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65 lines
2.3 KiB
65 lines
2.3 KiB
1 year ago
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local math, ipairs
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= math, ipairs
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local minetest, vector
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= minetest, vector
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local rotate = {}
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-- Axis lookup table based on how Minetest's `facedir` operates.
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local AXIS_LOOKUP = {
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vector.new( 0, 1, 0), -- +Y
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vector.new( 0, 0, 1), -- +Z
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vector.new( 0, 0, -1), -- -Z
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vector.new( 1, 0, 0), -- +X
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vector.new(-1, 0, 0), -- -X
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vector.new( 0, -1, 0), -- -Y
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}
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-- Takes an axis vector and returns its index in the `AXIS_LOOKUP` table.
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-- Returns `nil` for any vector that is not a valid axis vector.
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local function axis_vector_to_index(vec)
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if vec.y == 1 then if vec.x == 0 and vec.z == 0 then return 1 end
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elseif vec.z == 1 then if vec.x == 0 and vec.y == 0 then return 2 end
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elseif vec.z == -1 then if vec.x == 0 and vec.y == 0 then return 3 end
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elseif vec.x == 1 then if vec.y == 0 and vec.z == 0 then return 4 end
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elseif vec.x == -1 then if vec.y == 0 and vec.z == 0 then return 5 end
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elseif vec.y == -1 then if vec.x == 0 and vec.z == 0 then return 6 end
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else return nil end
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end
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local FACEDIR_LOOKUP = {}
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for up_index, up in ipairs(AXIS_LOOKUP) do
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FACEDIR_LOOKUP[up_index] = {}
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for rot = 0, 3 do
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local facedir = (up_index - 1) * 4 + rot
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local back = minetest.facedir_to_dir(facedir)
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local back_index = axis_vector_to_index(back)
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FACEDIR_LOOKUP[up_index][back_index] = facedir
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end
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end
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-- Rotates `node` at the specified `pos` around `axis` by `degrees` counter-clockwise.
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local function rotate_node(pos, node, axis, degrees)
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if degrees % 90 ~= 0 then error("degrees must be divisible by 90") end
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if axis_vector_to_index(axis) == nil then error("axis must be an axis vector") end
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local def = minetest.registered_nodes[node.name]
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if def.paramtype2 ~= "facedir" then error("node's paramtype2 is not 'facedir'") end
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local up = AXIS_LOOKUP[1 + math.floor(node.param2 / 4)]
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local back = minetest.facedir_to_dir(node.param2)
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up = up :rotate_around_axis(axis, math.rad(degrees)):round()
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back = back:rotate_around_axis(axis, math.rad(degrees)):round()
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local up_index = axis_vector_to_index(up)
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local back_index = axis_vector_to_index(back)
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node.param2 = FACEDIR_LOOKUP[up_index][back_index]
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minetest.set_node(pos, node)
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end
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rotate.rotate_node = rotate_node
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return rotate
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