Subject: [stella] one last 16 bit compare question From: KirkIsrael@xxxxxxxxxxxxx Date: 9 Mar 2004 03:23:12 -0000 |
So I'm trying to wrap things up by Wednesday, a self-appointed deadline that should give Al sufficient enough time to put my ROMly dream into silicon. I added in a pretty nifty 3...2...1 countdown to start each game, as well as randomly launching the ball left or right, up or down (using the old "timer increments every frame, AND to get bit D0 and D1" trick) So except for considering some AI improvements, I have one more improvement to make... Al pointed out that when the ball goes flat, it definately doesn't look quite as cool. So I think along with a maximum vertical speed, I'd like to apply a minimum vertical speed. Though I'm not sure what the best way of doing that is. For the maximum, I punted, and just look at the integer part of the 16 bit (8 bit int, 8 bit 'fractional'): BALL_MAX_POS_SPEED = #1 BALL_MAX_NEG_SPEED = #-1 ;keep ball speed in range LDA slowBallYSpeed+1 CMP #BALL_MAX_POS_SPEED BMI BallSpeedLessThanMax LDA #BALL_MAX_POS_SPEED BallSpeedLessThanMax CMP #BALL_MAX_NEG_SPEED BPL BallSpeedGreaterThanMin LDA #BALL_MAX_NEG_SPEED BallSpeedGreaterThanMin STA slowBallYSpeed+1 Is that right, to keep the speed between 1 255/256 and -1 255/256 ? What would the code to keep the absolute value of the ball speed >= #%00100000 ? Should I do an AND $80 to see if it's negative, and then just do a specific comparison on the fractional byte? Thanks, and any last minute suggestions for JoustPong welcome... -- KirkIsrael@xxxxxxxxxxxxx http://kisrael.com "Sometimes your shallowness is so thorough, it's almost like depth."--Daria ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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