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67 lines
2.5 KiB
67 lines
2.5 KiB
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local math_abs, math_sign |
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= math.abs, math.sign |
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local minetest, vector, include |
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= minetest, vector, include |
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local rotate = include("rotate") |
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local utility = {} |
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-- Default selection boxes for a node that doesn't have one them explicitly. |
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local DEFAULT_SELECTION_BOX = { min = vector.new(-0.5, -0.5, -0.5), |
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max = vector.new( 0.5, 0.5, 0.5) } |
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-- Gets the active `selection_box` for the specified `node` which |
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-- has a `paramtype2` of `facedir`, based on its `param2` value. |
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local function get_node_active_selection_box(node) |
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local def = minetest.registered_nodes[node.name] |
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local box = def.selection_box and def.selection_box.fixed |
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-- No need to rotate the default selection box. |
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if not box then return DEFAULT_SELECTION_BOX end |
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-- If node definition specifies multiple selection boxes, just pick the first (for now). |
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if type(box[1]) == "table" then box = box[1] end |
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-- Transform the `{ x1, y1, z1, x2, y2, z2 }` box to a `{ min, max }` one. |
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box = { min = vector.new(box[1], box[2], box[3]), |
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max = vector.new(box[4], box[5], box[6]) } |
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-- Rotate the box to face `facedir`. |
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rotate.rotate_box_by_facedir(box, node.param2) |
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return box |
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end |
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-- Finds the closest edge of the node the player is looking at as |
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-- a vector pointing away from the center, and the distance to it. |
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local function find_closest_edge(node, pointed_thing) |
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-- For this math to work, we assume that selection box is centered. |
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local max = get_node_active_selection_box(node).max |
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-- Point relative to the collision box we're pointing at. |
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local point = pointed_thing.intersection_point - pointed_thing.under |
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-- Find the edge we're closest to. |
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local vec = vector.zero() |
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if math_abs(point.y / point.x) > max.x / max.y then |
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vec.y = math_sign(point.y) |
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if math_abs(point.z / point.x) > max.x / max.z |
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then vec.z = math_sign(point.z) |
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else vec.x = math_sign(point.x) |
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end |
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else |
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vec.x = math_sign(point.x) |
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if math_abs(point.z / point.y) > max.y / max.z |
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then vec.z = math_sign(point.z) |
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else vec.y = math_sign(point.y) |
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end |
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end |
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local d = 1 |
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local v = max - point:multiply(vec):apply(math_abs) |
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local EPSILON = tonumber("1.19e-07") |
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if math_abs(v.x) > EPSILON and v.x < d then d = v.x end |
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if math_abs(v.y) > EPSILON and v.y < d then d = v.y end |
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if math_abs(v.z) > EPSILON and v.z < d then d = v.z end |
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return vec, d |
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end |
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utility.find_closest_edge = find_closest_edge |
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return utility
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