This is useful if you need to find the surface area of the whole mesh or want to choose triangles randomly with probability based on their relative areas. It turns out that the area of the triangle is equal to perpLength / 2. You can also normalize the perpendicular vector by dividing it by its magnitude:- var perpLength = perp.magnitude This can be done with the normalized property, but there is another trick which is occasionally useful. The result will point in exactly the opposite direction if the order of the input vectors is reversed.įor meshes, the normal vector must also be normalized. As you look down at the top side of the surface (from which the normal will point outwards) the first vector should sweep around clockwise to the second:- var perp: Vector3 = Vector3.Cross(side1, side2) The “left hand rule” can be used to decide the order in which the two vectors should be passed to the cross product function. The cross product of these two vectors will give a third vector which is perpendicular to the surface. Pick any of the three points and then subtract it from each of the two other points separately to give two vectors:- var a: Vector3 their cross product, since this way a plane is defined, which may have only one perpendicular line. Given three points in the plane, say the corner points of a mesh triangle, it is easy to find the normal. You need a second vector not parallel to the first one to find a vector perpendicular to them both, i.e. The result will point in exactly the opposite direction if the order of the input vectors is reversed. More info See in Glossary generation and may also be useful in path following and other situations. var perp: Vector3 Vector3.Cross(side1, side2). Nurbs, Nurms, Subdiv surfaces must be converted to polygons. Unity supports triangulated or Quadrangulated polygon meshes. Meshes make up a large part of your 3D worlds. Mover.position = center + new Vector2(Mathf.Cos(angle), Mathf.A normal vector (ie, a vector perpendicular to a plane) is required frequently during mesh The main graphics primitive of Unity. Choose the smaller of two angles separating the start & endįloat travel = (endAngle - startAngle + 5f * Mathf.PI) % (2f * Mathf.PI) - Mathf.PI įloat angle = startAngle + progress * travel Vector2 center = start + difference/2f + perpendicular įloat startAngle = Mathf.Atan2(toStart.y, toStart.x) įloat endAngle = Mathf.Atan2(toEnd.y, toEnd.x) Perpendicular *= Mathf.Sign(radius) * Mathf.Sqrt(radius*radius - span*span/4f) Vector2 perpendicular = new Vector2(difference.y, -difference.x)/span Override the radius if it's too small to bridge the points. IEnumerator FollowArc(įloat radius, // Set this to negative if you want to flip the arc. Myself, I'd use a circular arc for this - that way it's easy to get consistent speed. I assume that once the sun (or moon) reaches the ending point, they can just disappear from the scene, and re-appear on the next day on the starting point, so it's location until then is irrelevant. x, 0 ) i.normal normalize (i.normal) Actually, because we're normalizing anyway, we can scale our tangent vector by. x, 0 ) float h1 tex2D (HeightMap, i.uv) float h2 tex2D (HeightMap, i.uv + delta) i.normal float3 ( 1, (h2 - h1) / delta. Now substitute these points with the above example: point = startingPoint Let's directly use that as our normal vector. The control point should be located above the mountains, but the exact value depends on what kind of curve you are looking for. If you want to create moving objects like a sun and a moon, create 3 Vector3 points: starting point (where the sun begins travelling) an ending point (where the sun ends up) and a control point (that controls the curve). MyObject.position = Vector3.Lerp(m1, m2, count) īasically, to compute a Quadratic Bezier Curve (one with three points) you have to find the interpolated points of it's two lines, construct a line with those two points (The green line in the gif), and interpolate again to find a final point.Īs you can see, if you increase the Y value on your second point, the curve will be bigger. Vector3 m2 = Vector3.Lerp( point, point, count ) Vector3 m1 = Vector3.Lerp( point, point, count ) Then to compute the curve in a script for an object to travel to it, do this: float count = 0.0f Point = point +(point -point)/2 +Vector3.up *5.0f // Play with 5.0 to change the curve Use sorting layers and order in layers of sprite renderers to make things appear in a different order. Assuming point and point are your starting point and destination It automatically converts to a Vector3 with the Z value as 0f when required. In your example you can create the point between your two given points, plus some height. Given 2 given points, you have to define one third point yourself that controls where the curve is made.
0 Comments
Leave a Reply. |