для любого режима, пишем в user32.delcs
.lib "user32.dll"
api_GetSystemMetrics% (nIndex%) : "GetSystemMetrics"
затем в игре :
Global GraphW = api_GetSystemMetrics(0)
Global GraphH = api_GetSystemMetrics(1)
Global GraphBits = api_GetSystemMetrics(2)
Graphics3d GraphW, GraphH, GraphBits