76 lines
2.9 KiB
Lua
76 lines
2.9 KiB
Lua
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-- Utility functions for dealing with 3D math and node rotations/facing directions
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-- "Facing" is the direction the top of the node points, i.e. the axis the node rotates around with a screwdriver.
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-- "Rotation" is the direction the "front" of the node points, i.e. the face that rotates with a screwdriver.
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-- The 6th texture in "tiles" of a facedir-type node is considered the "front" since that
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-- is the side that faces the player when placed.
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-- by Terumoc
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local THIS_VERSION = 2
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-- don't overwrite a later version if its already loaded
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if minetest.global_exists('util3d') and util3d.version >= THIS_VERSION then return end
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util3d = {}
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util3d.version = THIS_VERSION
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-- given a node pos plus another pos/offset, add them together
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function util3d.pos_plus(pos, offset)
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return {
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x=pos.x + offset.x,
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y=pos.y + offset.y,
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z=pos.z + offset.z,
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}
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end
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-- given a node pos plus offset, return the offset pos and node there
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function util3d.get_offset(pos, offset)
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pos = util3d.pos_plus(pos, offset)
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return pos, minetest.get_node_or_nil(pos)
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end
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-- given a facedir node's param2, return the FACING index
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function util3d.param2_to_facing(param2)
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return math.floor(param2 / 4)
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end
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-- given a facedir node's param2, return the ROTATION index
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function util3d.param2_to_rotation(param2)
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return param2 % 4
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end
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-- human-readable directions of facings
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util3d.FACING_DIRECTION = {
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[0]='up', [1]='north', [2]='south', [3]='east', [4]='west', [5]='down'
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}
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-- x/y/z offsets for each human-readable direction
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util3d.ADJACENT_OFFSETS = {
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east={x=1,y=0,z=0}, west={x=-1,y=0,z=0},
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up={x=0,y=1,z=0}, down={x=0,y=-1,z=0},
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north={x=0,y=0,z=1}, south={x=0,y=0,z=-1}
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}
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-- auto-generated constants for x/y/z offset in a facing index
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-- ex: FACING_OFFSETS[1]: 1 = facing north so returns offset of {x=0,y=0,z=1} (+1 node north)
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util3d.FACING_OFFSETS = {}
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for facing,dir in pairs(util3d.FACING_DIRECTION) do
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util3d.FACING_OFFSETS[facing] = util3d.ADJACENT_OFFSETS[dir]
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end
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-- relative x/y/z offset for rotations
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util3d.ROTATION_OFFSETS = {
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[0]={left={x=-1,y=0,z=0}, right={x=1,y=0,z=0}, front={x=0,y=0,z=-1}, back={x=0,y=0,z=1}, top=util3d.ADJACENT_OFFSETS.up, bottom=util3d.ADJACENT_OFFSETS.down},
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[1]={left={x=0,y=0,z=1}, right={x=0,y=0,z=-1}, front={x=-1,y=0,z=0}, back={x=1,y=0,z=0}, top=util3d.ADJACENT_OFFSETS.up, bottom=util3d.ADJACENT_OFFSETS.down},
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[2]={left={x=1,y=0,z=0}, right={x=-1,y=0,z=0}, front={x=0,y=0,z=1}, back={x=0,y=0,z=-1}, top=util3d.ADJACENT_OFFSETS.up, bottom=util3d.ADJACENT_OFFSETS.down},
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[3]={left={x=0,y=0,z=-1}, right={x=0,y=0,z=1}, front={x=1,y=0,z=0}, back={x=-1,y=0,z=0}, top=util3d.ADJACENT_OFFSETS.up, bottom=util3d.ADJACENT_OFFSETS.down},
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}
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util3d.RELATIVE_SIDES = { 'top', 'bottom', 'left', 'right', 'front', 'back' }
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function util3d.get_relative_pos(rot, pos, rel)
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if 'number'==type(rel) then rel = util3d.RELATIVE_SIDES[rel] end
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return util3d.pos_plus(pos, util3d.ROTATION_OFFSETS[rot][rel])
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end
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