I was trying to plot a a couple of 3d vectors with a light cone in background. The code is a fusion of the following two old answers: Cut-off cone in TikZ and 2D and 3D vectors in Tikz. I was not able to get the vectors to show up for some reason. A working code is given below:
\documentclass{article}
\usepackage{pgfplots}
\usepackage{tikz-3dplot}
\pgfplotsset{compat=1.3}
\begin{document}
\tdplotsetmaincoords{60}{120}
\begin{figure}
\centering
\begin{tikzpicture}[scale=1.5, tdplot_main_coords, axis/.style={->,blue,thick},
vector/.style={-stealth,red,very thick},
vector guide/.style={dashed,red,thick}]
\begin{axis}[
axis lines=center,
axis on top,
xlabel={$x$}, ylabel={$y$}, zlabel={$t$},
domain=0:1,
y domain=0:2*pi,
xmin=-1.5, xmax=1.5,
ymin=-1.5, ymax=1.5, zmin=0.0,
every axis x label/.style={at={(rel axis cs:0,0.5,0)},anchor=south},
every axis y label/.style={at={(rel axis cs:0.5,0,0)},anchor=north},
every axis z label/.style={at={(rel axis cs:0.5,0.5,0.9)},anchor=west},
samples=30]
\addplot3 [surf, colormap/blackwhite, shader=flat] ({x*cos(deg(y))},{x*sin(deg(y))},{x});
%standard tikz coordinate definition using x, y, z coords
\coordinate (O) at (0,0,0);
%tikz-3dplot coordinate definition using x, y, z coords
\pgfmathsetmacro{\axone}{5}
\pgfmathsetmacro{\ayone}{3}
\pgfmathsetmacro{\azone}{4}
\pgfmathsetmacro{\axtwo}{3}
\pgfmathsetmacro{\aytwo}{5}
\pgfmathsetmacro{\aztwo}{0}
\coordinate (P1) at (\axone,\ayone,\azone);
\coordinate (P2) at (\axtwo,\aytwo,\aztwo);
\draw[vector] (O) -- (P1);
\draw[vector] (O) -- (P2);
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}
PS: I would like to use a transparent colored overlay to indicate the parallelogram bounded by the two vectors. So any code to achieve that will be greatly appreciated.
Edit:
Changed macro names to allowed ones after @marmot pointed out.

\pgfmathsetmacro{\ax1}{5}and so on by\pgfmathsetmacro{\axone}{5}etc. – Nov 18 '18 at 19:10