Function pointInsidePolygon

TheForceEngine/TFE_Polygon/polygon.cpp:425–496

	}

	bool pointInsidePolygon(const Polygon* poly, Vec2f p)
	{
		if (p.x < poly->bounds[0].x + eps || p.x > poly->bounds[1].x - eps || p.z < poly->bounds[0].z + eps || p.z > poly->bounds[1].z - eps)
		{
			return false;
		}

		const s32 edgeCount = (s32)poly->edge.size();
		const Edge* edge = poly->edge.data();
		const Edge* last = &edge[edgeCount - 1];
		const Vec2f* vtx = poly->vtx.data();

		const Vec2f* w0 = &vtx[last->i0];
		const Vec2f* w1 = &vtx[last->i1];
		f32 dzLast = w1->z - w0->z;
		s32 crossings = 0;

		for (s32 e = 0; e < edgeCount; e++, edge++)
		{
			w0 = &vtx[edge->i0];
			w1 = &vtx[edge->i1];

			const f32 x0 = w0->x;
			const f32 x1 = w1->x;
			const f32 z0 = w0->z;
			const f32 z1 = w1->z;
			const f32 dz = z1 - z0;

			if (dz != 0)
			{
				if (p.z == z0 && p.x == x0)
				{
					return true;
				}
				else if (p.z != z0)
				{
					if (p.z != z1)
					{
						PointSegSide side = lineSegmentSide(p, { x0, z0 }, { x1, z1 });
						if (side == PS_OUTSIDE)
						{
							crossings++;
						}
						else if (side == PS_ON_LINE)
						{
							return true;
						}
					}
					dzLast = dz;
				}
				else if (p.x != x0)
				{
					if (p.x < x0)
					{
						//f32 dzSignMatches = ((dz >= 0.0f && dzLast >= 0.0f) || (dz <= 0.0f && dzLast <= 0.0f)) ? 1.0f : -1.0f;
						bool dzSignMatches = sign(dz) == sign(dzLast);
						if (dzSignMatches || dzLast == 0)  // the signs match OR dz or dz0 are positive OR dz0 EQUALS 0.
						{