nurbs: NURBS

Simple NURBS library with support of NURBS, periodic NURBS, knot insertion-removal, NURBS split-joint

import Control.Lens
import Linear.NURBS
import Linear.V2
import Test.Hspec

-- | Simple NURBS of degree 3
test₁ ∷ NURBS V2 Double
test₁ = nurbs 3 [
  V2 0.0 0.0,
  V2 10.0 0.0,
  V2 10.0 10.0,
  V2 20.0 20.0,
  V2 0.0 20.0,
  V2 (-20.0) 0.0]

-- | Another NURBS of degree 3
test₂ ∷ NURBS V2 Double
test₂ = nurbs 3 [
  V2 (-20.0) 0.0,
  V2 (-20.0) (-20.0),
  V2 0.0 (-40.0),
  V2 20.0 20.0]

-- | Make test₁ periodic
testₒ ∷ NURBS V2 Double
testₒ = set periodic True test₁

main ∷ IO ()
main = hspec $ do
  describe "evaluate point" $ do
    it "should start from first control point" $
      (test₁ `eval` 0.0) ≃ (test₁ ^?! wpoints . _head . wpoint)
    it "should end at last control point" $
      (test₁ `eval` 1.0) ≃ (test₁ ^?! wpoints . _last . wpoint)
  describe "insert knot" $ do
    it "should not change nurbs curve" $
      insertKnots [(1, 0.1), (2, 0.3)] test₁ ≃ test₁
  describe "remove knots" $ do
    it "should not change nurbs curve" $
      removeKnots [(1, 0.1), (2, 0.3)] (insertKnots [(1, 0.1), (2, 0.3)] test₁) ≃ test₁
  describe "purge knots" $ do
    it "should not change nurbs curve" $
      purgeKnots (insertKnots [(1, 0.1), (2, 0.6)] test₁) ≃ test₁
  describe "split" $ do
    it "should work as cut" $
      snd (split 0.4 test₁) ≃ cut (Span 0.4 1.0) test₁
  describe "normalize" $ do
    it "should not affect curve" $
      cut (Span 0.2 0.8) test₁ ≃ normalizeKnot (cut (Span 0.2 0.8) test₁)
  describe "joint" $ do
    it "should joint cutted nurbs" $
      uncurry joint (split 0.3 test₁) ≃ Just test₁
    it "should cut jointed nurbs" $
      (cut (Span 0.0 1.0) <$> (test₁ ⊕ test₂)) ≃ Just test₁
    it "should cut jointed nurbs" $
      (cut (Span 1.0 2.0) <$> (test₁ ⊕ test₂)) ≃ Just test₂
  describe "periodic" $ do
    it "can be broken into simple nurbs" $
      breakLoop 0.0 testₒ ≃ testₒ
    it "can be broken in any place" $
      uncurry (flip (⊕)) (split 0.5 (breakLoop 0.0 testₒ)) ≃ Just (breakLoop 0.5 testₒ)

Modules

[Index]

Downloads

• nurbs-0.1.1.0.tar.gz [browse] (Cabal source package)
• Package description (revised from the package)

Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.

Maintainer's Corner

For package maintainers and hackage trustees

• edit package information