainMap, Iterations, true);
if (polys.Count == 0) return;
_bodyMap[gx, gy] = new List<Body>();
// create the scale vector
Vector2 scale = new Vector2(1f / PointsPerUnit, 1f / -PointsPerUnit);
// create physics object for this grid cell
foreach (var item in polys)
{
// does this need to be negative?
item.Scale(ref scale);
item.Translate(ref _topLeft);
item.ForceCounterClockWise();
Vertices p = FarseerPhysics.Common.PolygonManipulation.SimplifyTools.CollinearSimplify(item);
List<Vertices> decompPolys = new List<Vertices>();
switch (Decomposer)
{
case Decomposer.Bayazit:
decompPolys = Decomposition.BayazitDecomposer.ConvexPartition(p);
break;
case Decomposer.CDT:
decompPolys = Decomposition.CDTDecomposer.ConvexPartition(p);
break;
case Decomposer.Earclip:
decompPolys = Decomposition.EarclipDecomposer.ConvexPartition(p);
break;
case Decomposer.Flipcode:
decompPolys = Decomposition.FlipcodeDecomposer.ConvexPartition(p);
break;
case Decomposer.Seidel:
decompPolys = Decomposition.SeidelDecomposer.ConvexPartition(p, 0.001f);
break;
default:
break;
}
foreach (Vertices poly in decompPolys)
{
if (poly.Count > 2)
_bodyMap[gx, gy].Add(BodyFactory.CreatePolygon(World, poly, 1));
}
}
}
}
}
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