Programming :: Bird Eye View Game Shadow

I've been working on this console-based game (in c) in which the player walks around touches floating orbs which do things etc. And I want to make it so that an object on the map blocks the sight of the player, which is something I haven't tried until now. This is the part of the code which handles this sort of thing :

void uncover(int shadow)
{
int wp,
hp,
xp,
yp,
pp, // point placement
mp, // maximum pp value // (that's what she said)
lp; // light placement .....

This <works> but isn't very nice. What I would like to do is to change the third to last if statement, which is really more of a geometry problem, which could be frased as :
given points (x,y) , (plist[pp].x,plist[pp].y) and (wp,hp) create a conditional which tests weather or not point (wp,hp) is within the shadow cast by light-source (x,y) being blocked by an object at (plist[pp].x,plist[pp].y), [with some width, ~1]
but there isn't a geometry forum, and it's somewhat more related to programming.