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Help with using arrow keys in SDL please

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Hello! Heres some code...
int KeyInfo(SDL_Event hi)
{
	int num = -5;

	if(hi.type == SDL_KEYDOWN){
		switch(hi.key.keysym.sym){
			case SDLK_UP:
				yvel=1;
				num=-1;
				break;
			case SDLK_DOWN:
				yvel=-1;
				num=-1;
				break;
			case SDLK_RIGHT:
				xvel=1;
				num=1;
				break;
			case SDLK_LEFT:
				xvel=-1;
				num=1;
				break;
			default:
				printf("hi");
				break;
		}
	}//	if(hi.type == SDL_KEYDOWN){

	if(hi.type == SDL_KEYUP){
		if(num)	{xvel = 0; printf("num=1, UP");}
		else if(!num)	{yvel = 0; printf("num=-1, DOWN");}
	}//	if(hi.type == SDL_KEYUP){

	return 1;
}

Thats the function. The xvel works but the yvel doesnt. When i press up and down "num=1, UP" is printed, the same as the left and right key. Its not recognizing when !num is true so its never setting yvel to 0. Is there something Im doing wrong?

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Why not:


int KeyInfo(SDL_Event hi)
{
if(hi.type == SDL_KEYDOWN){
switch(hi.key.keysym.sym){
case SDLK_UP:
yvel=1;
break;
case SDLK_DOWN:
yvel=-1;
break;
case SDLK_RIGHT:
xvel=1;
break;
case SDLK_LEFT:
xvel=-1;
break;
default:
printf("hi");
break;
}
}
else if(hi.type == SDL_KEYUP)
{
switch(hi.key.keysym.sym){
case SDLK_UP:
yvel=0;
break;
case SDLK_DOWN:
yvel=0;
break;
case SDLK_RIGHT:
xvel=0;
break;
case SDLK_LEFT:
xvel=0;
break;
default:
printf("hi");
break;
}
}// if(hi.type == SDL_KEYUP){

return 1;
}




AS for why it wasn't working before, i(!value) is like if( value != 0 ), not if( value > 0 ) which is what your code assumed.

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I changed it to
if(num==-1)
But that didnt work.


Quote:

AS for why it wasn't working before, i(!value) is like if( value != 0 ), not if( value > 0 ) which is what your code assumed.


I thought (num) meant true or above 0 while (!num) meant false or lower than 0 not just !=0.

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This topic is 4245 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

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