Zebediah Figura (@zfigura) commented about dlls/ddraw/device.c:
+ * We will fill it with following calls */ + wined3d_streaming_buffer_map(device->wined3d_device, &device->vertex_buffer, D3DMAXNUMVERTICES, stride, + &device->ddraw_device_buffer.vertex_buffer_pos, (void**) &device->ddraw_device_buffer.buffer_vertices); + wined3d_streaming_buffer_unmap(&device->vertex_buffer); + + wined3d_streaming_buffer_map(device->wined3d_device, &device->index_buffer, D3DMAXNUMVERTICES, sizeof(*device->ddraw_device_buffer.buffer_indices), + &device->ddraw_device_buffer.idx_buffer_pos, (void**) &device->ddraw_device_buffer.buffer_indices); + wined3d_streaming_buffer_unmap(&device->index_buffer); + } else if (fvf != device->ddraw_device_buffer.fvf) { + /* Not the same fvf as the buffered one. Cannot buffer more of those */ + TRACE_(ddraw_perf)("Buffering failed due to mismatched fvf %ld != buffer.fvf %ld \n", fvf, device->ddraw_device_buffer.fvf); + return WINED3DERR_NOTAVAILABLE; + } else if (primitive_type != device->ddraw_device_buffer.primitive_type) { + TRACE_(ddraw_perf)("Buffering failed due to mismatched primitive_type %d != buffer.primitive_type %d \n", primitive_type, device->ddraw_device_buffer.primitive_type); + return WINED3DERR_NOTAVAILABLE; + } Instead of returning false and retrying; I'd just flush here; that way you only need to call this function once, and it can't fail.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/2105#note_24899