Irrlicht Engine

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//! Finds the collision point of a line and lots of triangles, if there is one.
bool CSceneCollisionManager::getCollisionPoint(const core::line3d<f32>& ray,
	ITriangleSelector* selector, core::vector3df& outIntersection,
	core::triangle3df& outTriangle)
{
	if (!selector)
	{
		_IRR_IMPLEMENT_MANAGED_MARSHALLING_BUGFIX;
		return false;
	}

	s32 totalcnt = selector->getTriangleCount();
	Triangles.set_used(totalcnt);

	s32 cnt = 0;
	selector->getTriangles(Triangles.pointer(), totalcnt, cnt, ray);

	core::vector3df linevect = ray.getVector().normalize();
                core::vector3df intersection;
	f32 nearest = 9999999999999.0f;
	bool found = false;
	f32 tmp;
    
	for( s32 i = 0; i < cnt; ++i )
	{
		if( Triangles[i].getIntersectionWithLine( ray.start, linevect, intersection ) )
		{
			if( intersection.isBetweenPoints( ray.start, ray.end ) )
			{
				tmp = (f32)intersection.getDistanceFromSQ( ray.start );

				if( tmp < nearest )
				{
					nearest = tmp;
					outTriangle = Triangles[i];
					outIntersection = intersection;
					found = true;
				}
			}
		}
	}

	_IRR_IMPLEMENT_MANAGED_MARSHALLING_BUGFIX;
	return found;
}

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bool isOnSameSide(const vector3d<T>& p1, const vector3d<T>& p2, 
	const vector3d<T>& a, const vector3d<T>& b) const
{
	vector3d<T> bminusa = b - a;
	vector3d<T> cp1 = bminusa.crossProduct(p1 - a);
	vector3d<T> cp2 = bminusa.crossProduct(p2 - a);
	return (cp1.dotProduct(cp2) >= 0.0f);
}

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bool getIntersectionOfPlaneWithLine(const vector3d<T>& linePoint,
	const vector3d<T>& lineVect, vector3d<T>& outIntersection) const
{
	vector3d<T> normal = getNormal().normalize();
	T t2 = normal.dotProduct( lineVect );

	if( t2 == 0.0f )
		return false;

	T d = pointA.dotProduct( normal );
	T t = -( normal.dotProduct( linePoint ) - d ) / t2;
	outIntersection = linePoint + (lineVect * t);
	return true;
}

Code: Select all

//! Tests if the box intersects with a line
//! \return Returns true if there is an intersection and false if not.
bool intersectsWithLine(const vector3d<T>& linemiddle, 
						const vector3d<T>& linevect,
						T halflength) const
{
	const vector3d<T> e = getExtent(); 
	const vector3d<T> t = getCenter() - linemiddle;
	float r;

	if ((fabs(t.X) > e.X + halflength * fabs(linevect.X)) || 
		(fabs(t.Y) > e.Y + halflength * fabs(linevect.Y)) ||
		(fabs(t.Z) > e.Z + halflength * fabs(linevect.Z)) )
		return false;

	r = e.Y * (T)fabs(linevect.Z) + e.Z * (T)fabs(linevect.Y);
	if (fabs(t.Y*linevect.Z - t.Z*linevect.Y) > r )
		return false;

	r = e.X * (T)fabs(linevect.Z) + e.Z * (T)fabs(linevect.X);
	if (fabs(t.Z*linevect.X - t.X*linevect.Z) > r )
		return false;

	r = e.X * (T)fabs(linevect.Y) + e.Y * (T)fabs(linevect.X);
	if (fabs(t.X*linevect.Y - t.Y*linevect.X) > r)
		return false;

	return true;
}