\documentclass[crop,border=5,tikz,convert={outext=,
  command=\unexpanded{pdf2svg \infile\space\outfile\%02d.svg
    all}},multi=false]{standalone}
\usetikzlibrary{math,calc,through,shapes,patterns,decorations.pathmorphing,intersections}
\usepackage{ifthen}

\newcommand{\markangle}[6][0.25]{
  \begin{scope}
    \clip (#2)--(#3)--(#4);
    \node (ANG) [draw, circle, minimum size=#5] at (#3){};
  \end{scope}
  \coordinate (E1) at (intersection 0 of ANG and #3--#2);
  \coordinate (E2) at (intersection 0 of ANG and #3--#4);
  %\draw[thick] (E1) to [bend right=50] (E2);
  \coordinate (EM) at ($ (E1)!0.5!(E2) $);
  \coordinate (EM) at ($ (EM)!#1!(#3) $);
  \node at (EM) {#6};
}

\begin{document}
\begin{tikzpicture}[>=latex,scale=1]
  \def\myt{30}
  \fill[white] (-6,0) rectangle (2,3);
  \clip(-6,-2)rectangle(2,3);
  \draw[thick, dashed] (0,-1.25) -- (0,2.95);
  \coordinate (A) at (180-\myt:6.5);
  \coordinate (B) at (\myt:3.5);
  \coordinate (O) at (0,0);
  \coordinate (L) at (0,3);
  \draw[blue, ultra thick] (A) -- (O) --  (B);
  \draw[blue, ultra thick,->] (A) -- ($ (A)!0.7!(O) $);
  \draw[blue, ultra thick,->] (O) -- ($ (O)!0.5!(B) $);
  \markangle{0,-1}{O}{3,0}{35}{$\cdot$}
  \draw[] (0,0)--(90-\myt:1.5);
  \draw[] (90+\myt:1.5)--(0,0);
  \foreach \a in {-7,-6.75,...,7}{
    \draw (180-\myt:\a) --+ (90-\myt:1.5);
    \draw (180-\myt:\a) --+ (-90-\myt:1.5);
    \draw (\myt:\a) --+ (90+\myt:1.5);
    \draw (\myt:\a)--+(-90+\myt:1.5);    
  }
  \fill[gray!90,opacity=0.90] (-6,-2) rectangle (2,0);
 
  \foreach \a in {0.25,0.5,...,7}{
    \tikzmath{
      \x=\a/cos(\myt);
      \myb=\a*tan(\myt);
      \o=1.4/sin(\myt);
      \r=\x/\o;
      \b=1-\x/\o;
      \g=0;
    }
    \definecolor{ccolor}{rgb}{\r,\g,\b}
    
    \ifthenelse{\lengthtest{\myb cm < 1.5 cm}}{
      \fill[ccolor] (-\x,0) circle (0.05);
      % \draw[dashed]($(\myt:\a)+(\myt-90:1.5)$)--(\x,0);
      % \draw[dashed]($(180-\myt:\a)+(270-\myt:1.5)$)--(-\x,0);
      \draw[semithick,dotted,ccolor] (-\x,0) circle (\a);
      \draw[ccolor] (-\x,0)--+(-\myt:\a);
      \draw[ccolor] (-\x,0)--+(\myt:\a);
    }{}
  }
  \draw[ultra thick,red] (-90+\myt:1.5)--(90+\myt:1.5);
\end{tikzpicture}

\end{document}