wined3d: Validate constant buffer alignment.

dlls/wined3d/buffer.c

@@ -1380,8 +1380,14 @@ static HRESULT buffer_init(struct wined3d_buffer *buffer, struct wined3d_device
 
     if (!size)
     {
-        WARN("Size 0 requested, returning WINED3DERR_INVALIDCALL.\n");
-        return WINED3DERR_INVALIDCALL;
+        WARN("Size 0 requested, returning E_INVALIDARG.\n");
+        return E_INVALIDARG;
+    }
+
+    if (bind_flags & WINED3D_BIND_CONSTANT_BUFFER && size & (WINED3D_CONSTANT_BUFFER_ALIGNMENT - 1))
+    {
+        WARN("Size %#x is not suitably aligned for constant buffers.\n", size);
+        return E_INVALIDARG;
     }
 
     if (data && !data->data)

dlls/wined3d/wined3d_private.h

@@ -2894,6 +2894,7 @@ void wined3d_resource_update_draw_binding(struct wined3d_resource *resource) DEC
 
 /* Tests show that the start address of resources is 32 byte aligned */
 #define RESOURCE_ALIGNMENT 16
+#define WINED3D_CONSTANT_BUFFER_ALIGNMENT 16
 
 struct gl_texture
 {