19
votes
Is something wrong with getType(object)?
The function detectCollision() returns NULL if there's no collision happened. You have to check whether your object is equal to NULL before you pass it to getType().
- 17.4k
12
votes
Accepted
getType() causing a seg fault when called on object as returned by detectcollision?
Pay close attention to what detectCollision() returns. What happens when there is no collision? (which will be most of the time). Are you handling that? It appears you are not, hence your segfault....
- 18.4k
11
votes
Accepted
Why does the ball glide along the paddle whenever it touches its sides?
What really causes this problem is that the ball hits one of the paddle's sides (or corners) and the bottom of the ball actually passes the top of the paddle.
let's call the distance between the ...
- 17.4k
8
votes
Accepted
Collision of ball with other objects
The Idea Behind Collision:
There's a function namely detectCollision() that's already written
for you and ready to use. This function, when it's called, checks
whether any of the sides of the ball ...
- 17.4k
8
votes
Accepted
Segmentation fault when trying to detect collisions in breakout
You may also have to make sure it's not null before you try to pass it into getType(). detectCollision will return null when there are no collisions.
- 352
6
votes
Bricks are not available to the detectCollision function
Your first assumption was not wrong. The bricks are not returned to the main function, so you need to find another way to refer to them while the game is running.
The bricks do definitely exist as ...
- 2,625
6
votes
Accepted
Segmentation Fault in Pset4 when detecting is brick is hit
You have to check whether object is equal to NULL before passing it to getType().
detectCollision() might return NULL in case there's no collision happened.
- 17.4k
6
votes
Accepted
Bricks aren't disappearing when hit with the ball
The function removeGWindow() receives a GWindow and a GObject not a GWindow and a string. You should be removing object when it's a GRect other than the paddle!
- 17.4k
6
votes
Why breakout does not restart after placing a new ball and clicking?
Instead of removing the ball and paddle from the window with removeGWindow, why not use another command (hint, hint) to change their positions back to where they began? Then you can allow normal play ...
- 171
5
votes
Accepted
Why Do I Get a Segmentation Fault When Trying to Move the Paddle?
You get a segmentation fault when you touch locations in memory that you shouldn't! Make sure your initPaddle() function doesn't return NULL and returns the paddle you created within it instead!
- 17.4k
5
votes
Accepted
Why is this code unable to bounce the ball
Converting the code to pseudo code might help to reveal the problem:
loop while lives > 0 and bricks > 0
set velocity to -0.5
move the ball in the y axis by the velocity
if the ...
- 2,625
5
votes
Accepted
Coloring the bricks in breakout
Yes. Usually there's a better approach to do something specially when you find yourself repeating code or checking every possible case manually to do something different in each situation.
I prefer ...
- 17.4k
4
votes
in pset4 only 1 row of bricks appear even with nested loop
This is a great question because it illustrates a very common mistake.
Here is an excerpt from your code:
for (int i = 0; i < ROWS; i++)
{
x = 2;
for (int j = 0; i < COLS; i++)
{
...
- 2,625
4
votes
Segmentation fault (core dumped) in the updateScoreboard function of pset4
Thankfully I found where I have done a mistake!
It's in the initScoreboard . I didn't add return scoreboard to be used in updateScoreboard because in the beginning of main there's GLabel label=...
4
votes
Accepted
How to use strcmp correctly in PSET4? (Using it cause my whole program to stop)
You need to add
if(object != NULL)
before your
if (object == paddle)
Your program stops because of "Segmentation Fault". The Detect-Collision function returns a NULL if no object is detected. You ...
- 428
4
votes
Accepted
why doesn't getColor work?
It returns an int that represents a color. See http://www.programmingsimplified.com/c/graphics.h/colors for more info. Also google getColor for more explanation.
You could use the actual color ...
- 64.2k
3
votes
Running breakout on Mac OS X
As such, the Stanford Portable Library is under a GNU license, which makes it legal for us (or in fact, me) to redistribute it to you, or anyone else, as stated by the license:
/**********************...
- 1,146
3
votes
Accepted
How to Update the Scoreboard in Breakout?
there is an updateScoreboard() function already implemented. You just need to call it with the parameters specified.
- 312
3
votes
Collision of ball with other objects
Here is a bit of psuedocode to help you define detectCollision:
If object is not equal to NULL then check if:
object == paddle, if it is, flip the y-velocity accordingly
else if, object == GRect (...
- 483
3
votes
Breakout slows down just before finishing the game
Just for the record, I had the same problem of breakout getting "laggy" after running (in the appliance) for a few seconds. Staff's implementation would run properly, so it wasn't strictly a hardware (...
- 1,140
3
votes
Accepted
What is the correct `wget` URL for breakout (pset 3) for spring 2015?
The zip file you linked contains folders for breakout and find, as specified in the problem set. There does not appear to be any fifteen content.
Note that find was moved to accompany breakout, as ...
- 882
3
votes
Accepted
Breakout - bounce off brick- why do I need to check for object == NULL?
If you're following the distribution code, you're likely to have a variable named paddle that stores an instance of your paddle. If the ball collides with the paddle, detectCollision returns an ...
- 17.4k
3
votes
Accepted
Segmentation fault testing for detectCollision returning NULL
I was having a similar problem when I moved from:
if (object == paddle)
to:
if (strcmp(getType(object), "GRect") == 0)
After reading your question, I realized I was probably not handling NULL ...
- 166
3
votes
Accepted
In Breakout the ball latches itself to paddle and bricks occasionally
It sounds like you've hit a known issue with this program. Is this what's happening? The ball hits the side of the paddle or a brick and it starts bouncing inside the paddle or brick until it emerges ...
- 64.2k
3
votes
Breakout: paddle no longer moves after ball movement inserted
look at your 2nd while loop that moves the ball, think about when your code will exit that and move on to the part of the code that moves the paddle
- 1,415
3
votes
Pset3 - Multiple nested if statements
Not sure what you mean by "many" if statements, but most people will use two nested for loops to create the bricks - an inner for loop to create each row and an outer for loop to do multiple rows. ...
- 64.2k
3
votes
Accepted
Breakout ScoreBoard
My guess is that the score is being displayed slightly low and slightly right of center. This is because setLocation() will place the object based on the upper left corner of the object, not the ...
- 64.2k
3
votes
Accepted
Breakout program freezes when i make it wait for click to start.
the problem is obviously that you're not updating event. that is, you're getting the next event only once. if it doesn't happen to be a mouse click, the value of event never changes and your program ...
- 17.4k
2
votes
Collision of ball with other objects
On the main routine, you have a call to a function that detect collisions.
The ball is the only moving object.
What you need to do is checking if the ball "touches" an object or the walls.
...
- 1,156
2
votes
initBricks as a 2d array of labelled bricks
You don't really need to have an array to store bricks. Once you create and add a brick to the window, it stays there until you remove it using the function named removeGWindow() from the SPL library ...
- 17.4k
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