From 3acea61ec05c54671e6e2b1254b35130a8b502c8 Mon Sep 17 00:00:00 2001
From: Csaba Hruska <csaba.hruska@gmail.com>
Date: Sat, 22 Sep 2018 12:13:15 +0200
Subject: support pipelines without color output

---
 lambdacube-compiler.cabal           |  2 +-
 src/LambdaCube/Compiler/CoreToIR.hs | 16 +++++++---------
 testdata/uniformparam02.out         |  2 +-
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/lambdacube-compiler.cabal b/lambdacube-compiler.cabal
index 6d47d950..8edcd5d6 100644
--- a/lambdacube-compiler.cabal
+++ b/lambdacube-compiler.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                lambdacube-compiler
-version:             0.6.1.0
+version:             0.6.2.0
 homepage:            http://lambdacube3d.com
 synopsis:            LambdaCube 3D is a DSL to program GPUs
 description:         LambdaCube 3D is a domain specific language and library that makes it
diff --git a/src/LambdaCube/Compiler/CoreToIR.hs b/src/LambdaCube/Compiler/CoreToIR.hs
index feb1d6e2..357702f5 100644
--- a/src/LambdaCube/Compiler/CoreToIR.hs
+++ b/src/LambdaCube/Compiler/CoreToIR.hs
@@ -39,6 +39,7 @@ import qualified LambdaCube.Compiler.Core as I
 import LambdaCube.Compiler.Infer (neutType', makeCaseFunPars')
 
 import Debug.Trace
+import Text.Printf
 
 import Data.Version
 import Paths_lambdacube_compiler (version)
@@ -112,20 +113,17 @@ getCommands backend e = case e of
 
             pUniforms' = snd <$> Map.filter ((\case UTexture2D{} -> False; _ -> True) . fst) pUniforms
 
-            imageSemantics   = getSemantics  e
-            imageTypes       = getImageInputTypes e
-            outImageType
-              = case imageTypes of
-                  []  -> error "Component-free pipelines are not supported."
-                  [x] -> x
-                  xs  -> flip fromMaybe (lookup IR.Color $ zip imageSemantics xs) $
-                         error "Multiple outputs, but no Color buffer?"
+            imageSemantics  = getSemantics  e
+            imageTypes      = getImageInputTypes e
+            outputValues    = case imageTypes of
+              []  -> error "Component-free pipelines are not supported."
+              xs  -> take 1 [IR.Parameter "f0" ty | (IR.Color, ty) <- zip imageSemantics xs] -- TODO: support multiple output
 
             prg = IR.Program
                 { IR.programUniforms    = pUniforms'
                 , IR.programStreams     = Map.fromList $ zip vertexInput $ map (uncurry IR.Parameter) input
                 , IR.programInTextures  = snd <$> Map.filter ((\case UUniform{} -> False; _ -> True) . fst) pUniforms
-                , IR.programOutput      = pure $ IR.Parameter "f0" outImageType
+                , IR.programOutput      = Vector.fromList outputValues
                 , IR.vertexShader       = show vertSrc
                 , IR.geometryShader     = mempty -- TODO
                 , IR.fragmentShader     = show fragSrc
diff --git a/testdata/uniformparam02.out b/testdata/uniformparam02.out
index 65c6f23c..dc824ba3 100644
--- a/testdata/uniformparam02.out
+++ b/testdata/uniformparam02.out
@@ -18,7 +18,7 @@ Pipeline
               fromList
                 [ ( "vi1" , Parameter { name = "position4" , ty = V4F } ) ]
           , programInTextures = fromList []
-          , programOutput = [ Parameter { name = "f0" , ty = V4F } ]
+          , programOutput = []
           , vertexShader =
               """
               #version 330 core
-- 
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