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Hey all,

I'm pretty new to the GDK, and I'm trying to make my player ship sprite rotate (trying to do an asteroids type game). I have a player update loop which I'm calling from the main update loop. Inside of the player loop I'm doing this:

if ( checkUp() )
{
dbMoveSprite(PLAYER_SPRITE,2.0f);
}

if ( checkRight() )
{
dbRotateSprite(PLAYER_SPRITE,2.0f);
}

if ( checkLeft() )
{
dbRotateSprite(PLAYER_SPRITE,-2.0f);
}

I'm running into two problems. The sprite only rotates once and then stops no matter how many times i press or if i hold the left or right keys. The other problem is that the sprite seems to be rotating off-center. I'd like to have the sprite rotate in the middle.

Can anyone help? (fyi, the move command is working fine.)

You'd probably be better off posting in the DGDK forums, but never mind.

First, take a look at the dbOffsetSprite function - this is used to specify the 'hotspot' of the sprite, which controls the rotation point and the positioning of the sprite relative to the coordinates you give it. Tinker around with it and you'll soon understand.

Next, the dbRotateSprite command sets the absolute rotation of the sprite, ie, it's not cumulative with earlier rotations. What you can do instead is use something like this to rotate:


The dbSpriteAngle gets the current angle of the sprite, then you add 2, then use dbWrapValue to ensure that the angle stays in the range of 0 to 360.

Thanks IanM, that did it. I also used dbOffsetSprite and it worked like a charm.