mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-06-03 05:03:02 +00:00
73 lines
2.9 KiB
Lua
73 lines
2.9 KiB
Lua
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--- Given a manip object and associates, generates a 2D x/z heightmap.
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-- Note that pos1 and pos2 should have already been pushed through
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-- worldedit.sort_pos(pos1, pos2) before passing them to this function.
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-- @param pos1 Vector Position 1 of the region to operate on
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-- @param pos2 Vector Position 2 of the region to operate on
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-- @param manip VoxelManip The VoxelManip object.
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-- @param area area The associated area object.
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-- @param data table The associated data object.
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-- @return table The ZERO-indexed heightmap data (as 1 single flat array).
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function worldeditadditions.make_heightmap(pos1, pos2, manip, area, data)
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-- z y x (in reverse for little-endian machines) is the preferred loop order, but that isn't really possible here
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local heightmap = {}
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local hi = 0
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local changes = { updated = 0, skipped_columns = 0 }
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for z = pos1.z, pos2.z, 1 do
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for x = pos1.x, pos2.x, 1 do
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local found_node = false
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-- Scan each column top to bottom
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for y = pos2.y+1, pos1.y, -1 do
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local i = area:index(x, y, z)
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if not worldeditadditions.is_airlike(data[i]) then
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-- It's the first non-airlike node in this column
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-- Start heightmap values from 1 (i.e. there's at least 1 node in the column)
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heightmap[hi] = (y - pos1.y) + 1
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found_node = true
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break
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end
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end
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if not found_node then heightmap[hi] = -1 end
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hi = hi + 1
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end
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end
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return heightmap
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end
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--- Calculates a normal map for the given heightmap.
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-- Caution: This method (like worldeditadditions.make_heightmap) works on
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-- X AND Z, and NOT x and y. This means that the resulting 3d normal vectors
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-- will have the z and y values swapped.
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-- @param heightmap table A ZERO indexed flat heightmap. See worldeditadditions.make_heightmap().
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-- @param heightmap_size int[] The size of the heightmap in the form [ z, x ]
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-- @return Vector[] The calculated normal map, in the same form as the input heightmap. Each element of the array is a 3D Vector (i.e. { x, y, z }) representing a normal.
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function worldeditadditions.calculate_normals(heightmap, heightmap_size)
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local result = {}
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for z = heightmap_size[0], 0, -1 do
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for x = heightmap_size[1], 0, -1 do
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-- Algorithm ref https://stackoverflow.com/a/13983431/1460422
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-- Also ref Vector.mjs, which I implemented myself (available upon request)
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local hi = z*heightmap_size[1] + x
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-- Default to this pixel's height
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local up = heightmap[hi]
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local down = heightmap[hi]
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local left = heightmap[hi]
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local right = heightmap[hi]
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if z - 1 > 0 then up = heightmap[(z-1)*heightmap_size[1] + x] end
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if z + 1 < heightmap_size[1] then down = heightmap[(z+1)*heightmap_size[1] + x] end
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if x - 1 > 0 then left = heightmap[z*heightmap_size[1] + (x-1)] end
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if x + 1 < heightmap_size[0] then right = heightmap[z*heightmap_size[1] + (x+1)] end
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result[hi] = worldeditadditions.vector.normalize({
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x = left - right,
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y = 2, -- Z & Y are flipped
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z = down - up
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})
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end
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end
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return result
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end
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