Msx 1 software sprites

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By andrea.denara

Resident (59)

andrea.denara's picture

11-09-2016, 14:03

I know Uridium. It's use tiles to simulate Horizontal scroll.
But what you think about move a single char in all direction?
A definition for an 8x8 char require 64 tiles only for patterns.
My question is about tis dilemma:
Zx spectrum without graphic processor can do that at good speed. Why msx can't?

By jltursan

Prophet (2126)

jltursan's picture

11-09-2016, 16:04

Beacuse MSX desn't have direct VRAM access like other machines. With careful planning you can avoid most of the overhead of accessing to the VRAM through ports; but it can be compared with the fastests routines that can be used in these RAM based machines like "stack-blasting".

A game that makes a full use of software+hardware sprites is "Green Beret", in the classic sense of software sprites. Years ago I made a game that also uses a lot of hardware/software sprites ("Caverns of Titan"); but it's not a real software sprite engine and it's full of tricks.

By ARTRAG

Enlighted (6173)

ARTRAG's picture

11-09-2016, 17:01

Move your 8x8 character in 4 directions two pixels at time. Allow direction changes only at perfect intersections.
Your tile will need only two tiles to be drawn under any condition and you will need exactly 8+8 precomputed tiles in vram to represent it.
If you want to load the tiles on fly you need to transfer 16+16 bytes.
There is no general way to have transparency for colored backgrounds and sprites.

By andrea.denara

Resident (59)

andrea.denara's picture

11-09-2016, 20:34

jltursan wrote:

Beacuse MSX desn't have direct VRAM access like other machines. With careful planning you can avoid most of the overhead of accessing to the VRAM through ports; but it can be compared with the fastests routines that can be used in these RAM based machines like "stack-blasting".

A game that makes a full use of software+hardware sprites is "Green Beret", in the classic sense of software sprites. Years ago I made a game that also uses a lot of hardware/software sprites ("Caverns of Titan"); but it's not a real software sprite engine and it's full of tricks.

Did you use sprite as background? Uhhh anyway very interesting!!!

By MsxKun

Paladin (892)

MsxKun's picture

11-09-2016, 22:23

andrea.denara wrote:

I know Uridium. It's use tiles to simulate Horizontal scroll.
But what you think about move a single char in all direction?
A definition for an 8x8 char require 64 tiles only for patterns.
My question is about tis dilemma:
Zx spectrum without graphic processor can do that at good speed. Why msx can't?

Cause MSX (well, exactly the VDP) was designed in a different way. It has sprites for that job.

By MsxKun

Paladin (892)

MsxKun's picture

11-09-2016, 22:24

jltursan wrote:

A game that makes a full use of software+hardware sprites is "Green Beret", in the classic sense of software sprites.

And it sucks badly Big smile

By snake

Rookie (27)

snake's picture

12-12-2016, 22:50

I fear that pre-shifted tiles will take a huge amount of ram when you deal with complex stuff like the bare hands fight stage of Way Of The Tiger: characters with tons of animation frames, parallax scrolling with lots of items, and background animations too. I wonder what is the solution adopted by developers. Maybe they store each sprite on a temporary ram buffer, then performed a shift on every byte of it, then blit the buffer on pattern generator vram? And how does they perform a masked blit in order to avoid the black square under the sprite? The game engine seems to be complex, and the game is a little slow, but still playable and smooth.

By andrea.denara

Resident (59)

andrea.denara's picture

13-12-2016, 09:23

At the moment i'm working on a scroll routine, the problem is to scroll a (128 x 2) bytes, only 2 lines of chars.
A pre-shifted way cost about 128 x 2 x (8 bytes of pattern + 8 Bytes of colors) x (8 pre shift) = 32 KBytes.
It's too much for only 2 rows shifted.
Maybe I can use some tricks to reduce colors or an hybrid mode where pattern is preshifted and colors have dynamic routine.
So I'm wonder about games as Uridium that use preshifted pattern and rom is only 48Kbytes.

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