devkitPro

Posted: **Fri Jan 30, 2009 5:27 pm**

Hello everyone, I'm having a problem with array pointers in a function to manage my sprite during movements.. What I have is a function that checks which button's been pressed then adjusts the x and y and sets the frame to the object with the correct one (it's a walking character which has 3 frames animation for each direction -total 12 frames-). What I can't get right is the passing of parameters in the function. I don't want to have a messy code with a function inside the while loop or a global variable that keeps stored the current frame animation. I think it's a problem with pointer passing or something like that, this is the code:

Code: Select all

//function to read input and store sprite into curr (current sprite frame)
void handleInput(MySprite* curr,MySprite* spriteBank) {
     scanKeys();
    if (keysHeld() & KEY_UP) {
	if(curr->id==0)
	  curr = &spriteBank[2];
	else if(curr->id==2)
	  curr = &spriteBank[0];
	else
	  curr = &spriteBank[0];
	std::cout << "up pressed";
	posy-=step;
    } else if (keysHeld() & KEY_DOWN) {
	if(curr->id==6)
	  curr = &spriteBank[8];
	else if(curr->id==8)
	  curr = &spriteBank[6];
	else
	  curr = &spriteBank[6];
	std::cout << "down pressed";
	posy+=step;
    } else if (keysHeld() & KEY_LEFT) {
	if(curr->id==9)
	  curr = &spriteBank[11];
	else if(curr->id==11)
	  curr = &spriteBank[9];
	else
	  curr = &spriteBank[9];
	std::cout << "left pressed";
	posx-=step;
    } else if (keysHeld() & KEY_RIGHT) {
	if(curr->id==3)
	  curr = &spriteBank[5];
	else if(curr->id==5)
	  curr = &spriteBank[3];
	else
	  curr = &spriteBank[3];
	std::cout << "right pressed";
	posx+=step;
    } else {
	if((curr->id==0)||(curr->id==2))
	  curr = &spriteBank[1];
	else if((curr->id==3)||(curr->id==5))
	  curr = &spriteBank[4];
	else if((curr->id==6)||(curr->id==8))
	  curr = &spriteBank[7];
	else if((curr->id==9)||(curr->id==11))
	  curr = &spriteBank[10];
	std::cout << "stopped";
    }
}

//-----///
....

//inside while loop:
        swiWaitForVBlank();
	oamUpdate(&oamMain);
	oamClear(&oamMain,0,0);
	if(i%10==0){        //i is just a counter to slow down the frame changing speed
	handleInput(&curr,sprite);
	consoleClear();
	}
	i++;
}

the if check inside the handleInput function is just to check what frame the animation is at so it can put the other one.
Though when I try to run this code I can only see the spriteBank[0] frame....

MySprite curr is initialized as this:

Code: Select all

MySprite curr = sprite[0];

If I put the function inside the while loop (like, directly copy+paste it) or put curr as a global variable at the beginning of the program (outside the main function) everything works fine, but it's messy.

What am I doing wrong? can somebody please help?

thanks a lot

devkitPro

Problem with passing sprite pointers in function

Problem with passing sprite pointers in function