add some functions to util

data/scripts/util.lua

@@ -0,0 +1,68 @@
+local Vector3 = require "types.vector3"
+
+local util = {}
+
+function util.printt(t)
+  if type(t) == 'table' then
+      local s = '{ '
+      for k,v in pairs(t) do
+        if type(k) ~= 'number' then k = '"'..k..'"' end
+        s = s .. '['..k..'] = ' .. util.printt(v) .. ','
+      end
+      return s .. '} '
+  else
+      return tostring(t)
+  end
+end
+
+function util.b2n(value)
+  return value and 1 or 0
+end
+
+---creates a list of vertices for a draw_quad call from a plane defined by position and normal
+---@param position Vector3
+---@param normal Vector3
+---@param size number
+---@return table
+function util.create_plane_quad(position, normal, size)
+  local axis = Vector3.UP:cross(normal)
+  local angle = math.acos(Vector3.UP:dot(normal))
+
+  local vlist = {
+    v0 = (Vector3(-0.5, 0, 0.5) * size):rotated(axis, angle) + position,
+    v1 = (Vector3(0.5, 0, 0.5) * size):rotated(axis, angle) + position,
+    v2 = (Vector3(0.5, 0, -0.5) * size):rotated(axis, angle) + position,
+    v3 = (Vector3(-0.5, 0, -0.5) * size):rotated(axis, angle) + position,
+  }
+
+  return vlist
+end
+
+---creates a shallow copy of the table t
+---@param t table
+---@return table
+function util.shallow_copy(t)
+  local t2 = {}
+  for k, v in pairs(t) do
+    t2[k] = v
+  end
+  return t2
+end
+
+---returns the intersection of tables t1 and t2, optionally overwriting t1's keys with t2's
+---@param t1 table
+---@param t2 table
+---@param overwrite boolean?
+---@return table
+function util.merge(t1, t2, overwrite)
+  local t3 = util.shallow_copy(t1)
+  overwrite = overwrite or true
+  for k, v in pairs(t2) do
+    if overwrite or not t3[k] then
+      t3[k] = v
+    end
+  end
+  return t3
+end
+
+return util