Mercurial > gemma
diff pkg/mesh/util.go @ 4827:f4abfd0ee8ad remove-octree-debris
Renamed octree package to mesh as there is no octree any more.
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Tue, 05 Nov 2019 14:30:22 +0100 |
parents | pkg/octree/util.go@620038ade708 |
children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/pkg/mesh/util.go Tue Nov 05 14:30:22 2019 +0100 @@ -0,0 +1,37 @@ +// Copyright (C) 2018 Michael Fogleman +// +// Permission is hereby granted, free of charge, to any person obtaining +// a copy of this software and associated documentation files (the "Software"), +// to deal in the Software without restriction, including without limitation +// the rights to use, copy, modify, merge, publish, distribute, sublicense, +// and/or sell copies of the Software, and to permit persons to whom the +// Software is furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included +// in all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +package mesh + +import "math" + +var ( + eps = math.Nextafter(1, 2) - 1 + infinity = math.Inf(1) +) + +func pseudoAngle(dx, dy float64) float64 { + p := dx / (math.Abs(dx) + math.Abs(dy)) + if dy > 0 { + p = (3 - p) / 4 + } else { + p = (1 + p) / 4 + } + return math.Max(0, math.Min(1-eps, p)) +}