Create can_see.lua

lua_scripts/can_see.lua

@@ -0,0 +1,32 @@
+--This is a basic raycast function.
+--It checks whether two points on a map can "see" each other based on the map data. It assumes flag 0 to be the collision layer.
+--It returns TRUE if they can see each other or FALSE if they can't. 
+function can_see(x1,y1,x2,y2,length)
+--x1 and y1 are the point of view,length is the max distance of the two points
+    local max_length=length or 1000
+    local xvec=0
+    local yvec=0
+    local len=0
+    local ret=true  
+    local tx=x1
+    local ty=y1
+    xvec=x2-x1
+    yvec=y2-y1
+    len=sqrt(xvec^2+yvec^2)
+    if len==0 or len>max_length then
+     ret=false
+    end
+    xvec=(xvec/len)
+    yvec=(yvec/len)
+    if ret then
+        for i=1,len do
+        tx+=xvec
+        ty+=yvec
+            if fget(mget(flr(tx/8),flr(ty/8)),0) then
+                ret=false
+                break
+            end
+        end
+    end
+    return ret
+end