This plugin allows you to run GTA San Andreas, GTA Vice City and GTA 3 in windowed mode and with a working mouse cursor.
Update 07/10/2022:
Fixed "Alt" key opening the windowed menu (breaking gameplay).
Added an .ini file with the mod's internal parameters (for some reason it is not included in the official download). I disabled the menu by default (since it's only useful for developers).
The plugin will be very handy when writing mods or scripts.
Activation:
-Alt+Enter - change between frameless windowed and full screen modes; -Ctrl+Enter - enable or disable the window frame; -Ctrl+Alt - turn on the mouse cursor.
It is worth noting that in GTA San Andreas, unlike the other two games mentioned, the cursor is invisible. But he is still working.
Installation: extract the plugin to the Scripts or Modloader folder depending on the game.