FreeBalistic - physical app to calculate ballistic curves

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Posts: 18
Joined: Feb 18, 2019 8:03

FreeBalistic - physical app to calculate ballistic curves

Postby peter-cat » Mar 06, 2019 9:09


I' ve been created application, that allows to input physical measures, calculate and show ballistic curve chart. Here is the link to the project:

...and some screenshoots:



I hope, that it will be useful for anyone of you.

The project in its current form is just a figment of what I would like to get, because there are some limitations that require the help of an expert in transforming physical patterns. That is what I would like to write about now.

According to what I wrote on the project website: "The aim of this project is to obtain a modification of the calculation that allows you to enter at least the angle of the projection and the strength of the wind."
Ultimately, there should be two additional fields in the program to introduce these quantities. I would like the application to only show a graph in one of the three considered planes, in a 2D view, and that the reading of the size and their analysis with the help of the legend image were intuitive. I need a formula for this purpose, which makes the result of the equation "z =" from the angle "alpha_xz" and includes the vector "Wx". Please, show the derivation, which allows you to develop the pattern for the placement of "Z =" in the "XZ" plane.

I am also asking for tips on how to consolidate patterns for rising and falling in one graph. Perhaps it is possible to transform both given patterns (climb and descent) so that a pattern is created that applies in this particular case, where the ballistic curve is considered in one dimension. The purpose of these applications is, as in most other programs of this type, the creation of a simple to analyze the 2D system, to calculate the height of the projectile after a specified time, possibly also calculating the distance traveled in a straight, horizontal line from the point of ejection. Unlike typical applications, however, the air resistance and wind force should also be taken into account. All this will be combined with a simple to read for the user drawing, presenting the size and 2D vectors used for calculations.

I am asking you, therefore, for the necessary diagrams and formulas to be available.
Posts: 2729
Joined: Sep 25, 2005 21:54

Re: FreeBalistic - physical app to calculate ballistic curves

Postby srvaldez » Mar 06, 2019 13:06

hello peter-cat :-)
your project look really good.
I would like to compile the program myself so that the menu would be in English, but there are missing bmp files, would you be so kind and add the necessary files for your project?
also, what IDE are you using?
Posts: 18
Joined: Feb 18, 2019 8:03

Re: FreeBalistic - physical app to calculate ballistic curves

Postby peter-cat » Mar 06, 2019 17:22

The BMP files you can download from Sourceforge project Website. There you can find screenshoots atached to project. One of them are Your missing files, just open it in new tab and save as BMP via your net browser.
I am using FBEdit. In the Website on Sourceforge there is the project file of this Editor, *.FBP.
Posts: 6949
Joined: Jan 10, 2006 20:30
Location: Scotland

Re: FreeBalistic - physical app to calculate ballistic curves

Postby dodicat » Mar 07, 2019 1:50

Interesting subject.
for fun
Drag is proportional to velocity, and a wind factor.

Code: Select all

Dim  As Integer xres,yres
Screen 20,32,,64
Screeninfo xres,yres
Dim Shared As Any Ptr i:i=Imagecreate(xres,yres,0)

Type v2
    As Single x,y
End Type

Type screendata
    As Integer w,h,depth,bpp,pitch
    As Any Pointer row
    As Ulong Pointer pixel32
End Type

Dim Shared As screendata ThisScreen,thisimage
With ThisScreen
    Screeninfo .w,.h,.depth,.bpp,.pitch
End With
With thisimage
    Imageinfo i,.w,.h,.bpp,.pitch,.row
End With

Const k=1   
Const g=9.81  'gravity
Const m=5     'mass
Const pi=4*Atn(1)
Dim Shared As Integer mx,my,btn

#define range(f,l) Int(Rnd*((l+1)-(f))+(f))
#define map(a,b,x,c,d)  ((d)-(c))*((x)-(a))/((b)-(a))+(c)
#define incircle(cx,cy,radius,x,y) (cx-x)*(cx-x) +(cy-y)*(cy-y)<= radius*radius
#define inbox mx>20 andalso mx<400 andalso my>300 andalso my<340

Sub bline(sd As screendata,x1 As Integer,y1 As Integer,x2 As Integer,y2 As Integer,col As Ulong)
    #define ppset32(_x,_y,colour) *Cptr(Ulong Ptr,sd.row+ (_y)*sd.pitch+ (_x) Shl 2)  =(colour)
    #define onscreen ((x1+x)>=0) And ((x1+x)<(sd.w-1)) And ((y1+y)>=0) And ((y1+y)<(sd.h-1))
    Var dx=Abs(x2-x1),dy=Abs(y2-y1),sx=Sgn(x2-x1),sy=Sgn(y2-y1)
    Dim As Integer e
    If dx<dy Then  e=dx\2 Else e=dy\2
        For x As Integer=0 To 1
            For y As Integer=0 To 1
                If onscreen Then
                End If
            Next y
        Next x
        If x1 = x2 Then If y1 = y2 Then Exit Do
        If dx > dy Then
            x1 += sx : e -= dy : If e < 0 Then e += dx : y1 += sy
            y1 += sy : e -= dx : If e < 0 Then e += dy : x1 += sx
        End If
End Sub
'Bressenham line thickened
Sub thickline(sd As screendata,_
    x1 As Long,_
    y1 As Long,_
    x2 As Long,_
    y2 As Long,_
    thickness As Single,_
    colour As Ulong)
    Var h=Sqr((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))
    Var s=(y1-y2)/h
    Var c=(x2-x1)/h
    For yp As Double=-thickness/2 To thickness/2 'step 2
    Next yp
End Sub

Sub drawline(s As screendata,x As Long,y As Long,angle As Single,length As Long,col As Ulong)
    Var x2=x+length*Cos(angle)
    Var y2=y-length*Sin(angle)
End Sub

Sub clearimage()
    Line i,(0,0)-(1023,767),Rgba(0,0,0,220),bf
End Sub

Function Regulate(Byval MyFps As Long,Byref fps As Long=60) As Long
    Static As Double timervalue,lastsleeptime,t3,frames
    If (Timer-t3)>=1 Then t3=Timer:fps=frames:frames=0
    Var sleeptime=lastsleeptime+((1/myfps)-Timer+timervalue)*1000
    If sleeptime<1 Then sleeptime=1
    Return sleeptime
End Function

Sub fire(startpos As v2,theta As Single,v As Single)
    #macro show_wind(d)
    Draw String(500,20),"Wind " & Abs(w)
    If d<0 Then
        Draw String(500,60),"<------"
        Draw String(500,60),"------>"
    End If
    Dim As Integer xres,yres,w=range(-10,10)
    Screeninfo xres,yres
    Dim As v2 position,lastposition
    Dim As Single t
        Locate 2,2
        Print "Speed "; 100*Sqr((position.x-lastposition.x)^2+(position.y-lastposition.y)^2)
        Sleep regulate(60)
        If incircle(1000,20,10,position.x,position.y) Then  Draw String i,(500,500),"HIT"
    Loop Until position.y<0
End Sub

Sub show(p As Integer,theta As Long,cx As Long,cy As Long)
    Draw String(135,145),"Fire",Rgb(200,0,0)
    Draw String(50,280),"Powder = " &p
    Draw String(400,320),"<--- Adjust Powder"
    Draw String(20,350),"100                                          300"
    Draw String(100,740),"<------  Adjust elevation"
    Draw String(20,600),"Elevation = "&theta
End Sub

Dim As String key

Dim As Integer cx=200,cy=320,powder=200,theta=40
Dim As v2 startpos
Dim As Single a=theta*pi/180
    Getmouse mx,my,,btn
    If btn=1 And inbox Then
        If cx<40 Then cx=40
        If cx>380 Then cx=380
    End If
    If incircle(150,150,25,mx,my) And btn Then
    End If
    If incircle(0,768,100,mx,my) And btn=1 Then
    End If
Loop Until key=Chr(27)
If i Then Imagedestroy i

Posts: 18
Joined: Feb 18, 2019 8:03

Re: FreeBalistic - physical app to calculate ballistic curves

Postby peter-cat » Mar 14, 2019 12:17


It's time for first update of my app! The files of newer FreeBalistic version are available on:
Feel invited to download this update!

Screen of currently released version:


Have Fun, this time with english GUI !
Lachie Dazdarian
Posts: 2338
Joined: May 31, 2005 9:59
Location: Croatia

Re: FreeBalistic - physical app to calculate ballistic curves

Postby Lachie Dazdarian » Mar 26, 2019 0:27

Really cool stuff. Something I wanted to do for a while (learn/refresh physics by producing physics related toys/educational programs).

Realtime simulation planned?
Posts: 18
Joined: Feb 18, 2019 8:03

Re: FreeBalistic - physical app to calculate ballistic curves

Postby peter-cat » Apr 01, 2019 6:11

The real time simulation is not plannet yet, but I was thinking about it. Maybe some animation of moving bullet will be added. But first I would like to fix the problem of the tight scope of values on the chart. It should be more flexible and work like Excel, that can automatically make the scales for axis in charts. I was looking for some freebasic charts library and it seems like it is possible to use it in this app. I'll do it when I get some free time, maybe then with some advanced graphical simulations :)
Posts: 3826
Joined: Jun 02, 2013 9:27
Location: Switzerland

Re: FreeBalistic - physical app to calculate ballistic curves

Postby MrSwiss » Apr 01, 2019 13:36

As you've noted yourself, it's currently having a to much limited scope.
(guns can fire 'downhill' too)

I'm an old armourer of the: Oerlikon_GDF (twin AA auto-cannon, 35 mm NATO),
which have a barrel movement angle from: below 0° to more than 90° (straight up).
This would require a change in the currently pre-set min./max. input values ...
(a split into height of cannon itself (barrel pivot point) and added/subtracted barrel
end's distance (from pivot), derived from lenght/angle of barrel+weapon)

There is yet another part to be taken into consideration: (but nice, for animation!)
The War-Amunition (grenades) have a 'self destruct' mechanism, set at 4000 m (of flight).
The latest Ammo, called AHEAD, is even a more complex beast, to deal with ...
Posts: 18
Joined: Feb 18, 2019 8:03

Re: FreeBalistic - physical app to calculate ballistic curves

Postby peter-cat » Sep 12, 2019 8:16

Acording to proposals of MrSwiss: Hmm, interesting idea...

As we have some good chart library, we can finally modify the way of displaying the plots, and solve problem of tight scopes on the chart.
It will require to implement the chart library and change the code responsible for drawing charts, to adapt it in this case. The library is available here (Chart.bas file): ... /files/V3/

Second thing, probably most hard, is to change loops in calculating functions to give them a new prepared data in dynamic memory structures. I mean wider amount of loop steps to calcullate.

This program bases only on the two physical patterns to calculate in the different ways the nine measures. It operates on loops to achieve this effect, what causes a lot of operations to make by processor. Currently, the small scopes prevents from the high usage of processor. But if we want to use wider scopes, then it could cause the problems with weak performance. So here we need the help of physician, to transform the pattern for use in each of nine function. If you are interested in patterns, then here is the link to e-book, that I' ve been using (I took the patterns from it): ... rowych.pdf

It's in Polish language, but I think, that Google Translate can manage... ;) The most important things starts at page 101.
Good luck :)
I have recently too small time to back to this project, so don't hesitate, if you want help.
Posts: 556
Joined: Mar 10, 2007 15:44
Location: Ohio, USA

Re: FreeBalistic - physical app to calculate ballistic curves

Postby bcohio2001 » Sep 17, 2019 23:17

Changes sent to your e-mail.

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