Search found 487 matches

by Miquel
Wed Aug 24, 2016 5:43 pm
Forum: SGDK
Topic: Line scrolling
Replies: 9
Views: 2449

Re: Raster perspective for background layer.

My best guess is this is doing using horizontal scroll per line. Very much like full plane scroll, you apply to every line the same value except the ones which are doing this effect which have higher rations of scroll as they are close to the viewers eye.

Perhaps someone can tell more details.
by Miquel
Tue Aug 23, 2016 2:02 pm
Forum: Video Display Processor
Topic: VDP access from Z80 questions
Replies: 16
Views: 5314

Re: VDP access from Z80 questions

I guess you're not using sgdk (which add overload for hint handler). No, I'm not using SGDK, aldo at the beginning, when I didn't know very much about MD internals I follow up it very close. You said your hint is already as fast as possible, do that mean the instructions sequence is similar to: mov...
by Miquel
Mon Aug 22, 2016 9:48 pm
Forum: Video Display Processor
Topic: VDP access from Z80 questions
Replies: 16
Views: 5314

Re: VDP access from Z80 questions

You can do axelay scrolling using hint, just use a very fast hint callback. You can prepare all the table and setup VDP control port during vint so you just need to write a single (or 2 for 2 plans) 16 bit value to VDP data port during hint... I think you can spent 25% or less CPU time for it. Righ...
by Miquel
Mon Aug 22, 2016 9:02 pm
Forum: SGDK
Topic: [C preprocessor] generating "mirrored" functions
Replies: 3
Views: 1233

Re: [C preprocessor] generating "mirrored" functions

You're going to turn crazy that way. Behave physics differently if you go left or right? Is not just the left and right animation just a y-flip of each other? Behave differently the object if you go left or right? Probably all you need is a flag to know in which direction are you going. And in the p...
by Miquel
Mon Aug 22, 2016 7:59 pm
Forum: SGDK
Topic: What do you use for sorting?
Replies: 15
Views: 3385

Re: What do you use for sorting?

Three remarks: - Probably you don't want to only sort by Y-axis but also group them by type. For example, a cloud will always be behind or on top of other types of objects/sprites. - Like tryphon said it will be better if you work with a list already sorted. When a sprite/object moves you just check...
by Miquel
Mon Aug 22, 2016 5:34 pm
Forum: Video Display Processor
Topic: VDP access from Z80 questions
Replies: 16
Views: 5314

Re: VDP access from Z80 questions

Z80 cannot do 16bit accesses to the VDP, the 8bit accesses done by Z80 (or 68K) to VDP are always seen as 16bit accesses (both halves of the 16bit write will be duplicated). You can get more info from the docs by Charles MacDonald. From Charles documentation: Z80 access to the VDP has the same resu...
by Miquel
Sun Aug 21, 2016 12:57 pm
Forum: Video Display Processor
Topic: VDP access from Z80 questions
Replies: 16
Views: 5314

VDP access from Z80 questions

I'm developing a MD game, at the start I tried to give all the jobs to the 68000, meaning: playfield, sound, graphics and HINT response, so, perhaps I didn't need to program the Z80. I use HINT to change scroll to perform a perspective, very much like Axelay does. Later I discovered that HINT except...