mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-12-11 08:23:19 +01:00
31 lines
1.2 KiB
Lua
31 lines
1.2 KiB
Lua
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local wea = worldeditadditions
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local Vector3 = wea.Vector3
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--- Converts a 2d heightmap into slope values in radians.
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-- Convert a radians to degrees by doing (radians*math.pi) / 180 for display,
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-- but it is STRONGLY recommended to keep all internal calculations in radians.
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-- @param heightmap table A ZERO indexed flat heightmap. See worldeditadditions.terrain.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 slope map, in the same form as the input heightmap. Each element of the array is a (floating-point) number representing the slope in that cell in radians.
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local function calculate_slopes(heightmap, heightmap_size)
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local normals = wea.terrain.calculate_normals(heightmap, heightmap_size)
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local slopes = { }
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local up = wea.Vector3.new(0, 1, 0) -- Z & Y are flipped
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for z = heightmap_size.z-1, 0, -1 do
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for x = heightmap_size.x-1, 0, -1 do
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local hi = z*heightmap_size.x + x
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-- Ref https://stackoverflow.com/a/16669463/1460422
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-- slopes[hi] = wea.Vector3.dot_product(normals[hi], up)
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slopes[hi] = math.acos(normals[hi].y)
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end
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end
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return slopes
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end
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return calculate_slopes
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