Rain Code

[SNIPERDUDE]

For the game I'm making (rpg, birdseyeview) I want to make it look like it's raining for one of the sections. Because it's birdseyeview, the rain will look like its coming from the outer parts of the screen towards the centre. I don't know how to do this, and was wondering how. Please help.

[Cervantes]

Moved from [Turing Source Code].

You'll need to be familiar with arrays and trig. Records would also be good.

If you've got that, you'll need to write code that will generate a bunch of rain droplets all around the screen. All droplets will move slightly towards the centre, except those that are spawned exactly in the centre of the screen. Droplets spawned closer to the edge of the screen will move more than will rain droplets near the middle. The amount that they move will vary with the height of your view. When the droplet is first spawned, it should probably be drawn as a line with a certain length and as it falls, it's length diminishes, since we're looking more straight down on it and seeing less and less of its vertical speed.

This won't be an easy thing to code. It'll take some thought. What are your thoughts?

[Tony]

you just need a good reference for an image. The one linked is from opposite perspective (on the ground, looking up), though really the only difference is the direction the lines will be moving in the animation.

[Flikerator]

I decided to make an example; but I have a very basic problem; the angle (in radians or degrees; doesnt matter) from the starting of the rain to the center. I was then going to make it so it doens't go for the exact center but around there, and then when it gets close delete that piece of rain.

I just need the angle. I basically have the slope, but it doesn't seem to work. I might be making a mistake though somewhere else though.

I assumed the slope would be the same as the angle in radians, but that doesn't seem to be the case ^^;

Here it is anyways;

code:

[View.Set ("offscreenonly") type data_Rain :     record         x, y, angle : real     end record var Rain : flexible array 1 .. 0 of data_Rain loop     for i : 1 .. 5         new Rain, upper (Rain) + 1         var dir := Rand.Int (1, 4) %Very poorly written, just an example anywyas         if dir = 1 then             Rain (upper (Rain)).x := maxx             Rain (upper (Rain)).y := Rand.Int (0, maxy)         elsif dir = 2 then             Rain (upper (Rain)).x := 0             Rain (upper (Rain)).y := Rand.Int (0, maxy)         elsif dir = 3 then             Rain (upper (Rain)).x := Rand.Int (0, maxx)             Rain (upper (Rain)).y := maxy         else             Rain (upper (Rain)).x := Rand.Int (0, maxx)             Rain (upper (Rain)).y := 0         end if         Rain (upper (Rain)).angle := ((maxx / 2) - Rain (upper (Rain)).x) / ((maxy / 2) - Rain (upper (Rain)).y)         % put Rain (upper (Rain)).angle         % View.Update         % Input.Pause     end for     for i : 1 .. upper (Rain)         Rain (i).x += (cos (Rain (i).angle) * 2)         Rain (i).y += (sin (Rain (i).angle) * 2)         Draw.Line (round (Rain (i).x), round (Rain (i).y), round (Rain (i).x + (cos (Rain (i).angle) * 3)), round (Rain (i).y + (sin (Rain (i).angle) * 3)), blue)     end for     View.Update     delay (10)     cls end loop

[R.G.]

wow tht looks coool!

[Windsurfer]

Ooookay. doesn't really look like rain to me, yet. I'll see if i can figure something out.

[Windsurfer]

well, here's my rain. I hope you like it. I was thinking of combining it with my sparkle program for some splashing... hm, in a bit.

To be honest, i know it's not mathematical. I know it's more like me taking previous code and tweaking some variables. But it works, and i think that's what counts

I combined two of my programs together here, my sparkle engine, and my stars program.

code:

%if you want, you can change these two variables to resize the effective screen const X_SCREEN := 1024 const Y_SCREEN := 768 View.Set ("noecho") View.Set ("nobuttonbar") View.Set ("title:Stars 3D by Adam Bielinski") setscreen ("graphics:" + intstr (X_SCREEN) + ";" + intstr (Y_SCREEN)) View.Set ("position:centre,middle") View.Set ("offscreenonly") drawfillbox (-10, -10, X_SCREEN, Y_SCREEN, black) %number of drops. if you're getting a slowdown, decrease this const NUM_DROPS := 180 const TOP_HEIGHT := 400 const CUTOFF_HEIGHT := 700 const HEIGHT_VARIANCE := CUTOFF_HEIGHT - TOP_HEIGHT const FALL_SPEED := 9.8 const FOV_SIZE := 0.0001 type point_type :     record         x : real         y : real         last_x, last_y : real         life : real     end record function HowHigh : real     result         TOP_HEIGHT + HEIGHT_VARIANCE * Rand.Real end HowHigh procedure RandomizeDrop (var drops : point_type)     drops.x := Rand.Int (-X_SCREEN, 2 * X_SCREEN)     drops.y := Rand.Int (-Y_SCREEN, 2 * Y_SCREEN)     drops.life := HowHigh     drops.last_x := drops.x     drops.last_y := drops.y end RandomizeDrop var drops : array 1 .. NUM_DROPS of point_type %this is the initialatation stuff. It just puts them around on the screen at random for lp : 1 .. NUM_DROPS     RandomizeDrop (drops (lp)) end for % --------------------- this is the sparkle engin ------------------ %this is the basic engine for Bielin_Forces %this was written early in my learning of turing, so it's messy and not commented well %try it out! see what you can do! var back_color : int := black %Change either of these to a lower number if you're getting a slowdown const NUM_SPKL := 500 %this is the max number of sparkles const SPKL_RATIO := 10 %this is how many sparkles are made by clicking const SPKL_LIFE := 25 const AIR_RES := 1.5 %how fast the sparkles slow down (make it less than 1 to make them speed up!) const SPKL_GRAV := 0 %how fast they accelerate in th y plane const EXPL_FORCE := 600 %something to do with how powerful the World_Force procedure is.... hmm... type vector :     record         x : real         y : real         x_vel : real         y_vel : real         life : int         clr : int     end record var cur_spkl : int := 1 var spkl : array 1 .. NUM_SPKL of vector for lp : 1 .. NUM_SPKL     spkl (lp).x := 0     spkl (lp).y := 0     spkl (lp).x_vel := 0     spkl (lp).y_vel := 0     spkl (lp).life := SPKL_LIFE end for var global_clr : int := 104 %dark blue procedure Draw_Spkl (num, colour : int)     %drawfilloval (round (spkl (num).x), round (spkl (num).y), 3, 3, colour)     var dir_x, dir_y : real := 0     dir_x := spkl (num).x_vel     dir_y := spkl (num).y_vel     drawline (round (spkl (num).x), round (spkl (num).y),         round (spkl (num).x - dir_x), round (spkl (num).y - dir_y), colour) end Draw_Spkl procedure Run_Sparkle     for lp : 1 .. NUM_SPKL by 1         if spkl (lp).life < SPKL_LIFE then % if the sparkle needs processing, process it             %Draw_Spkl (lp, back_color)             spkl (lp).life += 1 %decrease the life of the sparkle             spkl (lp).y_vel := (spkl (lp).y_vel + SPKL_GRAV) / AIR_RES             spkl (lp).x_vel := spkl (lp).x_vel / AIR_RES             spkl (lp).y := (spkl (lp).y + spkl (lp).y_vel)             spkl (lp).x := (spkl (lp).x + spkl (lp).x_vel)             if spkl (lp).y < -50 then                 spkl (lp).life := SPKL_LIFE             end if             if spkl (lp).life < SPKL_LIFE then                 Draw_Spkl (lp, spkl (lp).clr)             end if         else             %do nothing         end if     end for end Run_Sparkle function SpklCount : int %how many sparkles are alive?     var temp1 : int := 1     for lp : 1 .. NUM_SPKL by 1         if spkl (lp).life < SPKL_LIFE then             temp1 += 1         else             %do nothing         end if     end for     result temp1 end SpklCount procedure Mk_Spkl (x1, y1 : real) %make a sparkle at a point in a random direction     var angle : real     var mag : real     if cur_spkl > NUM_SPKL then         cur_spkl := 1     end if     Draw_Spkl (cur_spkl, back_color)     spkl (cur_spkl).clr := global_clr     spkl (cur_spkl).life := 1     spkl (cur_spkl).x := x1     spkl (cur_spkl).y := y1     angle := Rand.Int (1, 360)     mag := Rand.Int (1, 190) / 10     spkl (cur_spkl).x_vel := mag * cosd (angle)     spkl (cur_spkl).y_vel := mag * sind (angle)     %this gives the sparkles a shot upwards     cur_spkl += 1 end Mk_Spkl procedure Mk_Spkl_Custom (x1, y1, x2, y2 : real) %make a sparkle at a point going in a specific direction with a specific speed     if cur_spkl > NUM_SPKL then         cur_spkl := 1     end if     Draw_Spkl (cur_spkl, back_color)     spkl (cur_spkl).clr := global_clr     spkl (cur_spkl).life := 1     spkl (cur_spkl).x := x1     spkl (cur_spkl).y := y1     spkl (cur_spkl).x_vel := x2     spkl (cur_spkl).y_vel := y2     %this gives the sparkles a shot upwards     cur_spkl += 1 end Mk_Spkl_Custom procedure World_Force (h1, v1 : int, num : real)     %this forces ALL sparkles using gravity (or colomb's law, whichever you want)     %this is a horrible medly of math X(     %it could Easily be simplified, but it works, and i don't feel like it lol     var dist : real     for lp : 1 .. NUM_SPKL         dist := sqrt ((spkl (lp).x - h1) ** 2 + (spkl (lp).y - v1) ** 2)         if round (spkl (lp).x) not= h1 then             spkl (lp).x_vel += ((spkl (lp).x - h1) / ((dist ** 2) /                 EXPL_FORCE)) * (num / 30)         end if         if round (spkl (lp).y) not= v1 then             spkl (lp).y_vel += ((spkl (lp).y - v1) / ((dist ** 2) /                 EXPL_FORCE)) * (num / 30)         end if     end for end World_Force % ---------------------- end of sparkle engine --------------- var mouse_x, mouse_y, button : int := 0 var last_time : real := Time.Elapsed const MIDX := X_SCREEN div 2 const MIDY := Y_SCREEN div 2 loop     Run_Sparkle     for lp : 1 .. NUM_DROPS         drops (lp).x := (drops (lp).x - MIDX) * (1 - drops (lp).life * FOV_SIZE) + MIDX         drops (lp).y := (drops (lp).y - MIDY) * (1 - drops (lp).life * FOV_SIZE) + MIDY         drops (lp).life += FALL_SPEED         Draw.Line (round (drops (lp).x), round (drops (lp).y),             round (drops (lp).last_x), round (drops (lp).last_y), brightblue)         if drops (lp).life >= CUTOFF_HEIGHT then             for lp2 : 1 .. Rand.Int(1,5) %splash                 Mk_Spkl (drops (lp).x, drops (lp).y)             end for             RandomizeDrop (drops (lp))         end if         drops (lp).last_x := drops (lp).x         drops (lp).last_y := drops (lp).y     end for     View.Update     drawfillbox (-10, -10, X_SCREEN, Y_SCREEN, black)     loop         exit when Time.Elapsed - last_time > 30     end loop     last_time := Time.Elapsed end loop

[Windsurfer]

What? That's a really cool effect up there. Has no one tried it? What do people think? Common people, i put a good hour of work into that

[razrdude]

Windsurfer that looks awesome, ^^ also the disperse when it hits the ground is amazing.
lol @ Flikerator good job too, but it looks like bugs crawling.

[[Gandalf]]

Windsurfer wrote:

What? That's a really cool effect up there. Has no one tried it? What do people think? Common people, i put a good hour of work into that

T'is quite nice, the splash effect especially.

Though it pains me to see such code:

code:

%if you want, you can change these two variables to resize the effective screen const X_SCREEN := 1024 const Y_SCREEN := 768 View.Set ("noecho") View.Set ("nobuttonbar") View.Set ("title:Stars 3D by Adam Bielinski") setscreen ("graphics:" + intstr (X_SCREEN) + ";" + intstr (Y_SCREEN)) View.Set ("position:centre,middle") View.Set ("offscreenonly")

Why do you have the x and y maximums hardcoded? It doesn't look as nice when you're at 1024x768, with the scrollbars distracting you and things being drawn where you can't see them. Why do you have 6 different screen-setting procedures? Why are you mixing "setscreen" with "View.Set"?

[richcash]

Yeah Windsurfer, that is AMAZING! But still, lol, it belongs in Turing Submissions as I'm sure it would be extremely difficult for Sniper_dude to implement that into his program.
Here's some basic rain I made using some OOP that should be easy to read and understand. It doesn't splash, and it doesn't look great, but it's easy to work with and you can try to put your own splash in later on.

code:

var camx, camy, camz : real camx := maxx / 2 camy := maxy / 2 camz := 0 class Drop     import camx, camy, camz     export init_, move, draw, delete     var x, y, z, zv, z2, screen_x, screen_y, screen_x2, screen_y2, zl : real     proc init_ (x_, y_, z_, zl_ : real)         x := x_         y := y_         z := z_         zv := 0.2         zl := zl_     end init_     proc move         z += zv         z2 := z + zl         screen_x := (x - camx) * 5 / (z - camz + 1e-3) + camx         screen_y := (y - camy) * 5 / (z - camz + 1e-3) + camy         screen_x2 := (x - camx) * 5 / (z2 - camz + 1e-3) + camx         screen_y2 := (y - camy) * 5 / (z2 - camz + 1e-3) + camy     end move     proc draw         Draw.Line (round (screen_x), round (screen_y), round (screen_x2), round (screen_y2), 11)     end draw     fcn delete () : boolean         result z > 9     end delete end Drop View.Set ("position:center;center,offscreenonly") var drops : flexible array 1 .. 0 of ^Drop var x, y, button : int colourback (7) cls loop     for n : 1 .. 3         new drops, upper (drops) + 1         new Drop, drops (upper (drops))         drops (upper (drops)) -> init_ (Rand.Int (0, maxx), Rand.Int (0, maxy), 0, 0.3)     end for     for i : 1 .. upper (drops)         exit when i > upper (drops)         if drops (i) -> delete () then             free drops (i)             drops (i) := drops (upper (drops))             new drops, upper (drops) - 1         else             drops (i) -> move             drops (i) -> draw         end if     end for     View.Update     delay (15)     cls end loop

[Ask me to comment it if necessary!]

[ericfourfour]

Here is my version of the rain system. Scroll down to the 3rd post to find it.

[SNIPERDUDE]

Thank you all for your replies, you got exactly what I needed and went beyond my expectations. The splash system is really cool and I never even expected that. Thank you once again. (now I can get back to other parts of my game) Yay!

PS: I will see if I can post my game when It's done