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labs:pong_part_2 [2019/11/20 09:50] jgoeders [Exercise #3 - Moving the Paddles and Collisions] |
labs:pong_part_2 [2019/12/03 16:26] (current) jgoeders [Exercise #1 - Drawing the objects] |
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| ==== State Machine ==== | ==== State Machine ==== | ||
| - | The diagram below provides the state machine that will control most of the Pong game. Rather than have separate states for drawing and erasing, the state machine is designed to use the same three states to draw the objects. Thus, the state machine will continuously repeat the state ordering (BALL->PADDLE_L->PADDLE_R->WAIT_TIMER->) to draw the objects and wait for some time, then (BALL->PADDLE_L->PADDLE_R->MOVE->) to erase the objects, and move them before repeating the same sequence again. | + | The diagram below provides the state machine that will control most of the Pong game. Rather than have separate states for drawing and erasing, the state machine is designed to use the same three states to draw the objects. Thus, the state machine will continuously repeat the state ordering (PADDLE_L->BALL->PADDLE_R->WAIT_TIMER->) to draw the objects and wait for some time, then (PADDLE_L->BALL->PADDLE_R->MOVE->) to erase the objects, and move them before repeating the same sequence again. |
| {{ :labs:lab_pong:pong_sm.png?600 |}} | {{ :labs:lab_pong:pong_sm.png?600 |}} | ||
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| - | 5. Create the above state machine with just the states needed to start the game and draw the objects: INIT, BALL, PADDLE_L and PADDLE_R. For this exercise you might want to create a DONE state that the state machine stays in once it is down drawing the right paddle. | + | 5. Create the above state machine with just the states needed to start the game and draw the objects: INIT, BALL, PADDLE_L and PADDLE_R. For this exercise you might want to create a DONE state that the state machine stays in once it is done drawing the right paddle. |
| 6. Implement the other components as follows: | 6. Implement the other components as follows: | ||
| - | * **Ball Location:** You should create a new ''always_ff'' block to manage the ball location. Create two registers, ''BallX'' and ''BallY'' that are reset to the center of the screen when ''initGame'' is true. This is sufficient for this exercise. | + | * **Ball Location:** You should create a new ''always_ff'' block to manage the ball location. Create two registers, ''ballX'' and ''ballY'' that are reset to the center of the screen when ''initGame'' is true. This is sufficient for this exercise. |
| * **Paddle Locations:** You should create a new ''always_ff'' block to manage the paddle locations. Create two registers, ''LPaddleY'' and ''RPaddleY'' that position the paddles halfway down the screen when ''initGame'' is true. This is sufficient for this exercise. | * **Paddle Locations:** You should create a new ''always_ff'' block to manage the paddle locations. Create two registers, ''LPaddleY'' and ''RPaddleY'' that position the paddles halfway down the screen when ''initGame'' is true. This is sufficient for this exercise. | ||
| * **Player Scores:** You should create a new ''always_ff'' block to manage the player scores. For this exercise, just assign the ''P1score'' and ''P2score'' registers to 0 when ''initGame'' is true. | * **Player Scores:** You should create a new ''always_ff'' block to manage the player scores. For this exercise, just assign the ''P1score'' and ''P2score'' registers to 0 when ''initGame'' is true. | ||
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| * **Ball Location:** Add more logic to your ball location component. When in the move state (''moveAndScore'' is high), update the ball location according to its direction. Consider the values of ''ballMovingRight'' and ''ballMovingDown'' and either add 1 or subtract 1 from ''ballX'' and ''ballY'' accordingly. | * **Ball Location:** Add more logic to your ball location component. When in the move state (''moveAndScore'' is high), update the ball location according to its direction. Consider the values of ''ballMovingRight'' and ''ballMovingDown'' and either add 1 or subtract 1 from ''ballX'' and ''ballY'' accordingly. | ||
| * **Ball Direction: ** You should create a new ''always_ff'' block to manage the ball directions (''ballMovingRight'' and ''ballMovingDown'' registers). On ''initGame'', you should reset these registers to values of your choice. When the ball hits a wall (check the ball location), you should update these registers appropriately. | * **Ball Direction: ** You should create a new ''always_ff'' block to manage the ball directions (''ballMovingRight'' and ''ballMovingDown'' registers). On ''initGame'', you should reset these registers to values of your choice. When the ball hits a wall (check the ball location), you should update these registers appropriately. | ||
| - | * **Erase Switch:** Create a flip-flop, ''erasing'' that is reset to 0 on ''initGame'' and flips its value if ''switchErase'' is high. | + | * **Erase Switch:** Create a flip-flop, ''erasing'' that is reset to 0 on ''initGame'' and flips its value if ''invertErase'' is high. |
| - | Use simulation to debug your design. You might consider making the timer delay small to make it faster to simulate your design. | + | |
| + | ** A note on debugging:** You will likely need to debug your design to get it working properly. The best way to do this is to set up a simulation tcl file. Consider how you can change your design to make it easier to simulate and debug. For example, you could make the timer delay small to make it faster to simulate, or change the values assigned to registers on ''initGame''. For example, you could initialize the ball close to a wall so that you don't need much simulation time in order to see if it bounced off of the wall correctly. | ||
