basicbots overview and guide
This is the overview manual for basicbots programming game; with examples that will hopefully start you on your way.
The simulation
The Battlefield
The robots compete in a virtual battlefield that is 1000 units wide by 1000 units long. The upper left corner is 0,0 while the lower right corner is 1000,1000. There is a virtual wall that surrounds the battlefield. If a robot makes contact with this wall, it will take damage and its speed will be reduced to 0.
Cardinal directions
| | | | |:—-|:—:| —:| | 225 | 270 | 315 | | 180 | * | 000 | | 135 | 090 | 045 | | | | |
The Robot’s Hardware
The robot tank has three hardware systems.
-
A Scanner. The scanner can scan in any direction instantly but has an angular resolution from +-2 degrees to +- 10 degrees. Example: Scan 90 degrees with a width of 2 would return results that are between 88 - 92 degrees. A width of 10 would return results that are from 80 to 100 degrees.
-
A Cannon. The Cannon can fire a projectile in any direction but at a maximum range of 700 units. Any robot caught in the blast radius of 40 units. The farther from the center of the blast, the less damage a robot will take. Each robot can only have two projectiles in the air at any given time and it takes time to reload.
-
A Drive system. The drive system has two parameters. Angle and speed. The angle can be any angle from 0 to 360 degrees and the speed can be from 0 to 100%. The robots do require time to reach a given speed and require time to slow down. The robot can only negotiate turns when the speed is less than 50%. If the speed is above 50% the robot will slow down to 50% then turn and increase speed to the previous setting.
The Robot’s Status
The robot has access to:
- The X location. The current X position on the battlefield of the robot.
- The Y location. The current Y position on the battlefield of the robot.
- The Speed. The current speed of the robot.
- The Damage. The current amount of damage inflicted upon the robot. The robot can withstand up to 100 points of damage. Once a robot has reached 100 points, it has died and is removed from the battlefield. The amount of damage does not affect its performance.
That’s it. Three commands and four status sensors. With that, you can navigate the battlefield and annihilate the other robots!
The BASIC of basicbots
Keywords
| Command | Notes | |||||
|---|---|---|---|---|---|---|
| REM | Single line | A remark | ||||
| LET | Variable | = Value | Assign a value to a variable | |||
| GOTO | Line number | Transfer execution to the line number | ||||
| GOSUB | Line number | Transfer execution to the subroutine at line number | ||||
| RETURN | Transfers execution to the line following the GOSUB command | |||||
| IF | condition | THEN | statement | ELSE | statement | Excute the statement after THEN if condition is true if not then execute statement after ELSE |
| FOR | assignment | TO | value | STEP | value | Set the loop paramters |
| NEXT | variable | Return back to FOR changing the value of the assignment by the value in STEP | ||||
| DIM | variable | [size] | Create an array of the size specified. Note this array is 0 based unlike other BASICs. | |||
| DEF | FN | name | expresstion | Create a user defined function | ||
| FN | name | values | execute defined funtion name | |||
| SWAP | variable1 | variable2 | Exchange the values variable1 and variable2 | |||
| DATA | values, | List of values to be read | ||||
| READ | Reads the data stored by DATA. There is no reset ability at this time. | |||||
| AND | value1 | value2 | Bit AND of the value1 and value2. See truth table | |||
| OR | value1 | value2 | Bit OR of the value1 and value2. See truth table | |||
| XOR | value1 | value2 | Bit XOR or the value1 and value2. See truth table | |||
| LOCX | Returns the X Location of the robot. | |||||
| LOCY | Returns the Y Location of the robot. | |||||
| DAMAGE | Returns the current damage of the robot. | |||||
| SPEED | Returns the current speed of the robot. | |||||
| SCAN | angle | width | Scan for an enemy robot in the direction of angle with a width of +- width. | |||
| CANNON | angle | range | Fire the cannon at angle and range | |||
| DRIVE | angle | speed% | Engage the drive in the direction of angle with a speed of speed% |
Operators
| Operator | |
|---|---|
| = | Assign |
| * | Multiplication |
| - | Subtraction |
| % | Modulus |
| + | Addition |
| / | Division |
| ^ | Power |
| ( | Left Paren |
| ) | Right Paren |
| [ | Left index bracket |
| ] | Right index bracket |
| Operator | Returns non zero if true |
|---|---|
| > | Greater than |
| >= | Greater than or equal to |
| < | Less than |
| <= | Less than or equal to |
| <> | Not equal to |
Truth table
| VALUE | VALUE | RESULT | |
|---|---|---|---|
| AND | 0 | 0 | 0 |
| AND | 1 | 0 | 0 |
| AND | 0 | 1 | 0 |
| AND | 1 | 1 | 1 |
48 AND 12 = 0
0000000000110000 = 48
0000000000001100 = 12
0000000000000000 = 0
48 AND 16 = 16
0000000000110000 = 48
0000000000010000 = 16
0000000000010000 = 16
| VALUE | VALUE | RESULT | |
|---|---|---|---|
| OR | 0 | 0 | 0 |
| OR | 1 | 0 | 1 |
| OR | 0 | 1 | 1 |
| OR | 1 | 1 | 1 |
48 OR 12 = 60
0000000000110000 = 48
0000000000001100 = 12
0000000000111100 = 60
48 OR 16 = 48
0000000000110000 = 48
0000000000010000 = 16
0000000000110000 = 48
| VALUE | VALUE | RESULT | |
|---|---|---|---|
| XOR | 0 | 0 | 0 |
| XOR | 1 | 0 | 1 |
| XOR | 0 | 1 | 1 |
| XOR | 1 | 1 | 0 |
48 XOR 12 = 60
0000000000110000 = 48
0000000000001100 = 12
0000000000111100 = 60
48 XOR 16 = 32
0000000000110000 = 48
0000000000010000 = 16
0000000000100000 = 32
Whats next? Example code?
Some of the following code is tested on the original gobasic. It applies here as well.
Hello World
Lets start with the universal first program. helloworld.bas
10 PRINT "Hello World\n"
20 END
~/go/src/gobasic$ ./gobasic helloworld.bas
Hello World
~/go/src/gobasic$
If you followed allong congradulations, you just wrote your first basic program.
GOTO
Now lets introduce a GOTO. Remember GOTO transfers execacution to another line in the program.
10 PRINT "Hello World\n"
20 GOTO 10
Notice the lack of the END statement. Thats because this program never ends. After printing Hello World on line 10, the GOTO on line 20 jumps back to line 10 and it starts all over again.
Hello World
Hello World
Hello World
...
...
---
Hello World
Hello World
Hello World
That is a bit much. Just printing Hello World over and over, forever.
FOR TO NEXT STEP
Lets setup a FOR NEXT loop.
10 FOR I = 1 TO 5
20 PRINT "Hello World\n"
30 NEXT I
40 END
~/go/src/gobasic$ ./gobasic helloworld.bas
Hello World
Hello World
Hello World
Hello World
Hello World
~/go/src/gobasic$
The FOR on line 10 assignes the variable I the value of 1 and sets the limit to 5. This is the start of the loop.
The lines following the FOR will execute until the loop is finished.
The NEXT I causes the execution to transfer back to line 10 where I will be incremented by 1 and start the loop again. Once I equals 5 the NEXT statement will transfer exececution to the next line.
In this case will be the END and program will terminate.
Lets show that it is actuall incrementing. We will modified the PRINT state to include the variable I.
10 FOR I = 1 TO 5
20 PRINT "Hello World ",I,"\n"
30 NEXT I
40 END
~/go/src/gobasic$ ./gobasic helloworld.bas
Hello World 1
Hello World 2
Hello World 3
Hello World 4
Hello World 5
~/go/src/gobasic$
It is easy to see that the variable I is actuall incrementing by 1 on each pass of the loop. Next, we will check the STEP size.
10 FOR I = 1 TO 10 STEP 2
20 PRINT "Hello World ",I,"\n"
30 NEXT I
40 END
~/go/src/gobasic$ ./gobasic helloworld.bas
Hello World 1
Hello World 3
Hello World 5
Hello World 7
Hello World 9
~/go/src/gobasic$
You can see that the loop stepped by 2 on each pass of the loop.
Notice that the number 10 is never shown. Thats because I was larger than 10 so the execution went to the line following NEXT.
You can all step backwards if needed.
10 FOR I = 5 TO 1 STEP -1
20 PRINT "Hello World ",I,"\n"
30 NEXT I
40 END
~/go/src/gobasic$ ./gobasic helloworld.bas
Hello World 5
Hello World 4
Hello World 3
Hello World 2
Hello World 1
~/go/src/gobasic$
LET
LET sets the listed value to equal the number or statement
Simple assignment.
10 LET A = 1
20 PRINT A,"\n"
30 END
~/go/src/gobasic$ ./gobasic variables.bas
1
~/go/src/gobasic$
Variable A not has the value on 1. With LET more complete variable assignment can be done.
10 LET A = 1
15 LET B = 2
20 LET A = A + B
25 LET C = B - 1
20 PRINT A,B,C,"\n"
30 END
Hey, what was all that. Think about it before looking at the results below. Did it do what you thought it would?
~/go/src/gobasic$ ./gobasic variables.bas
3 2 1
~/go/src/gobasic$
Next we will use a math function in the assignment.
5 PRINT "Pythagorean Theorem\n"
10 LET A = 3
20 LET B = 4
30 LET C = SQR A + SQR B
40 LET C = C * C
40 PRINT A,B,C,"\n"
50 END
~/go/src/gobasic$ ./gobasic variables.bas
Pythagorean Theorem
3 4 5.000000
~/go/src/gobasic$