d3dx9: Allow passes argument to Begin() to be NULL.

dlls/d3dx9_36/effect.c

@@ -4202,7 +4202,7 @@ static HRESULT WINAPI ID3DXEffectImpl_Begin(ID3DXEffect *iface, UINT *passes, DW
 
     TRACE("iface %p, passes %p, flags %#x.\n", iface, passes, flags);
 
-    if (passes && technique)
+    if (technique)
     {
         if (flags & ~(D3DXFX_DONOTSAVESTATE | D3DXFX_DONOTSAVESAMPLERSTATE | D3DXFX_DONOTSAVESHADERSTATE))
             WARN("Invalid flags (%#x) specified.\n", flags);
@@ -4234,7 +4234,8 @@ static HRESULT WINAPI ID3DXEffectImpl_Begin(ID3DXEffect *iface, UINT *passes, DW
                 ERR("StateBlock Capture failed, hr %#x.\n", hr);
         }
 
-        *passes = technique->pass_count;
+        if (passes)
+            *passes = technique->pass_count;
         effect->started = TRUE;
         effect->begin_flags = flags;
 

dlls/d3dx9_36/tests/effect.c

@@ -3081,7 +3081,7 @@ static void test_effect_states(IDirect3DDevice9 *device)
         ok(!bval, "Got result %u, expected 0.\n", bval);
 
     hr = IDirect3DDevice9_SetTransform(device, D3DTS_WORLDMATRIX(1), &test_mat);
-    hr = effect->lpVtbl->Begin(effect, &npasses, 0);
+    hr = effect->lpVtbl->Begin(effect, NULL, 0);
     ok(hr == D3D_OK, "Got result %x, expected 0 (D3D_OK).\n", hr);
 
     hr = IDirect3DDevice9_GetTransform(device, D3DTS_WORLDMATRIX(1), &mat);