PureBasic Forums - English

Posted: **Tue Apr 07, 2009 1:57 am**

This is my Widescreen FOV (Field Of View) Calculator port
of my PHP original at: http://emsai.net/projects/widescreen/fovcalc/

PS! I know the results differ slightly... welcome to the world of floating point and it's various implementations.

There is also a simple FOV calculation commented out, a lot of the "calcs" out there probably uses that one, the one I use is based on the headache inducing math of Tan, ATan, PI, and degrees.

See Wikipedia for more: http://en.wikipedia.org/wiki/Field_of_v ... rocessing)

I also ported the oh so simple, but seemingly magic string parsers that supports the three most common ways to express aspect ratio plus resolution to aspect ratio conversion too.

Code: Select all

;FOV (Field Of View) Calculator v1.0 (C) Roger Hågensen, EmSai 2009 http://EmSai.net/
;
;This software is provided 'as-is', without any express or implied
;warranty.  In no event will the authors be held liable for any damages
;arising from the use of this software.
;
;Permission is granted to anyone to use this software for any purpose,
;including commercial applications, and to alter it and redistribute it
;freely, subject to the following restrictions:
;
;1. The origin of this software must not be misrepresented; you must not
;   claim that you wrote the original software. If you use this software
;   in a product, an acknowledgment in the product documentation would be
;   appreciated but is not required.
;2. Altered source versions must be plainly marked as such, and must not be
;   misrepresented as being the original software.
;3. This notice may not be removed or altered from any source distribution.

EnableExplicit

Procedure.d AspectStringToDouble(aspect$)
 Protected result.d,pos.i
 aspect$=LCase(aspect$)
 pos=FindString(aspect$,"x",1)
 If pos=0
  pos=FindString(aspect$,":",1)
 EndIf
 If pos
  result=ValD(Trim(Mid(aspect$,1,pos)))/ValD(Trim(Mid(aspect$,pos+1)))
 Else
  result=ValD(aspect$)
 EndIf
 ProcedureReturn result
EndProcedure

Procedure.d CalculateFOV(oldaspect.d,oldfov.d,newaspect.d)
 Protected result.d
 result=(ATan(Tan((oldfov*#PI)/360.0)*(newaspect/oldaspect))*360.0)/#PI
; result=oldfov*(newaspect/oldaspect) ;simple and crude, rough, not as accurate, but very fast.
 ProcedureReturn result
EndProcedure

Define oldaspect.d,oldfov.d,newaspect.d,newfov.d

Debug AspectStringToDouble("1680x1050")
Debug AspectStringToDouble("16:10")
Debug AspectStringToDouble("1.6")
Debug AspectStringToDouble("1.6:1")

Debug ""
Debug "1024x768 (aspect ratio), old FOV 90, new aspect is 1680x1050"
oldaspect=1024/768 ;AspectStringToDouble("1024x768")
oldfov=90.0
newaspect=1680/1050 ;AspectStringToDouble("1680x1050")
newfov=CalculateFOV(oldaspect,oldfov,newaspect)
Debug newfov

Posted: **Tue Apr 07, 2009 1:57 pm**

Thank you very much