Gravity, Jump - GameCreators Forum

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Matt Bart

13

Years of Service

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Joined: 28th Nov 2010

Location:

Posted: 28th Nov 2010 15:29

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Hi guys, i know there is lot of it, but i dont know where is the problem in my program.I think, that \\\"sprite\\\" just didn\\\'t jump. I will be glad, if you can help me.

+ Code Snippet

bool JumpUp=false;
int xSpeed = 3;
int ySpeed = 10;
int xPos=400;
int yPos=400;
int MaxJump = 10;

+ Code Snippet

dbSprite(1,xPos,yPos,1);

+ Code Snippet

while ( LoopGDK ( ) )
	{
Fatman.Movement();//Just moving left and right...	
if(dbUpKey()==1 && !JumpUp){
JumpUp=true;
}
if(JumpUp){
yPos += ySpeed;
dbText(340, 240, \\\"JUMPING!\\\");
if(ySpeed == MaxJump){
ySpeed--;
}
if(ySpeed=0){
JumpUp=false;
}	
}
if ( dbEscapeKey ( ) )
break;
dbSync ( );
}
return;
}

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Mireben

15

Years of Service

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Joined: 5th Aug 2008

Location:

Posted: 28th Nov 2010 18:15 Edited at: 28th Nov 2010 18:20

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+ Code Snippet

if(ySpeed=0)

Equality check is DOUBLE equation sign. ==
With only one = you make ySpeed equal to zero so the jump stops immediately.

Also, for jumping up you should decrement yPos instead of incrementing it, since Y coordinates increase from the top of screen towards the bottom. And ySpeed should be decremented always, not only when it's equal to MaxJump, since in that case it will be decremented only once and it will never reach zero. Last, you should include a dbSprite instruction before dbSync, to display your sprite at the new coordinates, otherwise the sprite will never move.

Here is a modified code, summarizing all the above, does that work better?

+ Code Snippet

	Fatman.Movement();//Just moving left and right...	
	if (dbUpKey()==1 && !JumpUp) JumpUp=true;

	if (JumpUp) {
		yPos -= ySpeed;
		dbText(340, 240, \\\"JUMPING!\\\");
		ySpeed--;
		
		if (ySpeed==0) JumpUp=false;
	}

	dbSprite(1,xPos,yPos,1);
	if ( dbEscapeKey ( ) ) break;
	dbSync ( );

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Matt Bart

13

Years of Service

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Joined: 28th Nov 2010

Location:

Posted: 28th Nov 2010 18:41

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Just thanks.

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