SpiceWare's Blog

I hear you about keeping the datastreams the same. It also makes it a lot easier to trouble shoot.

 

 

You could change some of those SLEEP 3's to jumps or branches to identical code and save quite a few bytes. For example this code is identical in P0EarlyHM22, P0EarlyHM25, P0EarlyHM30, P0EarlyHM35, P0EarlyHM40, and P0EarlyHM45.

        SLEEP 3                 ; 3 52
        lda #<DS_PF2R           ; 2 54
        sta PF2                 ; 3 57 - PF2R, 50-65
        lda #<DS_PF0L_BL        ; 2 59
        sta PF0                 ; 3 62 - PF0L, after 55
        sta ENABL               ; 3 65 - any, on VDEL
        lda #<DS_PF1L           ; 2 67
        sta PF1                 ; 3 70 - PF1L, 66-28
        sta HMOVE               ; 3 73 - can be on 73 or 74
        lda #<DS_GRP1           ; 2 75 - PLAYER + 3
; start of event + 3, the 4th scanline of reposition player 1        
        sta GRP1                ; 3 78/2        
        lda #<DS_COLUP1         ; 2  4
        sta COLUP1              ; 3  7
        lda #<DS_COLUP0         ; 2  9 - COLOR + 3
        sta NUSIZ0              ; 3 12
        sty ENAM1               ; 3 15
        lda #<DS_EVENT_M0       ; 2 17 - EVENT + 3
        sta ENAM0               ; 3 20
        sta HMP0                ; 3 23 - must be $8x
        jmp Rentry26            ; 3 26

Or is this sleep delay a reserve for something future?

That's the plan.

 

I've started to implement an X position test, like I did before, so I can confirm the players are correctly positioned for every X value. The test routines will also be used to make sure the optimized routines still work correctly.

 

Oops - just noticed that the "start of event" comment has the wrong player #.

How does flicker mitigation work? Or, is there a particular post that deals with it?

While the datastream usage has changed, this blog entry explains how the sprite routines work to minimize flicker.

When I rewrite the sprite driver, I'll post a detailed blog entry about how the routines work to minimize flicker.

 

Based on the prior Frantic reboot, there will be 2 more updates before the sprite driver is rewritten: test of X routines and test of playfield updates.

 

The sprite driver rewrite might happen this weekend, though dad returned from Nigeria yesterday so it'll most likely be next week.