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mod_live2d/source_code/Cubism/Framework/CubismPhysicsJson.cs
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2026-09-10 10:59:37 +03:00

241 lines
11 KiB
C#

using System;
using System.Collections.Generic;
using System.Text.Json;
namespace Cthangover.Live2D.Cubism.Framework
{
/// <summary>
/// Physics input/output dimensionality.
/// </summary>
public enum CubismPhysicsSource { X, Y, Angle }
/// <summary>
/// Normalization range for mapping raw parameter values to normalized physics inputs.
/// </summary>
public struct CubismPhysicsNormalization { public float Minimum; public float Maximum; public float Default; }
/// <summary>
/// A single particle in a physics chain. Holds position, velocity, force accumulators,
/// and per-particle properties (mobility, delay, acceleration, radius) from the
/// .physics3.json file. Positions are computed relative to the chain anchor.
/// </summary>
public struct CubismPhysicsParticle
{
public float InitialX, InitialY;
public float Mobility;
public float Delay;
public float Acceleration;
public float Radius;
public float PositionX, PositionY;
public float LastPositionX, LastPositionY;
public float LastGravityX, LastGravityY;
public float ForceX, ForceY;
public float VelocityX, VelocityY;
}
/// <summary>
/// A sub-rig groups a contiguous range of inputs, outputs, and particles
/// that form one independent physics chain. Each sub-rig has its own
/// normalization settings for position and angle inputs.
/// </summary>
public struct CubismPhysicsSubRig
{
public int InputCount, OutputCount, ParticleCount;
public int BaseInputIndex, BaseOutputIndex, BaseParticleIndex;
public CubismPhysicsNormalization NormalizationPosition;
public CubismPhysicsNormalization NormalizationAngle;
}
/// <summary>
/// Maps a model parameter to a physics chain input (X, Y, or angle)
/// with a configurable weight and optional reflection.
/// </summary>
public struct CubismPhysicsInput
{
public string ParameterId;
public int SourceParameterIndex;
public float Weight;
public CubismPhysicsSource Type;
public bool Reflect;
}
/// <summary>
/// Maps a physics chain output back to a model parameter.
/// Defines which particle vertex to read, the output type (X, Y, angle),
/// translation scale, weight, and reflection.
/// </summary>
public struct CubismPhysicsOutput
{
public string ParameterId;
public int DestinationParameterIndex;
public int VertexIndex;
public float TranslationScaleX, TranslationScaleY;
public float AngleScale;
public float Weight;
public CubismPhysicsSource Type;
public bool Reflect;
public float ValueBelowMinimum;
public float ValueExceededMaximum;
}
/// <summary>
/// Complete physics rig data structure. Holds all sub-rigs, flattened
/// input/output/particle arrays, and global gravity/wind/fps settings.
/// Used by <see cref="CubismPhysics"/> as its internal state.
/// </summary>
public class CubismPhysicsRig
{
public List<CubismPhysicsSubRig> SubRigs = new();
public List<CubismPhysicsInput> Inputs = new();
public List<CubismPhysicsOutput> Outputs = new();
public CubismPhysicsParticle[] Particles = System.Array.Empty<CubismPhysicsParticle>();
public float GravityX, GravityY;
public float WindX, WindY;
public float Fps;
}
/// <summary>
/// JSON parser for the Cubism .physics3.json format.
/// Reads the Meta section (fps, gravity, wind) and the PhysicsSettings
/// array (sub-rigs with their inputs, outputs, and vertices/particles).
///
/// All data is accessed through typed out-parameter methods that
/// parse JSON elements directly — avoiding intermediate allocation
/// of temporary data structures.
/// </summary>
public class CubismPhysicsJson
{
private readonly JsonDocument _json;
/// <summary>
/// Parses the given .physics3.json bytes.
/// </summary>
public CubismPhysicsJson(byte[] jsonBytes)
{
_json = JsonDocument.Parse(jsonBytes);
}
/// <summary>Physics simulation FPS from the Meta section, default 30.</summary>
public float GetFps()
{
var meta = _json.RootElement.GetProperty("Meta");
return meta.TryGetProperty("Fps", out var v) ? v.GetSingle() : 30f;
}
/// <summary>Number of sub-rig entries in PhysicsSettings.</summary>
public int GetSubRigCount() =>
_json.RootElement.TryGetProperty("PhysicsSettings", out var arr) ? arr.GetArrayLength() : 0;
/// <summary>Reads gravity vector from Meta.EffectiveForces.Gravity. Defaults to (0, -1).</summary>
public void GetGravity(out float x, out float y)
{
x = 0; y = -1;
var meta = _json.RootElement.GetProperty("Meta");
if (meta.TryGetProperty("EffectiveForces", out var ef) &&
ef.TryGetProperty("Gravity", out var g))
{
x = g.TryGetProperty("X", out var gx) ? gx.GetSingle() : 0f;
y = g.TryGetProperty("Y", out var gy) ? gy.GetSingle() : -1f;
}
}
/// <summary>Reads wind vector from Meta.EffectiveForces.Wind. Defaults to (0, 0).</summary>
public void GetWind(out float x, out float y)
{
x = 0; y = 0;
var meta = _json.RootElement.GetProperty("Meta");
if (meta.TryGetProperty("EffectiveForces", out var ef) &&
ef.TryGetProperty("Wind", out var w))
{
x = w.TryGetProperty("X", out var wx) ? wx.GetSingle() : 0f;
y = w.TryGetProperty("Y", out var wy) ? wy.GetSingle() : 0f;
}
}
/// <summary>Number of input entries in the given sub-rig.</summary>
public int GetInputCount(int subRigIndex) =>
GetSubRig(subRigIndex).GetProperty("Input").GetArrayLength();
/// <summary>Number of output entries in the given sub-rig.</summary>
public int GetOutputCount(int subRigIndex) =>
GetSubRig(subRigIndex).GetProperty("Output").GetArrayLength();
/// <summary>Number of vertex/particle entries in the given sub-rig.</summary>
public int GetVertexCount(int subRigIndex) =>
GetSubRig(subRigIndex).GetProperty("Vertices").GetArrayLength();
/// <summary>Reads position normalization (min, max, default) for the given sub-rig.</summary>
public void GetNormalizationPosition(int subRigIndex, out CubismPhysicsNormalization norm)
{
norm = default;
var sr = GetSubRig(subRigIndex);
if (!sr.TryGetProperty("Normalization", out var n)) return;
if (!n.TryGetProperty("Position", out var pos)) return;
norm.Minimum = pos.TryGetProperty("Minimum", out var p) ? p.GetSingle() : -30f;
norm.Maximum = pos.TryGetProperty("Maximum", out var pp) ? pp.GetSingle() : 30f;
norm.Default = pos.TryGetProperty("Default", out var pd) ? pd.GetSingle() : 0f;
}
/// <summary>Reads angle normalization (min, max, default) for the given sub-rig.</summary>
public void GetNormalizationAngle(int subRigIndex, out CubismPhysicsNormalization norm)
{
norm = default;
var sr = GetSubRig(subRigIndex);
if (!sr.TryGetProperty("Normalization", out var n)) return;
if (!n.TryGetProperty("Angle", out var angle)) return;
norm.Minimum = angle.TryGetProperty("Minimum", out var p) ? p.GetSingle() : -30f;
norm.Maximum = angle.TryGetProperty("Maximum", out var pp) ? pp.GetSingle() : 30f;
norm.Default = angle.TryGetProperty("Default", out var pd) ? pd.GetSingle() : 0f;
}
/// <summary>Reads a single input entry: parameter ID, weight, type, reflect flag.</summary>
public void GetInput(int subRigIndex, int inputIndex, out string parameterId, out float weight,
out CubismPhysicsSource type, out bool reflect)
{
var inp = GetSubRig(subRigIndex).GetProperty("Input")[inputIndex];
parameterId = inp.GetProperty("Source").GetProperty("Id").GetString();
weight = inp.TryGetProperty("Weight", out var w) ? w.GetSingle() : 1f;
type = ParseSource(inp.TryGetProperty("Type", out var t) ? t.GetString() : "X");
reflect = inp.TryGetProperty("Reflect", out var r) && r.GetBoolean();
}
/// <summary>Reads a single output entry: destination parameter ID, vertex index, scales, type, reflect.</summary>
public void GetOutput(int subRigIndex, int outputIndex, out string parameterId, out int vertexIndex,
out float scaleX, out float scaleY, out float weight, out CubismPhysicsSource type, out bool reflect)
{
var outp = GetSubRig(subRigIndex).GetProperty("Output")[outputIndex];
parameterId = outp.GetProperty("Destination").GetProperty("Id").GetString();
vertexIndex = outp.TryGetProperty("VertexIndex", out var v) ? v.GetInt32() : 0;
scaleX = scaleY = outp.TryGetProperty("Scale", out var s) ? s.GetSingle() : 1f;
weight = outp.TryGetProperty("Weight", out var w) ? w.GetSingle() : 1f;
type = ParseSource(outp.TryGetProperty("Type", out var t) ? t.GetString() : "X");
reflect = outp.TryGetProperty("Reflect", out var r) && r.GetBoolean();
}
/// <summary>Reads a single particle/vertex: mobility, delay, acceleration, radius, position.</summary>
public void GetParticle(int subRigIndex, int vertexIndex,
out float mobility, out float delay, out float acceleration, out float radius,
out float posX, out float posY)
{
var verts = GetSubRig(subRigIndex).GetProperty("Vertices")[vertexIndex];
mobility = verts.TryGetProperty("Mobility", out var m) ? m.GetSingle() : 1f;
delay = verts.TryGetProperty("Delay", out var d) ? d.GetSingle() : 0f;
acceleration = verts.TryGetProperty("Acceleration", out var a) ? a.GetSingle() : 1f;
radius = verts.TryGetProperty("Radius", out var r) ? r.GetSingle() : 1f;
var pos = verts.GetProperty("Position");
posX = pos.TryGetProperty("X", out var px) ? px.GetSingle() : 0f;
posY = pos.TryGetProperty("Y", out var py) ? py.GetSingle() : 0f;
}
private JsonElement GetSubRig(int index) =>
_json.RootElement.GetProperty("PhysicsSettings")[index];
private static CubismPhysicsSource ParseSource(string v) => v switch
{
"Angle" => CubismPhysicsSource.Angle,
"Y" => CubismPhysicsSource.Y,
_ => CubismPhysicsSource.X
};
}
}