diff --git a/dlls/d3d10/effect.c b/dlls/d3d10/effect.c
index 8c595736b51..220ec515cdd 100644
--- a/dlls/d3d10/effect.c
+++ b/dlls/d3d10/effect.c
@@ -2668,9 +2668,14 @@ static struct ID3D10EffectRasterizerVariable * STDMETHODCALLTYPE d3d10_effect_va
 static struct ID3D10EffectSamplerVariable * STDMETHODCALLTYPE d3d10_effect_variable_AsSampler(
         ID3D10EffectVariable *iface)
 {
-    FIXME("iface %p stub!\n", iface);
+    struct d3d10_effect_variable *This = (struct d3d10_effect_variable *)iface;
 
-    return NULL;
+    TRACE("iface %p\n", iface);
+
+    if (This->vtbl == (ID3D10EffectVariableVtbl *)&d3d10_effect_sampler_variable_vtbl)
+        return (ID3D10EffectSamplerVariable *)This;
+
+    return (ID3D10EffectSamplerVariable *)&null_sampler_variable;
 }
 
 static HRESULT STDMETHODCALLTYPE d3d10_effect_variable_SetRawValue(ID3D10EffectVariable *iface,