dos33fsprogs/games/lemm/hgr_sprite.s
2022-03-09 00:35:13 -05:00

221 lines
3.0 KiB
ArmAsm

;===========================================
; hgr draw sprite (only at 7-bit boundaries)
;===========================================
; SPRITE in INL/INH
; Location at CURSOR_X CURSOR_Y
; xsize, ysize in first two bytes
; sprite AT INL/INH
hgr_draw_sprite:
ldy #0
lda (INL),Y ; load xsize
clc
adc CURSOR_X
sta sprite_width_end_smc+1 ; self modify for end of line
iny ; load ysize
lda (INL),Y
sta sprite_ysize_smc+1 ; self modify
; skip the xsize/ysize and point to sprite
clc
lda INL ; 16-bit add
adc #2
sta sprite_smc1+1
lda INH
adc #0
sta sprite_smc1+2
ldx #0 ; X is pointer offset
stx MASK ; actual row
hgr_sprite_yloop:
lda MASK ; row
clc
adc CURSOR_Y ; add in cursor_y
; calc GBASL/GBASH
tay ; get output ROW into GBASL/H
lda hposn_low,Y
sta GBASL
lda hposn_high,Y
; eor #$00 draws on page2
; eor #$60 draws on page1
hgr_sprite_page_smc:
eor #$00
sta GBASH
ldy CURSOR_X
sprite_inner_loop:
sprite_smc1:
lda $d000 ; get sprite pattern
sta (GBASL),Y ; store out
inx
iny
inc sprite_smc1+1
bne sprite_noflo
inc sprite_smc1+2
sprite_noflo:
sprite_width_end_smc:
cpy #6
bne sprite_inner_loop
inc MASK ; row
lda MASK ; row
sprite_ysize_smc:
cmp #31
bne hgr_sprite_yloop
rts
;===========================================
; hgr draw sprite (only at 7-bit boundaries)
;===========================================
; autoshift version
; assumes sprite is drawn for even column
; and shifts it if in odd column
; SPRITE in INL/INH
; Location at CURSOR_X CURSOR_Y
; xsize, ysize in first two bytes
; sprite AT INL/INH
hgr_draw_sprite_autoshift:
; self modify to shift for odd start location
; SEC=$38 0b0011 1000 CLC=$18 0b0001 10000
lda CURSOR_X
lsr
bcc make_it_even
make_it_odd:
lda #$18
bne make_it_so
make_it_even:
lda #$38
make_it_so:
sta odd_even_smc
ldy #0
lda (INL),Y ; load xsize
clc
adc CURSOR_X
sta sprite_width_end_smc_as+1 ; self modify for end of line
iny ; load ysize
lda (INL),Y
sta sprite_ysize_smc_as+1 ; self modify
; skip the xsize/ysize and point to sprite
clc
lda INL ; 16-bit add
adc #2
sta sprite_smc1_as+1
lda INH
adc #0
sta sprite_smc1_as+2
ldx #0 ; X is pointer offset
stx MASK ; actual row
hgr_sprite_yloop_as:
lda MASK ; row
clc
adc CURSOR_Y ; add in cursor_y
; calc GBASL/GBASH
tay ; get output ROW into GBASL/H
lda hposn_low,Y
sta GBASL
lda hposn_high,Y
; eor #$00 draws on page2
; eor #$60 draws on page1
hgr_sprite_page_smc_as:
eor #$00
sta GBASH
ldy CURSOR_X
sprite_inner_loop_as:
sprite_smc1_as:
lda $d000 ; get sprite pattern
; lsr
odd_even_smc:
sec
bcs no_adjust
asl
php
clc
lsr
plp
ror
no_adjust:
;? Xcababab
;X cababab?
;? X0cababa
; clc ; rol asl
; rol
sta (GBASL),Y ; store out
inx
iny
inc sprite_smc1_as+1
bne sprite_noflo_as
inc sprite_smc1_as+2
sprite_noflo_as:
sprite_width_end_smc_as:
cpy #6
bne sprite_inner_loop_as
inc MASK ; row
lda MASK ; row
sprite_ysize_smc_as:
cmp #31
bne hgr_sprite_yloop_as
rts