runNT_ , gpu match example

packages/contrib/gpu/examples/match.hs

@@ -0,0 +1,20 @@
+import Vision.GUI
+import ImagProc
+import ImagProc.GPU.SIFT
+import Util.Misc(debug)
+
+getView m = clickKeep "click to set base view" (const id) (g m) Nothing
+
+main = do
+    prepare
+    match <- getMatchGPU
+    runNT_ camera $ sift grayscale >>> getView match
+
+
+g match ((x,psx),(s,pss)) = Draw [ Draw (rgb x)
+                                 , text (Point 0 0) (show (length psx, length matches))
+                                 , color red matches ]
+  where
+    matches' = match 0.7 0.8 psx pss
+    matches = map (\[a,b]-> (Segment (ipPosition (psx!! a)) (ipPosition(pss!! b)))) matches'
+

packages/contrib/gpu/examples/siftgpu.hs

@@ -4,7 +4,9 @@ import Vision.GUI
 import ImagProc
 import ImagProc.GPU.SIFT
 
-main = run $ sift grayscale >>> observe "SIFT GPU" sh
+main = do
+    prepare
+    runNT_ camera $ sift grayscale >>> observe "SIFT GPU" sh
 
 sh (x, feats) = Draw [ Draw (rgb x), color yellow feats ]
 

packages/gui/src/Vision/GUI/Arrow.hs

@@ -15,7 +15,8 @@ Arrow interface.
 -----------------------------------------------------------------------------
 
 module Vision.GUI.Arrow(
-    runITrans, runT_, runT, runS, ITrans(ITrans), transUI, arrL, (@@@), delay', arrIO
+    runITrans, runT_, runT, runS, ITrans(ITrans), transUI, arrL, (@@@), delay', arrIO,
+    runNT_,
 )where
 
 import Control.Concurrent   (forkIO)
@@ -28,6 +29,7 @@ import Control.Monad
 import Data.Either(lefts,rights)
 import System.IO.Unsafe(unsafeInterleaveIO)
 import Control.Concurrent
+import Graphics.UI.GLUT (mainLoopEvent)
 
 --------------------------------------------------------------------------------
 
@@ -140,6 +142,16 @@ runT_ gcam gt = runIt $ do
     g !_x = putStr ""
 
 
+runNT_ :: IO (IO a) -> ITrans a b -> IO ()
+-- ^ run process without fork, (needs explicit "prepare").
+-- This is currently required for certain GPU applications.
+runNT_ gcam gt = do
+    bs <- runS gcam gt
+    mapM_ g bs
+  where
+    g !_x = putStr "" >> mainLoopEvent
+
+
 runT :: IO (IO a) -> ITrans a b -> IO [b]
 -- ^ run a camera generator on a transformer, returning the results in a lazy list
 runT gcam gt = do