I don't understand C

struct tetro* newTetro(struct tetro* tetropointer,int r, int c, int ty){
tetropointer = (struct tetro*)malloc(sizeof(struct tetro));
tetropointer->row = r;
tetropointer->col = c;
tetropointer->type = ty;
switch(tetropointer->type){
case o:
tetropointer->shape = &blockshape;
break;
case i:
tetropointer->shape = &straightUp;
break;
default:
tetropointer->shape = &tshape;
}
return tetropointer;
};

void drawBlock(SDL_Renderer *r, SDL_Texture *t,int y,int x){
SDL_Rect destR;
destR.y = y;
destR.x = x;
destR.w = blockdimension; //size of blocks is 45 X 45
destR.h = blockdimension;
SDL_RenderCopy(r,t,NULL,&destR);
};

bool tetroDown(struct tetro * tetromino){
tetromino->potentialrow = tetromino->row+1;
tetromino->potentialcol = tetromino->col;
bool cantmove = false;
for(int i = 0; ipotentialcol] != 0){
cantmove = true;
break;
}
}
}
}
if(cantmove){
for(int i = 0; icol] = blockshape[i][j];
}
}
}
return true;
} else{
tetromino->row = tetromino->potentialrow;
tetromino->col = tetromino->potentialcol;
return false;

struct tetro* tetroptr = NULL;
tetroptr = newTetro(tetroptr,0,4,1);

while (appletMainLoop()){
currentMs = SDL_GetTicks();
if(currentMs - lastFell > fallms){
bool hitground = tetroDown(tetroptr);
lastFell = SDL_GetTicks();
if(hitground){
free(tetroptr);
tetroptr = newTetro(tetroptr,3,3,1);
Had to cut alot rendering and logic code to fit in a post but I think the relevant parts are these. Does anyone know why this crashes when a new tetromino is supposed to spawn? The first tetromino hits the bottom, can't move, and then the program crashes.

Attached: brainletpit.png (1416x1600, 606K)

Other urls found in this thread:

pastebin.com/kA4MsW52
pastebin.com/7Y9psSgz
twitter.com/NSFWRedditGif

Use a debugger. I can't be arsed to read your tiny program but it's probably an out-of-bounds access or null dereference, which are extremely simple mistakes which debuggers are good at catching.

It's nintendo switch homebrew, IDK how to use a debugger on one these unless I convert it to a linux program. Also it's not tiny it's just that I hit the 2000 character limit so had to take out the parts I think are irrelevant.

I'd just like to interject for a moment. What you're referring to as Linux, is in fact, GNU/Linux, or as I've recently taken to calling it, GNU plus Linux. Linux is not an operating system unto itself, but rather another free component of a fully functioning GNU system made useful by the GNU corelibs, shell utilities and vital system components comprising a full OS as defined by POSIX. Many computer users run a modified version of the GNU system every day, without realizing it. Through a peculiar turn of events, the version of GNU which is widely used today is often called "Linux", and many of its users are not aware that it is basically the GNU system, developed by the GNU Project. There really is a Linux, and these people are using it, but it is just a part of the system they use. Linux is the kernel: the program in the system that allocates the machine's resources to the other programs that you run. The kernel is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Linux is normally used in combination with the GNU operating system: the whole system is basically GNU with Linux added, or GNU/Linux. All the so-called "Linux" distributions are really distributions of GNU/Linux.

kys memester

You're right, I meant to say GNU/linux. The normies brainwashed me and made misspeak. Here's some more code I couldn't fit but I don't think it matters. hidScanInput();

// hidKeysDown returns information about which buttons have been
// just pressed in this frame compared to the previous one
u64 kDown = hidKeysDown(CONTROLLER_P1_AUTO);

if (kDown & KEY_PLUS)
break; // break in order to return to hbmenu

switch(kDown){
case KEY_LSTICK_RIGHT:
tetroptr->col++;
break;
case KEY_LSTICK_LEFT:
tetroptr->col--;
break;
}

SDL_RenderClear(renderer);
SDL_RenderCopy(renderer,bgtexture,NULL,NULL);
for(int i =0; i

wow that's some ugly coding

the newTetro() doesn't need to take the struct tetro* argument at all, it's used only as local variable would be. Also single letter global constants/enum names. Although don't see any bug there.

drawBlock() has semicolon at the end?

I don't see any access after free() though. I also don't see any bound checks in tetroDown() when it's already at the edge of field. My bet would be the block runs out of border and you write into some memory outside field.

Use pastebin, the code you posted is fucked. You are calling tetroDown from tetroDown.

>if(field[i+tetromino->potentialrow][j+tetromino->potentialcol] != 0)
This is out of bounds array access.

Good idea. pastebin.com/kA4MsW52
The name of the tetromino blocks are only 1 letter. Also I know that it doesn't need that arguement but I was trying weird stuff in hope it would stop crashing. If it was writing into some memory outside field would crash much faster I think?
Oh you think so? It only moves by one and there is a layer of blocks at the bottom so I don't think it should be out of bounds in this specific testing build and after that it should create a new block. but I do think I should check and try to prevent out of bounds checking there.