Subject: Re: [stella] the B. Watson's problem... From: cybergoth@xxxxxxxx Date: Mon, 20 Aug 2001 11:12:37 +0200 (CEST) |
Hi B. Watson! Your source looks like this: > scan_loop: > sta WSYNC > sta HMOVE > ;XXX > lda pfdata0,y > sta PF0 > lda pfdata1,y > sta PF1 > lda pfdata2,y > sta PF2 > lda (spriteptr),y ; YYY > sta GRP0 ; YYY > lda (sprite0ptr),y ; YYY > sta GRP1 ; YYY > cpy evpos > bne skipenemy > lda #2 > bne drawenemy > skipenemy: > lda #0 > drawenemy: > sta ENAM1 > sta HMCLR > sta WSYNC > dey > bne scan_loop Some comments: - This isn't really a 2-line kernel, it's just a *forced* one. You're doing only one line and expand it via the second STA WSYNC. - To avoid your problem, you can do the playfield on the first line and the sprites on the second for example. - Having both sta HMOVE & sta HMCLR inside the kernel is senseless (in your case). Do that once outside the kernel. - Learn how to enable the missile via PHP, find the trick in the combat source for example. All your branching would be reduced to cpy evpos php if the stack is set/reset properly before and after the kernel - Learn how to display sprites properly via subtractions, there's no need to have tons of bytes zeroed out in the ROM. Find examples of this technique in the Stella archive under the 'Gunfight' topic. Thomas posted some detailed hints *how* it's done there. Find it utilised in (some :-)) Gunfight sources as well. HTH Greetings, Manuel ----------------------------------------------------------------------- Neu: Die Lern-, Spaß- und Erlebniswelt von Nexgo für Kinder von 4 bis 12 Jahren können Sie jetzt kostenlos testen: Klicken Sie einfach hier und ermöglichen Sie Ihrem Nachwuchs den Vorsprung in der Informationswelt von morgen. http://www.nexgo.de/family/kinder.php ----------------------------------------------------------------------- - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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