Fix/custom drawings (#18)

Reviewed-on: #18
Co-authored-by: dutchie031 <timrorije@gmail.com>

src/classes/util/Util.lua

@@ -297,6 +297,49 @@ do -- INIT UTIL
         return false
     end
 
+    ---@param points Array<Vec3>
+    ---@return Array<Vec3>
+    function UTIL.getConvexHull3d(points)
+        if #points == 0 then
+            return {}
+        end
+
+        ---comment
+        ---@param a Vec3
+        ---@param b Vec3
+        ---@param c Vec3
+        ---@return boolean
+        local function ccw(a, b, c)
+            return (b.z - a.z) * (c.x - a.x) > (b.x - a.x) * (c.z - a.z)
+        end
+
+        table.sort(points, function(left, right)
+            return left.z < right.z
+        end)
+
+        local hull = {}
+        -- lower hull
+        for _, point in pairs(points) do
+            while #hull >= 2 and not ccw(hull[#hull - 1], hull[#hull], point) do
+                table.remove(hull, #hull)
+            end
+            table.insert(hull, point)
+        end
+
+        -- upper hull
+        local t = #hull + 1
+        for i = #points, 1, -1 do
+            local point = points[i]
+            while #hull >= t and not ccw(hull[#hull - 1], hull[#hull], point) do
+                table.remove(hull, #hull)
+            end
+            table.insert(hull, point)
+        end
+        table.remove(hull, #hull)
+        return hull
+    end
+
+
     ---comment
     ---@param points Array<Vec2> points 
     ---@return Array<Vec2> hullPoints