A connect 4 clone for retrocomputers
by Marco Spedaletti (asimov@mclink.it)
This game is a "Connect Four" clone. It is a two-players, one-player and zero-player connection board game, in which the players take turns dropping colored tokens into a seven-column, six-row vertically suspended grid. The pieces fall straight down, occupying the lowest available space within the column. The objective of the game is to be the first to form a horizontal, vertical, or diagonal line of four of one's own tokens.
The game participates in the "Forza 4" Challenge of the RetroProgramming Italia - RP Italia group
The game allows you to select the type of player for each of the two colors, between computer and human, so there are 4 possible combinations:
- 2 players mode: RED (human) vs YELLOW (human);
- 1 player mode: RED (human) vs YELLOW (computer);
- 1 player mode: RED (computer) vs YELLOW (human);
- 0 player mode: RED (computer) vs YELLOW (computer).
By default the game always starts in 2 players mode. You can change this setting by pressing the following keys:
- pressing
1you choose RED player as human - pressing
2you choose RED player as computer - pressing
3you choose YELLOW player as human - pressing
4you choose YELLOW player as computer
Finally, pressing [SPACE] you will start the game.
RED color will start always as the first, while YELLOW color will be always the second. The gameplay example shows the first player starting by dropping one red token into the center column of an empty game board. The arrow always points to who gets the next move.
If the player is human, the keyboard will be enabled to wait for a keypress. By pressing a digit from 1 to 7 you will put a token on that particular column. If the column is not full, the token will move up to the lower free limit of the column. If the column is already full, the request will be ignored.
If the player is computer, it will choose automatically one of the (free) seven column to put the token on.
The two players then alternate turns dropping one of their tokens at a time into an unfilled column, until one of them achieves an horizontal, vertical or diagonal four in a row, and wins the game. If the board fills up before either player achieves four in a row, then the game is a draw.
This game has been programmed using ugBASIC, a BASIC dialect specialized in programs that are very efficient "by design" on various 8-bit platforms, without the need for "fine tuning" them and without compromises of other dev-kits.
To build the executable use the following command line (release v1.3.1 or better):
ugbc.c64 -o 4gravity.prg 4gravity.bas
Copyright 2021 Marco Spedaletti
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.