diff --git a/src/osx/carbon/graphics.cpp b/src/osx/carbon/graphics.cpp
index 4d1bd50a12..7362f96bcb 100644
--- a/src/osx/carbon/graphics.cpp
+++ b/src/osx/carbon/graphics.cpp
@@ -826,9 +826,9 @@ void wxMacCoreGraphicsBrushData::CalculateShadingValues (void *info, const CGFlo
         CGFloat fact = diff / range;
 
         out[0] = stops.comps[i - 1].red + (stops.comps[i].red - stops.comps[i - 1].red) * fact;
-        out[0] = stops.comps[i - 1].green + (stops.comps[i].green - stops.comps[i - 1].green) * fact;
-        out[0] = stops.comps[i - 1].blue + (stops.comps[i].blue - stops.comps[i - 1].blue) * fact;
-        out[0] = stops.comps[i - 1].alpha + (stops.comps[i].alpha - stops.comps[i - 1].alpha) * fact;
+        out[1] = stops.comps[i - 1].green + (stops.comps[i].green - stops.comps[i - 1].green) * fact;
+        out[2] = stops.comps[i - 1].blue + (stops.comps[i].blue - stops.comps[i - 1].blue) * fact;
+        out[3] = stops.comps[i - 1].alpha + (stops.comps[i].alpha - stops.comps[i - 1].alpha) * fact;
     }
 }