Minetest-WorldEditAdditions/worldeditadditions/lib/ellipsoid.lua

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local wea_c = worldeditadditions_core
local Vector3 = wea_c.Vector3
---
-- @module worldeditadditions
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--- Fills an ellipsoidal area around the given position with the target node.
-- The resulting ellipsoid may optionally be hollow (in which case
-- nodes inside the ellipsoid are left untouched).
-- @param position Vector3 The centre position of the ellipsoid.
-- @param radius Vector3 The radius of the ellipsoid in all 3 dimensions.
-- @param target_node string The name of the node to use to fill the ellipsoid.
-- @param hollow bool Whether the ellipsoid should be hollow or not.
-- @returns number The number of nodes filled to create the (optionally hollow) ellipsoid. This number will be lower with hollow ellipsoids, since the internals of an ellipsoid aren't altered.
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function worldeditadditions.ellipsoid(position, radius, target_node, hollow)
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radius = Vector3.clone(radius)
-- position = { x, y, z }
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local hollow_inner_radius = radius - 1
-- Fetch the nodes in the specified area
-- OPTIMIZE: We should be able to calculate a more efficient box-area here
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local manip, area = worldedit.manip_helpers.init_radius(position, math.max(radius.x, radius.y, radius.z))
local data = manip:get_data()
local node_id = minetest.get_content_id(target_node)
local stride_z, stride_y = area.zstride, area.ystride
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local count = 0 -- The number of nodes replaced
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local idx_z_base = area:index(position.x - radius.x, position.y - radius.y, position.z - radius.z) -- initial z offset
for z = -radius.z, radius.z do
local idx_y_base = idx_z_base
for y = -radius.y, radius.y do
local i = idx_y_base
for x = -radius.x, radius.x do
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local here = Vector3.new(x, y, z)
-- If we're inside the ellipse, then fill it in
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local comp = here / radius
local ellipsoid_dist = Vector3.dot(comp, comp)
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if ellipsoid_dist <= 1 then
local place_ok = not hollow;
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if not place_ok then
-- It must be hollow! Do some additional calculations.
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local h_comp = here / hollow_inner_radius
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-- It's only ok to place it if it's outside our inner ellipse
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place_ok = Vector3.dot(h_comp, h_comp) >= 1
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end
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if place_ok then
data[i] = node_id
count = count + 1
end
end
i = i + 1
end
idx_y_base = idx_y_base + stride_y
end
idx_z_base = idx_z_base + stride_z
end
-- Save the modified nodes back to disk & return
worldedit.manip_helpers.finish(manip, data)
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return count
end