[PATCH] ddraw: Pass correct box when mapping system memory vertex buffers.

[Józef Kucia]

This fixes a regression introduced by commit
5a8e430b96ab429a85f82f26ba9d2de4729954c2.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=46536
Signed-off-by: Józef Kucia 
---
 dlls/ddraw/device.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dlls/ddraw/device.c b/dlls/ddraw/device.c
index 4b58b75f3c2a..a9fb34a56bdc 100644
--- a/dlls/ddraw/device.c
+++ b/dlls/ddraw/device.c
@@ -4410,6 +4410,8 @@ static HRESULT d3d_device7_DrawIndexedPrimitiveVB(IDirect3DDevice7 *iface,
     {
         TRACE("Drawing from D3DVBCAPS_SYSTEMMEMORY vertex buffer, forwarding to DrawIndexedPrimitive().\n");
         wined3d_mutex_lock();
+        wined3d_box.left = start_vertex * stride;
+        wined3d_box.right = wined3d_box.left + vertex_count * stride;
         wined3d_resource = wined3d_buffer_get_resource(vb_impl->wined3d_buffer);
         if (FAILED(hr = wined3d_resource_map(wined3d_resource, 0, &wined3d_map_desc,
                 &wined3d_box, WINED3D_MAP_READ)))