113 lines
3.5 KiB
C#
113 lines
3.5 KiB
C#
using System;
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using System.Numerics;
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using Raylib_cs;
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namespace PhysicsEngine
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{
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public class Body
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{
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public Vector2 Position;
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public Vector2 Velocity;
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public Vector2 ForceAccumulator;
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public Color BaseColor = Color.Blue;
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public float Rotation;
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public float AngularVelocity;
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public float TorqueAccumulator;
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public float Mass;
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public float InverseMass => Mass > 0.0f ? 1.0f / Mass : 0.0f;
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public float MomentOfInertia;
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public float InverseInertia => MomentOfInertia > 0.0f ? 1.0f / MomentOfInertia : 0.0f;
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public float Restitution = 0.5f;
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public float Friction = 0.2f;
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public float DragCoefficient = 0.0f; // Drag per m^2 (ignored if 0.0)
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public bool IsStatic => Mass == 0.0f;
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public void ApplyForce(Vector2 force)
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{
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if (IsStatic) return;
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ForceAccumulator += force;
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}
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public void ApplyTorque(float torque)
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{
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if (IsStatic) return;
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TorqueAccumulator += torque;
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}
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public void ApplyImpulse(Vector2 impulse)
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{
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if (IsStatic) return;
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Velocity += impulse * InverseMass;
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}
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public void ApplyImpulseAtOffset(Vector2 impulse, Vector2 localOffset)
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{
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if (IsStatic) return;
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Velocity += impulse * InverseMass;
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float cos = MathF.Cos(Rotation);
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float sin = MathF.Sin(Rotation);
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Vector2 worldOffset = new Vector2(
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localOffset.X * cos - localOffset.Y * sin,
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localOffset.X * sin + localOffset.Y * cos
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);
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float torque = worldOffset.X * impulse.Y - worldOffset.Y * impulse.X;
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AngularVelocity += torque * InverseInertia;
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}
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public void ApplyImpulseAtWorldPosition(Vector2 impulse, Vector2 worldPosition)
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{
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if (IsStatic) return;
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Velocity += impulse * InverseMass;
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Vector2 worldOffset = worldPosition - Position;
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float torque = worldOffset.X * impulse.Y - worldOffset.Y * impulse.X;
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AngularVelocity += torque * InverseInertia;
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}
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public void ApplyForceAtWorldPosition(Vector2 force, Vector2 worldPosition)
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{
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if (IsStatic) return;
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ForceAccumulator += force;
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Vector2 worldOffset = worldPosition - Position;
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float torque = worldOffset.X * force.Y - worldOffset.Y * force.X;
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TorqueAccumulator += torque;
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}
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public Vector2 GetWorldPointFromLocal(Vector2 localPoint)
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{
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float cos = MathF.Cos(Rotation);
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float sin = MathF.Sin(Rotation);
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Vector2 rotated = new Vector2(
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localPoint.X * cos - localPoint.Y * sin,
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localPoint.X * sin + localPoint.Y * cos
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);
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return Position + rotated;
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}
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public Vector2 GetLocalPointFromWorld(Vector2 worldPoint)
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{
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Vector2 delta = worldPoint - Position;
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float cos = MathF.Cos(-Rotation);
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float sin = MathF.Sin(-Rotation);
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return new Vector2(
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delta.X * cos - delta.Y * sin,
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delta.X * sin + delta.Y * cos
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);
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}
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public void ClearForces()
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{
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ForceAccumulator = Vector2.Zero;
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TorqueAccumulator = 0.0f;
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}
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public virtual void Draw(float pixelsPerMeter = 100.0f) {}
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public virtual void ApplyAerodynamicDrag(float dt) {}
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}
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} |