wined3d: Fix IWineD3DPixelShader_GetFunction / IWineD3DVertexShader_GetFunction.

dlls/wined3d/pixelshader.c

@@ -127,8 +127,10 @@ static HRESULT  WINAPI IWineD3DPixelShaderImpl_GetFunction(IWineD3DPixelShader*
     return WINED3D_OK;
   }
   if (*pSizeOfData < This->baseShader.functionLength) {
-    *pSizeOfData = This->baseShader.functionLength;
-    return WINED3DERR_MOREDATA;
+    /* MSDN claims (for d3d8 at least) that if *pSizeOfData is smaller
+     * than the required size we should write the required size and
+     * return D3DERR_MOREDATA. That's not actually true. */
+    return WINED3DERR_INVALIDCALL;
   }
   if (NULL == This->baseShader.function) { /* no function defined */
     TRACE("(%p) : GetFunction no User Function defined using NULL to %p\n", This, pData);

dlls/wined3d/vertexshader.c

@@ -521,8 +521,10 @@ static HRESULT WINAPI IWineD3DVertexShaderImpl_GetFunction(IWineD3DVertexShader*
         return WINED3D_OK;
     }
     if (*pSizeOfData < This->baseShader.functionLength) {
-        *pSizeOfData = This->baseShader.functionLength;
-        return WINED3DERR_MOREDATA;
+        /* MSDN claims (for d3d8 at least) that if *pSizeOfData is smaller
+         * than the required size we should write the required size and
+         * return D3DERR_MOREDATA. That's not actually true. */
+        return WINED3DERR_INVALIDCALL;
     }
     if (NULL == This->baseShader.function) { /* no function defined */
         TRACE("(%p) : GetFunction no User Function defined using NULL to %p\n", This, pData);