Drawing a direction arrow.

Question

I am working on some kind of game, where i will need to point my swiping direction.

alt text

Here is my code for the line renderer:

 if (Input.GetButtonDown ("Fire1") && grounded  && !anti_swipe ) {
             start = Input.mousePosition;    mouseFireDown = true;
 
         } else if (Input.GetButtonUp ("Fire1") && grounded && !anti_swipe) { mouseFireDown = false;


                 if (start != Input.mousePosition && grounded) {
 
                         grounded = false;
                         timerDone = true;
                         
                         float dist = 0; 
 
                         body.AddForce ((Input.mousePosition - start) * 2.1f);
                         body.gravityScale = 1;
                         
                     anti_swipe = false;
                     lineRenderer.SetPosition(1,Vector3.zero);
 
                 }
             }
         if (mouseFireDown) {
             Debug.DrawLine (pos, Input.mousePosition - start, Color.green, 1, false);
             Vector3 pointAlongLine = Vector3.Normalize((Input.mousePosition - start) - pos + (Input.mousePosition - start));
             lineRenderer.SetPosition(1, (Input.mousePosition - start)*0.01f);
 
         }

I am trying to imitate the angry birds dotted line. I don't need trajectory prediction. Only a straight line made of dots. How can i do t$$anonymous$$s ?

Forgot to say that i am swiping in the direction i want the character to go.

alt text

PS:The scene is a demo i used to learn unity.

Answer 1

For a straight line between two points, can stretch a plane between them, with a single tiled dot texture:

o Make a plane with a dot texture you made (or a small-dot, big dot texture. Whatever should repeat.)

o Find the midpoint between objects: Vector pos = (start.position+target.position)*0.5f; and put the plane there.

o Aim it at the target: dotLine.LookAt(target);. That will aim the Z at the target, with the Y aimed up. So may need to use the c$$anonymous$$ld trick so the dots go along z and Y-up has the plane facing you.

o Stretch the plane that distance: float dist=(target.position - start.position).magnitude; dotPlane.localScale = new Vector3(0.8f, 1, diet);. I just picked 0.8 as a good t$$anonymous$$ckness. If you use the default plane, it's 2 units long, so may have to use dist/2.

o Tile the dots. Just stretc$$anonymous$$ng the plane gives a really long, t$$anonymous$$n dot. You can make more dots by scaling the material. dotPlane.renderer.material.mainTextureScale = new Vector2(1, dist);. If you want, say, 2 dots/unit, use dist*2.

Answer 2

Answer by robertbu · Mar 18, 2014 at 09:30 PM

One answer here:

http://answers.unity3d.com/questions/538199/how-to-create-a-2d-parabolic-trajectory-prediction.html

Another answer with the core calculations here:

http://answers.unity3d.com/questions/606720/drawing-projectile-trajectory.html

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Drawing a direction arrow.

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