Line direction

[Flikerator]

I want the line to try and go towards the mouse, like it is now. But only draw about 20 pixels (Give or take) towards it and then stop. Does anyone know how to do that?

code:

var mx,my,mz:int var x,y:int:=200 var ch : array char of boolean colourback(black) loop        Input.KeyDown (ch)         if ch ('w') or ch ('8') then             if y < maxy - 20 then                 y += 5             end if         elsif ch ('s') or ch ('2') then             if y > 20 then                 y -= 5             end if         elsif ch ('d') or ch ('6') then             if x < maxx - 20 then                 x += 5             end if         elsif ch ('a') or ch ('4') then             if x > 20 then                 x -= 5             end if         elsif ch ('7') then             if y < maxy - 20 and x > 20 then                 y += 2                 x -= 2             end if         elsif ch ('9') then             if y < maxy - 20 and x < maxx - 20 then                 y += 2                 x += 2             end if         elsif ch ('3') then             if y > 20 and x < maxx - 20 then                 y -= 2                 x += 2             end if         elsif ch ('1') then             if y > 20 and x > 20 then                 x -= 2                 y -= 2             end if         end if Mouse.Where (mx,my,mz) Draw.Line (x,y,mx,my,yellow) delay (25) View.Update cls end loop

[Neo]

Do you want a really easy way out? Draw a black circle where the mouse pointer is after youve drawn the line.

[Flikerator]

No because I will have many different backgrounds
(Not just colours, like actually pictured backgrounds.

[Flikerator]

Can someone help me out here?

[Martin]

Sure. It's easy with a bit of trig.

So let's say that you want your line to be of length L and the start and end points are (x1, y1) and (x2, y2) respectively.

Now, you can calculate the length of line (x1, y1, x2, y2) with pythagarus easily enough. Let's call that M.

Now you can draw a line (x1, y1, x2, y2) easily, but you want a line that is a stretch of that line. That is, you want a line that is scaled by a factor of 'L/M'

So your line will be: (x1, y1, x1 + (x2 - x1) * (L/M), y1 + (y2 - y1) * (L/M))

Hope it helps.

[Drakain Zeil]

Math.Distance ?

[Flikerator]

code:

var x2, y2, mz : int var x1, y1 : int := 200 var M, L : real := 5 var m, l : int := 5 var ch : array char of boolean colourback (black) View.Set ("offscreenonly") loop     Input.KeyDown (ch)     if ch ('w') or ch ('8') then         if y1 < maxy - 20 then             y1 += 5         end if     elsif ch ('s') or ch ('2') then         if y1 > 20 then             y1 -= 5         end if     elsif ch ('d') or ch ('6') then         if x1 < maxx - 20 then             x1 += 5         end if     elsif ch ('a') or ch ('4') then         if x1 > 20 then             x1 -= 5         end if     elsif ch ('7') then         if y1 < maxy - 20 and x1 > 20 then             y1 += 2             x1 -= 2         end if     elsif ch ('9') then         if y1 < maxy - 20 and x1 < maxx - 20 then             y1 += 2             x1 += 2         end if     elsif ch ('3') then         if y1 > 20 and x1 < maxx - 20 then             y1 -= 2             x1 += 2         end if     elsif ch ('1') then         if y1 > 20 and x1 > 20 then             x1 -= 2             y1 -= 2         end if     end if     Mouse.Where (x2, y2, mz)     L := Math.Distance (x1, y1, x2, y2)     M := Math.Distance (x1, y1, x2, y2)     colour (white)     locate (1, 1)     put round (L)     put round (M)     Draw.Line (x1, y1, x1 + (x2 - x1) * (L div M), y1 + (y2 - y1) * (L div M), brightgreen)     Draw.FillOval (x1, y1, 10, 10, yellow)     delay (25)     View.Update     cls end loop

Alright when I read that M/L thing this is what I came up with. It doesn't work correctly because both my "M" and "L" are the same. Which one do I change and how?

[Martin]

Don't use div.

Divide, multiply and then round the result down.

20 * (2 div 4) = 0, but round (20 * (2/4)) = 10

[Flikerator]

What absolutely must I change. Because I changed the div to "/" and tried a phew other things but im still just stabbing in the dark at what to do. Thanks for all the help though

[Flikerator]

Cervantes helped me out. We gots it to work yay ^^ Looks awsome too

I also added a sprint feature with energy : D So I can add that into my zombie game.

[Flikerator]

Ive been working on this for half an hour or so. It is probably a really easy answer but I can't figure it out. I need it to face the opposite direction of the mouse but only go a certain length.

I already have it going towards it but I need it to go away. If you need me to post more of the code just say so.

code:

Draw.Line (x1, y1, x1 + round ((x2 - x1) * (L / M)), y1 + round ((y2 - y1) * (L / M)), 22) M := Math.Distance (x1,y1,x2,y2)

[Cervantes]

30 minutes? That sucks.
It's the same code, just subtract the round ((x2 - x1) stuff instead of add it. Same with y.

code:

Draw.Line (x1, y1, x1 - round ((x2 - x1) * (L / M)), y1 - round ((y2 - y1) * (L / M)), 22)