Attempt to detect sharp-turns.

2 files changed, 15 insertions, 5 deletions

diff --git a/MeshSketch.hs b/MeshSketch.hs
index ea8fbe6..7cda3fc 100644
--- a/MeshSketch.hs
+++ b/MeshSketch.hs
@@ -622,10 +622,15 @@ pushRing w st h k c = do
     g <- pushFront (fromList [h,k]) <$> readIORef (stRecentPts st)
     writeIORef (stRecentPts st) g
     with3 g $ \a b c -> do
-        let d = det $ fromRows [(b-c),(a-b)]
-        putStrLn $ "d = " ++ show d
+        let û = unit $ a-b
+            v̂ = unit $ b-c
+            δ = norm_1 $ (a-b)^2
+            d = det $ fromRows [û,v̂]
+            x = dot û v̂
+        putStrLn $ "(d,x) = " ++ show (d,x)
         updateBack (stRingBuffer st) $ \RingPoint{..} -> do
-            rpColor @<- if d<0 then blue else red
+            rpColor @<- if x < 0.3 || δ<0.5 then yellow
+                                            else if d<0 then blue else red
     pushBack (stRingBuffer st) $ \RingPoint{..} -> do
         rpPosition @<- d
         rpColor @<- c
diff --git a/hello_obj2.lc b/hello_obj2.lc
index 72a87ee..7b3d4a2 100644
--- a/hello_obj2.lc
+++ b/hello_obj2.lc
@@ -48,7 +48,12 @@ makeFrame (cubemap :: TextureCube)
   `overlay`
       points
     & mapPrimitives (\(p,c) -> let p' = coordmap cam $ point p
-                                in (p', point c))
+                                   w = p'%w
+                                   yellowish = normalize c `dot` V3 1 1 0
+                                   p2 = if yellowish >= 0.9*sqrt 2
+                                            then V4 p'%x p'%y 0.1 w
+                                            else V4 p'%x p'%y 0.11 w
+                                in (p2, point c))
 
     & renderPoints cam
 
@@ -61,7 +66,7 @@ renderPoints cam points =
       points
     & rasterizePrimitives (PointCtx (PointSize 5.0) 1.0 LowerLeft) ((Flat))
     & mapFragments (\((c)) -> ((c)))
-    & accumulateWith (DepthOp Always False, ColorOp NoBlending (V4 True True True True))
+    & accumulateWith (DepthOp Less True, ColorOp NoBlending (V4 True True True True))
 
 main :: Output
 main = renderFrame $