Use mutable vectors to store shape vertex counts

src/Dodge/Render.hs

@@ -45,8 +45,9 @@ doDrawing pdata w = do
     -- bind as much data into vbos as feasible at this point
     -- pictures setup
     layerCounts <- UMV.replicate (6*6) 0
+    shapeCounts <- UMV.replicate 3 (0 :: Int)
     -- attempt to do this poking in parallel
-    (nWalls,(nShapeVs,nIndices,nSilIndices)) <- MP.bindM3 (\ _ a b -> return (a,b))
+    nWalls <- MP.bindM3 (\ _ a _ -> return a)
         -- pictures poking
         ( pokeBindFoldableLayer shadV layerCounts $ worldPictures w )
         -- poke wall points and colors
@@ -55,8 +56,12 @@ doDrawing pdata w = do
             (_vboPtr $ _vaoVBO $ _shadVAO $ _shapeShader pdata)
             (_eboPtr $ _shapeEBO pdata)
             (_eboPtr $ _silhouetteEBO pdata)
+            shapeCounts
             $ worldShape w
         )
+    nShapeVs    <- UMV.read shapeCounts 0
+    nIndices    <- UMV.read shapeCounts 1
+    nSilIndices <- UMV.read shapeCounts 2
     -- bind wall points, silhouette data, surface geometry
     uncurry bindShaderBuffers $ unzip
         [ ( _wallTextureShader pdata, nWalls)