From a4261598be7e3229a6280002eaced96d8cb3ced6 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Wed, 23 Jan 2019 19:54:21 -0800
Subject: Fixing GLSL sign function.

fixes #602
---
 source/slang/emit.cpp | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

(limited to 'source/slang/emit.cpp')

diff --git a/source/slang/emit.cpp b/source/slang/emit.cpp
index 0aebf6153..914aea7fd 100644
--- a/source/slang/emit.cpp
+++ b/source/slang/emit.cpp
@@ -3488,7 +3488,23 @@ struct EmitVisitor
             emit(".");
             operandIndex++;
         }
-
+        // fixing issue #602 for GLSL sign function: https://github.com/shader-slang/slang/issues/602
+        bool glslSignFix = ctx->shared->target == CodeGenTarget::GLSL && name == "sign";
+        if (glslSignFix)
+        {
+            if (auto vectorType = as<IRVectorType>(inst->getDataType()))
+            {
+                emit("ivec");
+                emit(as<IRConstant>(vectorType->getElementCount())->value.intVal);
+                emit("(");
+            }
+            else if (auto scalarType = as<IRBasicType>(inst->getDataType()))
+            {
+                emit("int(");
+            }
+            else
+                glslSignFix = false;
+        }
         emit(name);
         emit("(");
         bool first = true;
@@ -3499,7 +3515,8 @@ struct EmitVisitor
             first = false;
         }
         emit(")");
-
+        if (glslSignFix)
+            emit(")");
         maybeCloseParens(needClose);
     }
 
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