Avoid truncating in QSGMaterial::compare() implementations

The Qt 5.0 pattern of subtracting pointers and returning them is not
suitable (on 64-bit archs) since the return type is an int.

There is also QSGTexture::comparisonKey() now which is a qint64.

Just return -1 and 1 as appropriate.

Change-Id: Iaf3377b484a8c4b19b0960f1e8def05e4fa68ce7
Reviewed-by: Christian Strømme <christian.stromme@qt.io>

2 files changed, 7 insertions, 10 deletions

diff --git a/examples/quick/scenegraph/graph/noisynode.cpp b/examples/quick/scenegraph/graph/noisynode.cpp
index e85757d426..c39e775e98 100644
--- a/examples/quick/scenegraph/graph/noisynode.cpp
+++ b/examples/quick/scenegraph/graph/noisynode.cpp
@@ -107,10 +107,8 @@ public:
         if (!state.texture || !other->state.texture)
             return state.texture ? 1 : -1;
 
-        if (qint64 diff = state.texture->comparisonKey() - other->state.texture->comparisonKey())
-            return diff;
-
-        return 0;
+        const qint64 diff = state.texture->comparisonKey() - other->state.texture->comparisonKey();
+        return diff < 0 ? -1 : (diff > 0 ? 1 : 0);
     }
 
     struct {
diff --git a/examples/quick/scenegraph/twotextureproviders/xorblender.cpp b/examples/quick/scenegraph/twotextureproviders/xorblender.cpp
index 276625d908..9971f202a7 100644
--- a/examples/quick/scenegraph/twotextureproviders/xorblender.cpp
+++ b/examples/quick/scenegraph/twotextureproviders/xorblender.cpp
@@ -117,13 +117,12 @@ int XorBlendMaterial::compare(const QSGMaterial *o) const
     if (!state.texture2 || !other->state.texture2)
         return state.texture2 ? -1 : 1;
 
-    if (qint64 diff = state.texture1->comparisonKey() - other->state.texture1->comparisonKey())
-        return diff;
+    qint64 diff = state.texture1->comparisonKey() - other->state.texture1->comparisonKey();
+    if (diff != 0)
+        return diff < 0 ? -1 : 1;
 
-    if (qint64 diff = state.texture2->comparisonKey() - other->state.texture2->comparisonKey())
-        return diff;
-
-    return 0;
+    diff = state.texture2->comparisonKey() - other->state.texture2->comparisonKey();
+    return diff < 0 ? -1 : (diff > 0 ? 1 : 0);
 }
 
 XorBlendRhiShader::XorBlendRhiShader()