Getting slice number of regular polygon from coordinates











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For an n sided polygon divided up into n triangles, i want the triangle "index" from a coordinate inside the polygon



Example:



example



The coordinates at the green dot should give 2, the red dot should give 5 and the blue dot should give 3



Coordinate range is from 0 to diameter of the polygon



The polygon is not necessarily a 6 sided polygon






geometry polygons







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  • Do you have freedom of scaling, rotation and choosing the origin?
    – Moti
    Nov 11 at 16:27










  • only scaling/radius @Moti
    – nobbele
    Nov 16 at 18:34










  • What you mean by give? Being inside the numbered region?
    – Moti
    Nov 16 at 21:32















up vote
0
down vote

favorite












For an n sided polygon divided up into n triangles, i want the triangle "index" from a coordinate inside the polygon



Example:



example



The coordinates at the green dot should give 2, the red dot should give 5 and the blue dot should give 3



Coordinate range is from 0 to diameter of the polygon



The polygon is not necessarily a 6 sided polygon






geometry polygons







share|cite|improve this question
























  • Do you have freedom of scaling, rotation and choosing the origin?
    – Moti
    Nov 11 at 16:27










  • only scaling/radius @Moti
    – nobbele
    Nov 16 at 18:34










  • What you mean by give? Being inside the numbered region?
    – Moti
    Nov 16 at 21:32













up vote
0
down vote

favorite









up vote
0
down vote

favorite











For an n sided polygon divided up into n triangles, i want the triangle "index" from a coordinate inside the polygon



Example:



example



The coordinates at the green dot should give 2, the red dot should give 5 and the blue dot should give 3



Coordinate range is from 0 to diameter of the polygon



The polygon is not necessarily a 6 sided polygon






geometry polygons







share|cite|improve this question















For an n sided polygon divided up into n triangles, i want the triangle "index" from a coordinate inside the polygon



Example:



example



The coordinates at the green dot should give 2, the red dot should give 5 and the blue dot should give 3



Coordinate range is from 0 to diameter of the polygon



The polygon is not necessarily a 6 sided polygon






geometry polygons




geometry polygons






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 11 at 14:44

























asked Nov 11 at 13:46









nobbele

12




12












  • Do you have freedom of scaling, rotation and choosing the origin?
    – Moti
    Nov 11 at 16:27










  • only scaling/radius @Moti
    – nobbele
    Nov 16 at 18:34










  • What you mean by give? Being inside the numbered region?
    – Moti
    Nov 16 at 21:32


















  • Do you have freedom of scaling, rotation and choosing the origin?
    – Moti
    Nov 11 at 16:27










  • only scaling/radius @Moti
    – nobbele
    Nov 16 at 18:34










  • What you mean by give? Being inside the numbered region?
    – Moti
    Nov 16 at 21:32
















Do you have freedom of scaling, rotation and choosing the origin?
– Moti
Nov 11 at 16:27




Do you have freedom of scaling, rotation and choosing the origin?
– Moti
Nov 11 at 16:27












only scaling/radius @Moti
– nobbele
Nov 16 at 18:34




only scaling/radius @Moti
– nobbele
Nov 16 at 18:34












What you mean by give? Being inside the numbered region?
– Moti
Nov 16 at 21:32




What you mean by give? Being inside the numbered region?
– Moti
Nov 16 at 21:32










1 Answer
1






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up vote
0
down vote



accepted










Solved it using this(C# code but can probably be converted into math equation)



float arctan = Mathf.Atan(originRelativePos.x / originRelativePos.y);

float sectorDec = arctan / ((2 * Mathf.PI) / sectorCount);

float max = sectorCount / 4;



sectorDec = originRelativePos.x < 0 ? -sectorDec : sectorDec;

sectorDec = sectorDec > 0 ? sectorDec : max * 2 + sectorDec + 1;

sectorDec = originRelativePos.x < 0 ? sectorCount - sectorDec : sectorDec;



int sector = (int)sectorDec;


sector is the number of the sector, originRelativePos is position relative to the origin






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    1 Answer
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    active

    oldest

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    1 Answer
    1






    active

    oldest

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    active

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    active

    oldest

    votes








    up vote
    0
    down vote



    accepted










    Solved it using this(C# code but can probably be converted into math equation)



    float arctan = Mathf.Atan(originRelativePos.x / originRelativePos.y);
    
float sectorDec = arctan / ((2 * Mathf.PI) / sectorCount);
    
float max = sectorCount / 4;
    

    
sectorDec = originRelativePos.x < 0 ? -sectorDec : sectorDec;
    
sectorDec = sectorDec > 0 ? sectorDec : max * 2 + sectorDec + 1;
    
sectorDec = originRelativePos.x < 0 ? sectorCount - sectorDec : sectorDec;
    

    
int sector = (int)sectorDec;


    sector is the number of the sector, originRelativePos is position relative to the origin






    share|cite|improve this answer

























      up vote
      0
      down vote



      accepted










      Solved it using this(C# code but can probably be converted into math equation)



      float arctan = Mathf.Atan(originRelativePos.x / originRelativePos.y);
      
float sectorDec = arctan / ((2 * Mathf.PI) / sectorCount);
      
float max = sectorCount / 4;
      

      
sectorDec = originRelativePos.x < 0 ? -sectorDec : sectorDec;
      
sectorDec = sectorDec > 0 ? sectorDec : max * 2 + sectorDec + 1;
      
sectorDec = originRelativePos.x < 0 ? sectorCount - sectorDec : sectorDec;
      

      
int sector = (int)sectorDec;


      sector is the number of the sector, originRelativePos is position relative to the origin






      share|cite|improve this answer























        up vote
        0
        down vote



        accepted







        up vote
        0
        down vote



        accepted






        Solved it using this(C# code but can probably be converted into math equation)



        float arctan = Mathf.Atan(originRelativePos.x / originRelativePos.y);
        
float sectorDec = arctan / ((2 * Mathf.PI) / sectorCount);
        
float max = sectorCount / 4;
        

        
sectorDec = originRelativePos.x < 0 ? -sectorDec : sectorDec;
        
sectorDec = sectorDec > 0 ? sectorDec : max * 2 + sectorDec + 1;
        
sectorDec = originRelativePos.x < 0 ? sectorCount - sectorDec : sectorDec;
        

        
int sector = (int)sectorDec;


        sector is the number of the sector, originRelativePos is position relative to the origin






        share|cite|improve this answer












        Solved it using this(C# code but can probably be converted into math equation)



        float arctan = Mathf.Atan(originRelativePos.x / originRelativePos.y);
        
float sectorDec = arctan / ((2 * Mathf.PI) / sectorCount);
        
float max = sectorCount / 4;
        

        
sectorDec = originRelativePos.x < 0 ? -sectorDec : sectorDec;
        
sectorDec = sectorDec > 0 ? sectorDec : max * 2 + sectorDec + 1;
        
sectorDec = originRelativePos.x < 0 ? sectorCount - sectorDec : sectorDec;
        

        
int sector = (int)sectorDec;


        sector is the number of the sector, originRelativePos is position relative to the origin







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 16 at 22:44









        nobbele

        12




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