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rewilding #20

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ktyl wants to merge 8 commits from rewilding into main
pull from: rewilding
merge into: ktyl:main
Conversation 0 Commits 8 Files Changed 14 +104 -90
2 changed files with 104 additions and 90 deletions
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100
half-earth/scripts/HeatSystem.cs Normal file
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@ -0,0 +1,100 @@
using Godot;
public class HeatSystem
{
private readonly TileGrid _tiles;
private readonly float _diffusionCoefficient;
private float[] _nextTemperatures = null;
public HeatSystem(TileGrid tiles, float diffusionCoefficient)
{
_tiles = tiles;
_diffusionCoefficient = diffusionCoefficient;
_nextTemperatures = new float[tiles.Count];
}
public void Process()
{
GenerateHeat();
Diffuse();
}
private float TransferHeat(float t0, float alpha, float nx, float ny, float px, float py)
{
float d2tdx2 = nx - 2 * t0 + px;
float d2tdy2 = ny - 2 * t0 + py;
return t0 + alpha * (d2tdx2 + d2tdy2);
}
private void GetNeighbourTemperatures(int x, int y, out float nx, out float ny, out float px, out float py)
{
// default value
var t = _tiles[x, y].temperature;
nx = x > 0 ? _tiles[x - 1, y].temperature : t;
px = x < _tiles.Size - 1 ? _tiles[x + 1, y].temperature : t;
ny = y > 0 ? _tiles[x, y - 1].temperature : t;
py = y < _tiles.Size - 1 ? _tiles[x, y + 1].temperature : t;
}
private void GenerateHeat()
{
for (int i = 0; i < _tiles.Count; i++)
{
var tile = _tiles[i];
var type = tile.type;
tile.temperature += type.HeatGeneration;
ApplyHeatDamage(ref tile);
_tiles[i] = tile;
}
}
private void ApplyHeatDamage(ref Tile tile)
{
if (!(tile.type is IDamageable damageable))
return;
var surplus = tile.temperature - damageable.Threshold;
if (surplus < 0)
return;
// TODO: parameterised balancing
tile.currentHealth -= surplus;
tile.currentHealth = Mathf.Clamp(tile.currentHealth, 0, 1);
}
private void Diffuse()
{
var D = _diffusionCoefficient;
for (int i = 0; i < _tiles.Count; i++)
{
float t = _tiles[i].temperature;
_tiles.MapIndex(i, out var x, out var y);
GetNeighbourTemperatures(
x, y,
out var nx,
out var ny,
out var px,
out var py);
var temperature = TransferHeat(t, D, nx, ny, px, py);
// TODO: what if it's really really cold out?
temperature = Mathf.Max(0, temperature);
_nextTemperatures[i] = temperature;
}
for (int i = 0; i < _tiles.Count; i++)
{
var tile = _tiles[i];
tile.temperature = _nextTemperatures[i];
_tiles[i] = tile;
}
}
}

94
half-earth/scripts/WorldGrid.cs
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@ -16,13 +16,12 @@ public class WorldGrid : Node2D
[Export]
public float DiffusionCoefficient { get; set; } = 0.01f;
private float[] _nextValues = null;
public struct TileView
{
public ShaderMaterial material;
}
private TileView[] _tileViews;
private HeatSystem _heat;
// Called when the node enters the scene tree for the first time.
public override void _Ready()
@ -30,6 +29,8 @@ public class WorldGrid : Node2D
_tileGrid = (TileGrid)_tileGridResource;
GenerateCanvasItems(_tileGrid);
_heat = new HeatSystem(_tileGrid, DiffusionCoefficient);
}
#region Positioning
@ -53,8 +54,6 @@ public class WorldGrid : Node2D
var tile = _tileGrid[idx];
tile.type = tileType;
_tileGrid[x, y] = tile;
_tileViews[idx].material.SetShaderParam("lowColor", tileType.Color);
}
#endregion
@ -76,7 +75,6 @@ public class WorldGrid : Node2D
this.Clear();
_tileViews = new TileView[grid.Count];
_nextValues = new float[grid.Count];
for (int i = 0; i < grid.Count; i++)
{
@ -96,95 +94,11 @@ public class WorldGrid : Node2D
TileView view = default;
view.material = (ShaderMaterial)canvasItem.Material;
//view.material.SetShaderParam("lowColor", _tileGrid.StartTileType.Color);
_tileViews[i] = view;
}
}
public ShaderMaterial GetTileMaterial(int idx) => _tileViews[idx].material;
#region Simulation
public void _on_Clock_OnTick(int ticks)
{
GenerateHeat();
Diffuse();
}
private float TransferHeat(float t0, float alpha, float nx, float ny, float px, float py)
{
float d2tdx2 = nx - 2 * t0 + px;
float d2tdy2 = ny - 2 * t0 + py;
return t0 + alpha * (d2tdx2 + d2tdy2);
}
private void GetNeighbourTemperatures(int x, int y, out float nx, out float ny, out float px, out float py)
{
// default value
var t = _tileGrid[x, y].temperature;
nx = x > 0 ? _tileGrid[x - 1, y].temperature : t;
px = x < _tileGrid.Size - 1 ? _tileGrid[x + 1, y].temperature : t;
ny = y > 0 ? _tileGrid[x, y - 1].temperature : t;
py = y < _tileGrid.Size - 1 ? _tileGrid[x, y + 1].temperature : t;
}
private void ApplyHeatDamage(ref Tile tile)
{
if (!(tile.type is IDamageable damageable))
return;
var surplus = tile.temperature - damageable.Threshold;
if (surplus < 0)
return;
// TODO: parameterised balancing
tile.currentHealth -= surplus;
tile.currentHealth = Mathf.Clamp(tile.currentHealth, 0, 1);
}
private void GenerateHeat()
{
for (int i = 0; i < _tileGrid.Count; i++)
{
var tile = _tileGrid[i];
var type = tile.type;
tile.temperature += type.HeatGeneration;
ApplyHeatDamage(ref tile);
_tileGrid[i] = tile;
}
}
private void Diffuse()
{
var D = DiffusionCoefficient;
for (int i = 0; i < _tileGrid.Count; i++)
{
float t = _tileGrid[i].temperature;
_tileGrid.MapIndex(i, out var x, out var y);
GetNeighbourTemperatures(
x, y,
out var nx,
out var ny,
out var px,
out var py);
var temperature = TransferHeat(t, D, nx, ny, px, py);
// TODO: what if it's really really cold out?
temperature = Mathf.Max(0, temperature);
_nextValues[i] = temperature;
}
for (int i = 0; i < _tileGrid.Count; i++)
{
var tile = _tileGrid[i];
tile.temperature = _nextValues[i];
_tileGrid[i] = tile;
}
}
#endregion
public void _on_Clock_OnTick(int ticks) => _heat.Process();
}