52 lines
1.2 KiB
Lua
52 lines
1.2 KiB
Lua
--- Mesh utilities.
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-- this is apart of the [LEEF-math](https://github.com/Luanti-Extended-Engine-Features/LEEF-math) module
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-- @module math.mesh
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local vec3 = require(modules .. "vec3")
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local mesh = {}
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-- vertices is an arbitrary list of vec3s
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function mesh.average(vertices)
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local out = vec3()
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for _, v in ipairs(vertices) do
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out = out + v
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end
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return out / #vertices
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end
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-- triangle[1] is a vec3
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-- triangle[2] is a vec3
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-- triangle[3] is a vec3
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function mesh.normal(triangle)
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local ba = triangle[2] - triangle[1]
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local ca = triangle[3] - triangle[1]
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return ba:cross(ca):normalize()
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end
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-- triangle[1] is a vec3
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-- triangle[2] is a vec3
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-- triangle[3] is a vec3
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function mesh.plane_from_triangle(triangle)
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return {
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origin = triangle[1],
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normal = mesh.normal(triangle)
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}
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end
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-- plane.origin is a vec3
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-- plane.normal is a vec3
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-- direction is a vec3
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function mesh.is_front_facing(plane, direction)
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return plane.normal:dot(direction) >= 0
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end
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-- point is a vec3
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-- plane.origin is a vec3
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-- plane.normal is a vec3
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-- plane.dot is a number
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function mesh.signed_distance(point, plane)
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return point:dot(plane.normal) - plane.normal:dot(plane.origin)
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end
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return mesh
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