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// Copyright (c) 2018 NVIDIA Corporation. All rights reserved.


#ifndef NVBLASTINTERNALCOMMON_H
#define NVBLASTINTERNALCOMMON_H
#include "NvBlastExtAuthoringTypes.h"
#include "NvBlastPxSharedHelpers.h"
#include <PxVec2.h>
#include <PxVec3.h>
#include <PxPlane.h>
#include <PxBounds3.h>
#include <PxMath.h>
#include <algorithm>

namespace Nv
{
namespace Blast
{

/**
Edge representation with index of parent facet
*/
struct EdgeWithParent
{
	uint32_t s, e; // Starting and ending vertices
	uint32_t parent; // Parent facet index
	EdgeWithParent() : s(0), e(0), parent(0) {}
	EdgeWithParent(uint32_t s, uint32_t e, uint32_t p) : s(s), e(e), parent(p) {}
};


/**
Comparator for sorting edges according to parent facet number.
*/
struct EdgeComparator
{
	bool operator()(const EdgeWithParent& a, const EdgeWithParent& b) const
	{
		if (a.parent == b.parent)
		{
			if (a.s == b.s)
			{
				return a.e < b.e;
			}
			else
			{
				return a.s < b.s;
			}
		}
		else
		{
			return a.parent < b.parent;
		}
	}
};

inline bool operator<(const Edge& a, const Edge& b)
{
	if (a.s == b.s)
		return a.e < b.e;
	else
		return a.s < b.s;
}

/**
Vertex projection direction flag.
*/
enum ProjectionDirections
{
	YZ_PLANE = 1 << 1,
	XY_PLANE = 1 << 2,
	ZX_PLANE = 1 << 3,

	OPPOSITE_WINDING = 1 << 4
};

/**
Computes best direction to project points.
*/
NV_FORCE_INLINE ProjectionDirections getProjectionDirection(const physx::PxVec3& normal)
{
	float maxv = std::max(std::abs(normal.x), std::max(std::abs(normal.y), std::abs(normal.z)));
	ProjectionDirections retVal;
	if (maxv == std::abs(normal.x))
	{
		retVal = YZ_PLANE;
		if (normal.x < 0) retVal = (ProjectionDirections)((int)retVal | (int)OPPOSITE_WINDING);
		return retVal;
	}
	if (maxv == std::abs(normal.y))
	{
		retVal = ZX_PLANE;
		if (normal.y > 0) retVal = (ProjectionDirections)((int)retVal | (int)OPPOSITE_WINDING);
		return retVal;
	}
	retVal = XY_PLANE;
	if (normal.z < 0) retVal = (ProjectionDirections)((int)retVal | (int)OPPOSITE_WINDING);
	return retVal;
}


/**
Computes point projected on given axis aligned plane.
*/
NV_FORCE_INLINE physx::PxVec2 getProjectedPoint(const physx::PxVec3& point, ProjectionDirections dir)
{
	if (dir & YZ_PLANE)
	{
		return physx::PxVec2(point.y, point.z);
	}
	if (dir & ZX_PLANE)
	{
		return physx::PxVec2(point.x, point.z);
	}
	return physx::PxVec2(point.x, point.y);
}

NV_FORCE_INLINE physx::PxVec2 getProjectedPoint(const NvcVec3& point, ProjectionDirections dir)
{
	return getProjectedPoint((const physx::PxVec3&)point, dir);
}

/**
Computes point projected on given axis aligned plane, this method is polygon-winding aware.
*/
NV_FORCE_INLINE physx::PxVec2 getProjectedPointWithWinding(const physx::PxVec3& point, ProjectionDirections dir)
{
	if (dir & YZ_PLANE)
	{
		if (dir & OPPOSITE_WINDING)
		{
			return physx::PxVec2(point.z, point.y);
		}
		else
		return physx::PxVec2(point.y, point.z);
	}
	if (dir & ZX_PLANE)
	{
		if (dir & OPPOSITE_WINDING)
		{
			return physx::PxVec2(point.z, point.x);
		}
		return physx::PxVec2(point.x, point.z);
	}
	if (dir & OPPOSITE_WINDING)
	{
		return physx::PxVec2(point.y, point.x);
	}
	return physx::PxVec2(point.x, point.y);
}



#define MAXIMUM_EXTENT 1000 * 1000 * 1000
#define BBOX_TEST_EPS 1e-5f 

/**
Test fattened bounding box intersetion.
*/
NV_INLINE bool  weakBoundingBoxIntersection(const physx::PxBounds3& aBox, const physx::PxBounds3& bBox)
{
	if (std::max(aBox.minimum.x, bBox.minimum.x) > std::min(aBox.maximum.x, bBox.maximum.x) + BBOX_TEST_EPS)
		return false;
	if (std::max(aBox.minimum.y, bBox.minimum.y) > std::min(aBox.maximum.y, bBox.maximum.y) + BBOX_TEST_EPS)
		return false;
	if (std::max(aBox.minimum.z, bBox.minimum.z) > std::min(aBox.maximum.z, bBox.maximum.z) + BBOX_TEST_EPS)
		return false;
	return true;
}



/**
Test segment vs plane intersection. If segment intersects the plane true is returned. Point of intersection is written into 'result'.
*/
NV_INLINE bool getPlaneSegmentIntersection(const physx::PxPlane& pl, const physx::PxVec3& a, const physx::PxVec3& b,
                                           physx::PxVec3& result)
{
	float div = (b - a).dot(pl.n);
	if (physx::PxAbs(div) < 0.0001f)
	{
		if (pl.contains(a))
		{
			result = a;
			return true;
		}
		else
		{
			return false;
		}
	}
	float t = (-a.dot(pl.n) - pl.d) / div;
	if (t < 0.0f || t > 1.0f)
	{
		return false;
	}
	result = (b - a) * t + a;
	return true;
}


#define POS_COMPARISON_OFFSET 1e-5f
#define NORM_COMPARISON_OFFSET 1e-3f
/**
Vertex comparator for vertex welding.
*/
struct VrtComp
{
	bool operator()(const Vertex& a, const Vertex& b) const
	{
		if (a.p.x + POS_COMPARISON_OFFSET < b.p.x) return true;
		if (a.p.x - POS_COMPARISON_OFFSET > b.p.x) return false;
		if (a.p.y + POS_COMPARISON_OFFSET < b.p.y) return true;
		if (a.p.y - POS_COMPARISON_OFFSET > b.p.y) return false;
		if (a.p.z + POS_COMPARISON_OFFSET < b.p.z) return true;
		if (a.p.z - POS_COMPARISON_OFFSET > b.p.z) return false;

		if (a.n.x + NORM_COMPARISON_OFFSET < b.n.x) return true;
		if (a.n.x - NORM_COMPARISON_OFFSET > b.n.x) return false;
		if (a.n.y + NORM_COMPARISON_OFFSET < b.n.y) return true;
		if (a.n.y - NORM_COMPARISON_OFFSET > b.n.y) return false;
		if (a.n.z + NORM_COMPARISON_OFFSET < b.n.z) return true;
		if (a.n.z - NORM_COMPARISON_OFFSET > b.n.z) return false;


		if (a.uv[0].x + NORM_COMPARISON_OFFSET < b.uv[0].x) return true;
		if (a.uv[0].x - NORM_COMPARISON_OFFSET > b.uv[0].x) return false;
		if (a.uv[0].y + NORM_COMPARISON_OFFSET < b.uv[0].y) return true;
		return false;
	};
};

/**
Vertex comparator for vertex welding (not accounts normal and uv parameters of vertice).
*/
struct VrtPositionComparator
{
	bool operator()(const NvcVec3& a, const NvcVec3& b) const
	{
		if (a.x + POS_COMPARISON_OFFSET < b.x) return true;
		if (a.x - POS_COMPARISON_OFFSET > b.x) return false;
		if (a.y + POS_COMPARISON_OFFSET < b.y) return true;
		if (a.y - POS_COMPARISON_OFFSET > b.y) return false;
		if (a.z + POS_COMPARISON_OFFSET < b.z) return true;
		if (a.z - POS_COMPARISON_OFFSET > b.z) return false;
		return false;
	};
	bool operator()(const Vertex& a, const Vertex& b) const
	{
		return operator()(a.p, b.p);
	};
};


NV_INLINE float calculateCollisionHullVolume(const CollisionHull& hull)
{
    if (hull.pointsCount == 0)
    {
        return 0.0f;
    }

    // Find an approximate centroid for a more accurate calculation
    NvcVec3 centroid = { 0.0f, 0.0f, 0.0f };
    for (uint32_t i = 0; i < hull.pointsCount; ++i)
    {
        centroid = centroid + hull.points[i];
    }
    centroid = centroid / hull.pointsCount;

    float volume = 0.0f;

    for (uint32_t i = 0; i < hull.polygonDataCount; ++i)
    {
        const HullPolygon& poly = hull.polygonData[i];
        if (poly.vertexCount < 3)
        {
            continue;
        }
        const uint32_t i0 = hull.indices[poly.indexBase];
        uint32_t i1 = hull.indices[poly.indexBase + 1];
        for (uint32_t j = 2; j < poly.vertexCount; ++j)
        {
            const uint32_t i2 = hull.indices[poly.indexBase + j];
            const NvcVec3 a = hull.points[i0] - centroid;
            const NvcVec3 b = hull.points[i1] - centroid;
            const NvcVec3 c = hull.points[i2] - centroid;
            volume +=
                (a.x * b.y * c.z - a.x * b.z * c.y - a.y * b.x * c.z + a.y * b.z * c.x + a.z * b.x * c.y - a.z * b.y * c.x);
            i1 = i2;
        }
    }
    return (1.0f / 6.0f) * std::abs(volume);
}

}	// namespace Blast
}	// namespace Nv

#endif