/*
 * C# / XNA  port of Bullet (c) 2011 Mark Neale <[email protected]>
 *
 * Bullet Continuous Collision Detection and Physics Library
 * Copyright (c) 2003-2008 Erwin Coumans  http://www.bulletphysics.com/
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from
 * the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
// Adapted from BulletXNA 73b2e1b9: namespace isolation, no XNA rendering, one type per file.
#nullable disable
#pragma warning disable CS1591, CS0168, CS0219, CS0414, CS0660, CS0661, CS0659, CS0693, CS8981, CS0108, CS0114
using System;
using HumanoidRetargeter.Core.Formats.Mmd.Bullet.LinearMath;

namespace HumanoidRetargeter.Core.Formats.Mmd.Bullet.BulletCollision;

internal class SphereShape : ConvexInternalShape
{
	public SphereShape() : this(1f)
	{
	}

	public SphereShape(float radius)
	{
		m_shapeType = BroadphaseNativeTypes.SPHERE_SHAPE_PROXYTYPE;
		m_implicitShapeDimensions.X = radius;
		m_collisionMargin = radius;
	}

	public void Initialize(float radius)
	{
		m_shapeType = BroadphaseNativeTypes.SPHERE_SHAPE_PROXYTYPE;
		m_implicitShapeDimensions.X = radius;
		m_collisionMargin = radius;
	}

	public override IndexedVector3 LocalGetSupportingVertex(ref IndexedVector3 vec)
	{
		IndexedVector3 supVertex;
		supVertex = LocalGetSupportingVertexWithoutMargin(ref vec);
		IndexedVector3 vecnorm = vec;
		if (vecnorm.LengthSquared() < (MathUtil.SIMD_EPSILON * MathUtil.SIMD_EPSILON))
		{
			vecnorm = new IndexedVector3(-1f);
		}

		vecnorm.Normalize();
		supVertex += GetMargin() * vecnorm;
		return supVertex;
	}

	public override IndexedVector3 LocalGetSupportingVertexWithoutMargin(ref IndexedVector3 vec)
	{
		return IndexedVector3.Zero;
	}

	//notice that the vectors should be unit length
	public override void BatchedUnitVectorGetSupportingVertexWithoutMargin(IndexedVector3[] vectors, IndexedVector4[] supportVerticesOut, int numVectors)
	{
		for (int i = 0; i < numVectors; i++)
		{
			supportVerticesOut[i] = IndexedVector4.Zero;
		}
	}

	public override void CalculateLocalInertia(float mass, out IndexedVector3 inertia)
	{
		float elem = 0.4f * mass * GetMargin() * GetMargin();
		inertia = new IndexedVector3(elem);
	}

	public override void GetAabb(ref IndexedMatrix t, out IndexedVector3 aabbMin, out IndexedVector3 aabbMax)
	{
		IndexedVector3 center = t._origin;
		float margin = GetMargin();
		IndexedVector3 extent = new IndexedVector3(margin);
		aabbMin = center - extent;
		aabbMax = center + extent;
	}

	public virtual float GetRadius()
	{
		return m_implicitShapeDimensions.X * m_localScaling.X;
	}

	public void SetUnscaledRadius(float radius)
	{
		m_implicitShapeDimensions.X = radius;
		SetMargin(radius);
	}

	//debugging
	public override String GetName()
	{
		return "SPHERE";
	}

	public override float GetMargin()
	{
		//to improve gjk behaviour, use radius+margin as the full margin, so never get into the penetration case
		//this means, non-uniform scaling is not supported anymore
		return GetRadius();
	}

	public override void Cleanup()
	{
		base.Cleanup();
	}
}