collision_circle()

Definition

INT collision_circle ( <INT processID|processTypeID> )

Checks if a process collided with the process calling collision_circle().

When a processTypeID is specified, there could be multiple fitting collisions. In this case, collision_circle() returns a processID on each subsequent call, until it returns 0. This can be reset by use of the frame; statement, and in such case, frame(0); can be handy.

The diference between collision_circle() and collision() is that collision_circle() only checks the distance with a circle in the edges of the processes, on the other side collision() check pixel by pixel between these processes. Consequently, collision_circle() is faster, but less accurate than collision().

See also collision() and collision_box().

Parameters

INT processID|processTypeID - The ProcessID of the process or the ProcessTypeID of the type of processes to be checked.

Returns

INT : The ID of the collided process.

0 - No collision
>0 - The processID of the process colliding with the current process

Example

Process SpaceShip( int file , int graph , int x , int y , int angle , int maxspeed , int maxturnspeed )
Private
    int speed;
    int collisionID;
    string text;
Begin
  write_string(0,0,0,0,&text);
    Loop
        // Handle movement
        speed+=key(_up)*(speed<maxspeed)-key(_down)*(speed>-maxspeed);
        angle+=(key(_left)-key(_right))*maxturnspeed;
        advance(speed);
        // Handle collision_box
        if( (collisionID = collision_circle(type main)))
            text = "collision with: " + collisionID;
        else
            text = "no collision";
        end
        frame;
    End
End

Process Main()
Private
    int map;
Begin

    // Create the graph for the ship
    map = map_new(20,20,8);
    map_clear(0,map,rgb(0,255,255));

    // Create the graph for the Main process
    graph = map_new(50,50,8);
    map_clear(0,graph,rgb(255,255,0));

    // Position the main process and create the ship
    x = y = z = 100;
    SpaceShip(0,map,100,100,0,20,5000);

    Repeat
        frame;
    Until(key(_ESC))

    let_me_alone();

End

Used in example: write_string(), key(), collision_circle(), map_new(), map_clear(), advance(), let_me_alone(), graph, type.

collision_box()collision()