Advice

[TheOneTrueGod]

Allright, i'm programming an RPG type thing, with real time battles, and I want to make it entirely in turing (I.E. no outside graphics, meaning the game won't look too great but itll play well [I hate skeptics who only focus on graphics]) That being said, I'm trying to craft a lightning spell, and to do that I wanted to make it look fancier than just a yellow line from point A to point B. I came up with the following procedure:

code:

function Angle (x1, y1, x2, y2 : real) : real     var theta : real     if x1 = x2 then         if y2 > y1 then             theta := 90         else             theta := 270         end if     else         theta := arctand ((y1 - y2) / (x1 - x2))         if x2 > x1 then             if y2 > y1 then             else                 theta := 360 + theta             end if         else             theta := 180 + theta         end if     end if     result theta end Angle function Dist (x1, y1, x2, y2 : real) : real     result sqrt ((x2 - x1) ** 2 + (y2 - y1) ** 2) end Dist procedure DrawLightning (x, y, tx, ty : real, numforks : int)     var lx, ly, oldlx, oldly : real := x     var tempcx, tempcy : real     var angle : real := Angle (x, y, tx, ty)     var r : int     ly := y     oldly := y     var c : int := 0     loop         c += 1         lx += cosd (angle) * Dist (x, y, tx, ty) / numforks         ly += sind (angle) * Dist (x, y, tx, ty) / numforks         tempcx := lx         tempcy := ly         r := Rand.Int (-1, 1)         tempcx += cosd (angle + r * 90) * Dist (x, y, tx, ty) / numforks         tempcy += sind (angle + r * 90) * Dist (x, y, tx, ty) / numforks         exit when c > numforks         Draw.ThickLine (round (oldlx), round (oldly), round (tempcx), round (tempcy), 3, yellow)         oldlx := tempcx         oldly := tempcy     end loop end DrawLightning View.Set ('offscreenonly') loop     for i : -1 .. 1         for j : -1 .. 1             DrawLightning (maxx div 2, maxy div 2, maxx div 2 + 200 * i, maxy div 2 + 200 * j, 70)         end for     end for     View.Update     delay (30)     cls end loop

This will just draw several lightning bolts originating from the centre. I need to know some ways to improve it, because while it looks okay, it could still use some improvement.

The algorithm works basically by dividing it up into "NumForks" different sections, and just randomizing if it goes up or down on that section. Any ideas on how to make it look better, without sacrificing too much efficiency? (Also, a bit of efficiency help may be nice, but the main thing i'm looking for is graphical improvement. I know I should have made it a for loop, for example.)

[batman]

Cool program!
One thing you could do to make your code better is using arrays, it will make your code shorter. You could also add music to your program! Maybe a lightningnoice, that be cool. IF you need help doing that then send me a message.

[Delos]

batman wrote:

Cool program!
One thing you could do to make your code better is using arrays, it will make your code shorter. You could also add music to your program! Maybe a lightningnoice, that be cool. IF you need help doing that then send me a message.

Intersting concept. Now where exactly would he be using said arrays? Perhaps in lx, ly...but that would just be pushing it.

As for improvement:
I like the look of it when few forks are used. To make things a little more interesting, use a couple of other 'think lines' drawn with a larger radius behind the main one. This will add a border, and you can achieve some enticing effects.
My own intuition tells me that your parameter setup:

code:

DrawLightning (x, y, tx, ty : real, numforks : int)

would translate as positionX, positionY, sizeX, sizeY, forks. This is apparently not true though . But that's just me. Perhaps having a variable size would be advantageous?

Now, the most important critique:
Go here!. zylum's tut on recursion will open up a whole new level of leetness for you. You'll want to focus on fractal generation, since this will allow you to create more realistic lightning.

Good work so far, and keep us updated.

[Clayton]

very nice, how long did that take you to figure out, your obviously a math genius, however, whenever you finish your RPG post it, id like to give it a try, if this is a good sample of it, keep up the good work

[md]

The math looks interesting; but as I don't have turing someone want to post a screenshot?

Batman: Arrays? I can't see any use for arrays at all...
SuperFreak82: Good with math yes, math genius perhaps not. This code just demonstrates an ability to use math (one which to be fair many people seem to lack...) but I don't think it qualifies for genius level code.

One thing that might be cool; and uses recursion in psudo (Pascal/C) code:

code:

Function Lightening(s, d:point; fork_length, fork_chance, fork_angle:real; fork_count:integer) {     if( Distance(s, d) <= fork_length )             LineTo(d);         else         {             point n;             real angle = AngleTo(s, d) - (fork_angle/2);             for( int i = 1 to fork_count )             {                         n.x += s.x + cos(angle) * fork_length;          n.y += s.y + sin(angle) * fork_length;                         angle += fork_angle / fork_count;                         if( Rand(0,1) <= fork_chance)                         {                                 Line(s, n);                                 Lightening(n, d, fork_length * 0.7, fork_chance * 0.7, fork_angle *0.7, fork_count);                         }             }         } }

The 0.7's are to make it less likely to fork, and less likely to go away from the point the closer it gets.

**Edit, damned tabs. I'd fix it... but I'm lazy.
** Edit 2: It'd look better with a really wide fork angle, ~50% fork chance, high fork count, and shortish fork length.

[Cervantes]

Accidently posted in a new thread:

TheOneTrueGod wrote:

Thanks for the help. I attempted to put in recursion for it, and this is what I got. I only found one problem that I don't know how to fix. At higher "divisions" and "angle", i.e. (60 and 120 respectively), the final branch is much longer than the rest. It adds for an ok "homing in" effect, but aside from that, it looks like crap.

@Batman, if you feel like creating, or finding, or whatever a bolt sound, go for it, I will implement it into the RPG.

code:

function Angle (x1, y1, x2, y2 : real) : real     var theta : real     if x1 = x2 then         if y2 > y1 then             theta := 90         else             theta := 270         end if     else         theta := arctand ((y1 - y2) / (x1 - x2))         if x2 > x1 then             if y2 > y1 then             else                 theta := 360 + theta             end if         else             theta := 180 + theta         end if     end if     result theta end Angle function Dist (x1, y1, x2, y2 : real) : real     result sqrt ((x2 - x1) ** 2 + (y2 - y1) ** 2) end Dist procedure DrawLightning (startx, starty, x, y, exitx, exity, angle : real, exitcondition, divs, forkanglemax : int)     var x2, y2 : real     var r : int := Rand.Int (-forkanglemax, forkanglemax)     if exitcondition not= 1 then         x2 := x + cosd (angle + r) * Dist (startx, starty, exitx, exity) / divs         y2 := y + sind (angle + r) * Dist (startx, starty, exitx, exity) / divs         Draw.ThickLine (round (x), round (y), round (x2), round (y2), 3, yellow)         DrawLightning (startx, starty, x2, y2, exitx, exity, Angle (x2, y2, exitx, exity), exitcondition - 1, divs, round (forkanglemax - (forkanglemax / divs)))     else         Draw.ThickLine (round (x), round (y), round (exitx), round (exity), 3, yellow)     end if end DrawLightning procedure Lightning (x1, y1, x2, y2 : real, fork_count, fangle : int)     DrawLightning (x1, y1, x1, y1, x2, y2, Angle (x1, y1, x2, y2), fork_count, fork_count, fangle) end Lightning loop     locate (1, 1)     Lightning (100, 100, 300, 100, 25, 40)     delay (30)     cls end loop

Oh, and the header for the procedure is as follows:
Lightning(starting_x_coordinate,starting_y_coordinate,ending_x_coordinate,ending_y_coordinate,number_of_forks,max_fork_starting_angle)

Taking care of business

[[Gandalf]]

Pictures of Lightning slightly edited by me:
http://img486.imageshack.us/img486/179/lightning1ih.jpg
http://img96.imageshack.us/img96/9669/lightning28so.jpg

My attempt at converting Cornflake's code, which doesn't quite work:

code:

proc Lightning (sX, sY, dX, dY : real, fork_length, fork_chance, fork_angle : real, fork_count : int)     if Math.Distance (sX, sY, dX, dY) <= fork_length then         Draw.Line (round (sX), round (sY), round (dX), round (dY), black)     else         var nX, nY : real := 0         var angle : real := Angle (sX, sY, dX, dY) - (fork_angle / 2)         for i : 1 .. fork_count             nX += sX + cos (angle) * fork_length             nY += sY + sin (angle) * fork_length             angle += fork_angle / fork_count             if Rand.Real <= fork_chance then                 Draw.Line (round (sX), round (sY), round (nX), round (nY), black)                 Lightning (nX, nY, dX, dY, fork_length * 0.7, fork_chance * 0.7, fork_angle * 0.7, fork_count)             end if         end for     end if end Lightning Lightning (50, 100, maxx - 50, 100, 5, 0.5, 40, 50)

Not sure what I got wrong... Don't have much time to spend this minute. Think I might have gotten a int/real mixed up.

[batman]

I will begin on working on some sort of bolt sound and when im done i'll send it to you. You know what would make your code cooler is if you added falling rain in the backround. Its a suggestion. You could use blue asterisks that scroll down the screen as rain, I guess.

[Mazer]

The lightning effect would definitely benefit from a dark background. I know you said you'll be using it in a game, but consider a sort of checkerboard of black dots across the screen to make it look darker just before you start with the lightning.

The lightning itself looks nice (from the screenshots; I haven't got Turing here to see if it's animated or anything). A few things to consider here:
- try using the RGB module to get yourself a small pallete of colours, bright yellows that are close to white (or if you'd prefer instead of yellow, blue)
- thinner bolts. If it doesn't take too much time while running, try drawing the bolts as thick as they are now with one of those slightly darker colours from before, and then again thinner with a really bright colour. Just try to make the differences subtle
- fewer bolts: screenshot2 was pretty crazy, but again, I don't know if this is animated...

Keep it up!

[Clayton]

Quote:

SuperFreak82: Good with math yes, math genius perhaps not. This code just demonstrates an ability to use math (one which to be fair many people seem to lack...) but I don't think it qualifies for genius level code.

i was just stating that he obviously knew something about math, and that he is good with it, i was exagerating, and in answer to some of the above questions yes this is animated

[MysticVegeta]

Delos wrote:

Now, the most important critique:
Go here!. zylum's tut on recursion will open up a whole new level of leetness for you. You'll want to focus on fractal generation, since this will allow you to create more realistic lightning.

Interesting, recursive fractals of lightening.. now thats what I am talking about!!! heh

[[Gandalf]]

Coutsos, hehe. I made it so that there would be 100 lightning bolts in the 2nd screenshot, only my "demo". I also changed the lightning bolts to be various shades of yellow. As for animation... It's only animated as far as:
loop
draw i x lightning at random spots
clear screen
end loop

[md]

[Gandalf] wrote:

My attempt at converting Cornflake's code, which doesn't quite work:

code:

proc Lightning (sX, sY, dX, dY : real, fork_length, fork_chance, fork_angle : real, fork_count : int)     if Math.Distance (sX, sY, dX, dY) <= fork_length then         Draw.Line (round (sX), round (sY), round (dX), round (dY), black)     else         var nX, nY : real := 0         var angle : real := Angle (sX, sY, dX, dY) - (fork_angle / 2)         for i : 1 .. fork_count             nX += sX + cos (angle) * fork_length             nY += sY + sin (angle) * fork_length             angle += fork_angle / fork_count             if Rand.Real <= fork_chance then                 Draw.Line (round (sX), round (sY), round (nX), round (nY), black)                 Lightning (nX, nY, dX, dY, fork_length * 0.7, fork_chance * 0.7, fork_angle * 0.7, fork_count)             end if         end for     end if end Lightning Lightning (50, 100, maxx - 50, 100, 5, 0.5, 40, 50)

Not sure what I got wrong... Don't have much time to spend this minute. Think I might have gotten a int/real mixed up.

Couple of things I've thought about since: angles must be modulo 360; or 2PI. And the random bit towards the end means that lightening is not guarunteed to propagate all the way to the target; that needs to be fixed somehow. One way would be to count the number of forks generated; and if there weren't any then just draw a line along any random angle in the range.

[MysticVegeta]

SuperFreak82 wrote:

very nice, how long did that take you to figure out, your obviously a math genius, however, whenever you finish your RPG post it, id like to give it a try, if this is a good sample of it, keep up the good work

if you need to see a math genius, search for catalyst's old posts and his submissions.

[Clayton]

MysticVegeta wrote:

SuperFreak82 wrote:

very nice, how long did that take you to figure out, your obviously a math genius, however, whenever you finish your RPG post it, id like to give it a try, if this is a good sample of it, keep up the good work

if you need to see a math genius, search for catalyst's old posts and his submissions.

ive seen them dont you worry about that, that guy has skillz