Incursion

Incursion is a single-player 2D shooting game. The player controls a tank trying to reach the exit while there are walls and boulders that block the tank, and enemies that attack the tank. This game requires an Xbox controller. Use the left joystick to move the tank and the right joystick to rotate the turret. Reach the exit on the top right corner to win. This is another project built using my own engine, using C++ and OpenGL.

Apart from the normal version, I also made a "text version" of the game, replacing all entities with text.

Here is the control for the tank. As we can see when the tank rotates, it calls a function GetTurnedToward() to get the half-way direction of rotation. And the velocity is calculated based on current orientation and joystick magnitude, making sure that the tank rotates and moves at the same time.

Here is the function for tile-based 2D raycast. What it does is starting from the current position, try to figure out which tile it is going to hit next if the ray goes this way. Once it finds the next tile, it will find the exact position the ray touches the tile, then use this position as the new start position. Keep repeating this until the ray meets a solid tile or reach maximum distance.

Here is the map update and how the entity-vs-wall physics handled. All the entities have a disc collider and each tile has a square collider. So entity-vs-entity physics is just pushing two discs out of each other when intersected.

The way we handle entity-vs-wall is by checking all the eight tiles around the entity using the tile coordinates. If any of the tiles are solid as is intersecting with the entity, the entity will be pushed out of the square.