prog8/compiler/res/prog8lib/cx16/monogfx.p8
2024-03-12 23:27:15 +01:00

995 lines
30 KiB
Lua

; Monochrome Bitmap pixel graphics routines for the CommanderX16
; Using the full-screen 640x480 and 320x240 screen modes, in 1 bpp mode (black/white).
;
; No text layer is currently shown, but text can be drawn as part of the bitmap itself.
; For color bitmap graphics, see the gfx2 library.
;
; NOTE: a lot of the code here is similar or the same to that in gfx2
; NOTE: For sake of speed, NO BOUNDS CHECKING is performed in most routines!
; You'll have to make sure yourself that you're not writing outside of bitmap boundaries!
monogfx {
%option ignore_unused
; read-only control variables:
uword width = 0
uword height = 0
ubyte mode
const ubyte MODE_NORMAL = %00000000
const ubyte MODE_STIPPLE = %00000001
const ubyte MODE_INVERT = %00000010
sub lores() {
; enable 320*240 bitmap mode
cx16.VERA_CTRL=0
cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11001111) | %00100000 ; enable only layer 1
cx16.VERA_DC_HSCALE = 64
cx16.VERA_DC_VSCALE = 64
cx16.VERA_L1_CONFIG = %00000100
cx16.VERA_L1_MAPBASE = 0
cx16.VERA_L1_TILEBASE = 0
width = 320
height = 240
mode = MODE_NORMAL
clear_screen(0)
}
sub hires() {
; enable 640*480 bitmap mode
cx16.VERA_CTRL=0
cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11001111) | %00100000 ; enable only layer 1
cx16.VERA_DC_HSCALE = 128
cx16.VERA_DC_VSCALE = 128
cx16.VERA_L1_CONFIG = %00000100
cx16.VERA_L1_MAPBASE = 0
cx16.VERA_L1_TILEBASE = %00000001
width = 640
height = 480
mode = MODE_NORMAL
clear_screen(0)
}
sub textmode() {
; back to normal text mode
cx16.r15L = cx16.VERA_DC_VIDEO & %00000111 ; retain chroma + output mode
cbm.CINT()
cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11111000) | cx16.r15L
}
sub drawmode(ubyte dm) {
mode = dm
}
sub clear_screen(ubyte color) {
position(0, 0)
when width {
320 -> {
repeat 240/2/8
cs_innerloop640(color)
}
640 -> {
repeat 480/8
cs_innerloop640(color)
}
}
position(0, 0)
}
sub rect(uword xx, uword yy, uword rwidth, uword rheight, bool draw) {
if rwidth==0 or rheight==0
return
horizontal_line(xx, yy, rwidth, draw)
if rheight==1
return
horizontal_line(xx, yy+rheight-1, rwidth, draw)
vertical_line(xx, yy+1, rheight-2, draw)
if rwidth==1
return
vertical_line(xx+rwidth-1, yy+1, rheight-2, draw)
}
sub fillrect(uword xx, uword yy, uword rwidth, uword rheight, bool draw) {
; Draw a filled rectangle of the given size and color.
; To fill the whole screen, use clear_screen(color) instead - it is much faster.
if rwidth==0
return
repeat rheight {
horizontal_line(xx, yy, rwidth, draw)
yy++
}
}
sub horizontal_line(uword xx, uword yy, uword length, bool draw) {
ubyte[9] masked_starts = [ 0, %00000001, %00000011, %00000111, %00001111, %00011111, %00111111, %01111111, %11111111]
ubyte[9] masked_ends = [ 0, %10000000, %11000000, %11100000, %11110000, %11111000, %11111100, %11111110, %11111111]
if length==0
return
if length<=8 {
; just use 2 byte writes with shifted mask
position2(xx,yy,true)
%asm {{
ldy p8v_length
lda p8v_masked_ends,y
sta cx16.r0L ; save left byte
stz P8ZP_SCRATCH_B1
lda p8v_xx
and #7
beq +
tay
lda cx16.r0L
- lsr a
ror P8ZP_SCRATCH_B1
dey
bne -
sta cx16.r0L ; new left byte
+
lda p8v_mode
lsr a
bcc _dontstipple
; determine stipple pattern
lda p8v_yy
and #1
beq +
lda #%10101010
bne ++
+ lda #%01010101
+ sta P8ZP_SCRATCH_REG
lda cx16.r0L
and P8ZP_SCRATCH_REG
sta cx16.r0L
lda P8ZP_SCRATCH_B1
and P8ZP_SCRATCH_REG
sta P8ZP_SCRATCH_B1
_dontstipple
lda p8v_draw
beq _clear
lda cx16.r0L ; left byte
ora cx16.VERA_DATA1
sta cx16.VERA_DATA0
lda P8ZP_SCRATCH_B1 ; right byte
ora cx16.VERA_DATA1
sta cx16.VERA_DATA0
rts
_clear
lda cx16.r0L ; left byte
eor #255
and cx16.VERA_DATA1
sta cx16.VERA_DATA0
lda P8ZP_SCRATCH_B1 ; right byte
eor #255
and cx16.VERA_DATA1
sta cx16.VERA_DATA0
rts
}}
}
ubyte separate_pixels = (8-lsb(xx)) & 7
if separate_pixels!=0 {
when mode {
MODE_NORMAL -> {
position(xx,yy)
cx16.VERA_ADDR_H &= %00000111 ; vera auto-increment off
if draw
cx16.VERA_DATA0 |= masked_starts[separate_pixels]
else
cx16.VERA_DATA0 &= ~masked_starts[separate_pixels]
xx += separate_pixels
}
MODE_STIPPLE -> {
repeat separate_pixels {
plot(xx, yy, draw)
xx++
}
}
MODE_INVERT -> {
position(xx,yy)
cx16.VERA_ADDR_H &= %00000111 ; vera auto-increment off
if draw
cx16.VERA_DATA0 ^= masked_starts[separate_pixels]
else
cx16.VERA_DATA0 &= masked_starts[separate_pixels]
xx += separate_pixels
}
}
length -= separate_pixels
}
if length!=0 {
position(xx, yy)
separate_pixels = lsb(length) & 7
xx += length & $fff8
%asm {{
lsr p8v_length+1
ror p8v_length
lsr p8v_length+1
ror p8v_length
lsr p8v_length+1
ror p8v_length
lda p8v_draw
bne +
ldy #0 ; black
bra _loop
+ lda p8v_mode
lsr a
bcs _stipple
lsr a
bcs _inverted
ldy #255 ; normal drawing mode
bra _loop
_inverted lda #0
jsr cx16.vaddr_clone
_invertedloop lda p8v_length
ora p8v_length+1
beq _done
lda cx16.VERA_DATA1
eor #255
sta cx16.VERA_DATA0
lda p8v_length
bne +
dec p8v_length+1
+ dec p8v_length
bra _invertedloop
_stipple lda p8v_yy
and #1 ; determine stipple pattern to use
bne +
ldy #%01010101
bra _loop
+ ldy #%10101010
_loop lda p8v_length
ora p8v_length+1
beq _done
sty cx16.VERA_DATA0
lda p8v_length
bne +
dec p8v_length+1
+ dec p8v_length
bra _loop
_done
}}
when mode {
MODE_NORMAL -> {
cx16.VERA_ADDR_H &= %00000111 ; vera auto-increment off
if draw
cx16.VERA_DATA0 |= masked_ends[separate_pixels]
else
cx16.VERA_DATA0 &= ~masked_ends[separate_pixels]
}
MODE_STIPPLE -> {
repeat separate_pixels {
plot(xx, yy, draw)
xx++
}
}
MODE_INVERT -> {
cx16.VERA_ADDR_H &= %00000111 ; vera auto-increment off
if draw
cx16.VERA_DATA0 ^= masked_ends[separate_pixels]
else
cx16.VERA_DATA0 &= masked_ends[separate_pixels]
}
}
}
cx16.VERA_ADDR_H &= %00000111 ; vera auto-increment off again
}
sub safe_horizontal_line(uword xx, uword yy, uword length, bool draw) {
; does bounds checking and clipping
if msb(yy)&$80!=0 or yy>=height
return
if msb(xx)&$80!=0 {
length += xx
xx = 0
}
if xx>=width
return
if xx+length>width
length = width-xx
if length>width
return
horizontal_line(xx, yy, length, draw)
}
sub vertical_line(uword xx, uword yy, uword lheight, bool draw) {
cx16.r15L = monogfx.plot.maskbits[xx as ubyte & 7] ; bitmask
if draw {
%asm {{
lda p8v_mode
and #p8c_MODE_INVERT
beq +
lda #$45 ; eor ZP modifying code
bne ++
+ lda #$05 ; ora ZP modifying code
+ sta drawmode
}}
if mode!=MODE_STIPPLE {
; draw continuous line.
position2(xx,yy,true)
if width==320
set_both_strides(11) ; 40 increment = 1 line in 320 px monochrome
else
set_both_strides(12) ; 80 increment = 1 line in 640 px monochrome
repeat lheight {
%asm {{
lda cx16.VERA_DATA0
drawmode: ora cx16.r15L
sta cx16.VERA_DATA1
}}
}
} else {
; draw stippled line.
if (xx ^ yy)&1==0 {
yy++
lheight--
}
lheight++ ; because it is divided by 2 later, don't round off the last pixel
position2(xx,yy,true)
if width==320
set_both_strides(12) ; 80 increment = 2 line in 320 px monochrome
else
set_both_strides(13) ; 160 increment = 2 line in 640 px monochrome
repeat lheight/2 {
%asm {{
lda cx16.VERA_DATA0
ora cx16.r15L
sta cx16.VERA_DATA1
}}
}
}
} else {
position2(xx,yy,true)
cx16.r15 = ~cx16.r15 ; erase pixels
if width==320
set_both_strides(11) ; 40 increment = 1 line in 320 px monochrome
else
set_both_strides(12) ; 80 increment = 1 line in 640 px monochrome
repeat lheight {
%asm {{
lda cx16.VERA_DATA0
and cx16.r15L
sta cx16.VERA_DATA1
}}
}
}
sub set_both_strides(ubyte stride) {
stride <<= 4
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride
cx16.VERA_CTRL = 1
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride
}
}
sub line(uword @zp x1, uword @zp y1, uword @zp x2, uword @zp y2, bool draw) {
; Bresenham algorithm.
; This code special-cases various quadrant loops to allow simple ++ and -- operations.
if y1>y2 {
; make sure dy is always positive to have only 4 instead of 8 special cases
cx16.r0 = x1
x1 = x2
x2 = cx16.r0
cx16.r0 = y1
y1 = y2
y2 = cx16.r0
}
word @zp dx = (x2 as word)-x1
word @zp dy = (y2 as word)-y1
if dx==0 {
vertical_line(x1, y1, abs(dy) as uword +1, draw)
return
}
if dy==0 {
if x1>x2
x1=x2
horizontal_line(x1, y1, abs(dx) as uword +1, draw)
return
}
word @zp d = 0
cx16.r1L = 1 ;; true ; 'positive_ix'
if dx < 0 {
dx = -dx
cx16.r1L = 0 ;; false
}
word @zp dx2 = dx*2
word @zp dy2 = dy*2
cx16.r14 = x1 ; internal plot X
if dx >= dy {
if cx16.r1L!=0 {
repeat {
plot(cx16.r14, y1, draw)
if cx16.r14==x2
return
cx16.r14++
d += dy2
if d > dx {
y1++
d -= dx2
}
}
} else {
repeat {
plot(cx16.r14, y1, draw)
if cx16.r14==x2
return
cx16.r14--
d += dy2
if d > dx {
y1++
d -= dx2
}
}
}
}
else {
if cx16.r1L!=0 {
repeat {
plot(cx16.r14, y1, draw)
if y1 == y2
return
y1++
d += dx2
if d > dy {
cx16.r14++
d -= dy2
}
}
} else {
repeat {
plot(cx16.r14, y1, draw)
if y1 == y2
return
y1++
d += dx2
if d > dy {
cx16.r14--
d -= dy2
}
}
}
}
}
sub circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, bool draw) {
; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
; Midpoint algorithm.
if radius==0
return
ubyte @zp xx = radius
ubyte @zp yy = 0
word @zp decisionOver2 = (1 as word)-xx
; R14 = internal plot X
; R15 = internal plot Y
while xx>=yy {
cx16.r14 = xcenter + xx
cx16.r15 = ycenter + yy
plotq()
cx16.r14 = xcenter - xx
plotq()
cx16.r14 = xcenter + xx
cx16.r15 = ycenter - yy
plotq()
cx16.r14 = xcenter - xx
plotq()
cx16.r14 = xcenter + yy
cx16.r15 = ycenter + xx
plotq()
cx16.r14 = xcenter - yy
plotq()
cx16.r14 = xcenter + yy
cx16.r15 = ycenter - xx
plotq()
cx16.r14 = xcenter - yy
plotq()
yy++
if decisionOver2>=0 {
xx--
decisionOver2 -= xx*$0002
}
decisionOver2 += yy*$0002
decisionOver2++
}
sub plotq() {
; cx16.r14 = x, cx16.r15 = y, draw=draw
plot(cx16.r14, cx16.r15, draw)
}
}
sub safe_circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, bool draw) {
; Does bounds checking and clipping.
; Midpoint algorithm.
if radius==0
return
ubyte @zp xx = radius
ubyte @zp yy = 0
word @zp decisionOver2 = (1 as word)-xx
; R14 = internal plot X
; R15 = internal plot Y
while xx>=yy {
cx16.r14 = xcenter + xx
cx16.r15 = ycenter + yy
plotq()
cx16.r14 = xcenter - xx
plotq()
cx16.r14 = xcenter + xx
cx16.r15 = ycenter - yy
plotq()
cx16.r14 = xcenter - xx
plotq()
cx16.r14 = xcenter + yy
cx16.r15 = ycenter + xx
plotq()
cx16.r14 = xcenter - yy
plotq()
cx16.r14 = xcenter + yy
cx16.r15 = ycenter - xx
plotq()
cx16.r14 = xcenter - yy
plotq()
yy++
if decisionOver2>=0 {
xx--
decisionOver2 -= xx*$0002
}
decisionOver2 += yy*$0002
decisionOver2++
}
sub plotq() {
; cx16.r14 = x, cx16.r15 = y, draw=draw
safe_plot(cx16.r14, cx16.r15, draw)
}
}
sub disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, bool draw) {
; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
; Midpoint algorithm, filled
if radius==0
return
ubyte @zp yy = 0
word @zp decisionOver2 = (1 as word)-radius
while radius>=yy {
horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, draw)
horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, draw)
horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, draw)
horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, draw)
yy++
if decisionOver2>=0 {
radius--
decisionOver2 -= radius*$0002
}
decisionOver2 += yy*$0002
decisionOver2++
}
}
sub safe_disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, bool draw) {
; Does bounds checking and clipping.
; Midpoint algorithm, filled
if radius==0
return
ubyte @zp yy = 0
word @zp decisionOver2 = (1 as word)-radius
while radius>=yy {
safe_horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, draw)
safe_horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, draw)
safe_horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, draw)
safe_horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, draw)
yy++
if decisionOver2>=0 {
radius--
decisionOver2 -= radius*$0002
}
decisionOver2 += yy*$0002
decisionOver2++
}
}
sub plot(uword @zp xx, uword @zp yy, bool @zp draw) {
ubyte[8] @shared maskbits = [128, 64, 32, 16, 8, 4, 2, 1]
if draw {
; solid color or perhaps stipple
%asm {{
lda p8v_mode
lsr a
bcs +
lsr a
bcs p8l_invert
bra p8l_nostipple
+ ; stipple mode
lda p8v_xx
eor p8v_yy
and #1
}}
if_nz {
nostipple:
prepare()
%asm {{
tsb cx16.VERA_DATA0
}}
}
} else {
; only erase
prepare()
%asm {{
trb cx16.VERA_DATA0
}}
}
return
invert:
prepare()
%asm {{
lda cx16.VERA_DATA0
eor p8v_maskbits,y
sta cx16.VERA_DATA0
}}
return
sub prepare() {
%asm {{
lda p8v_xx
and #7
pha ; xbits
}}
xx /= 8
if width==320
xx += yy*(320/8)
else
xx += yy*(640/8)
%asm {{
stz cx16.VERA_CTRL
stz cx16.VERA_ADDR_H
lda p8v_xx+1
sta cx16.VERA_ADDR_M
lda p8v_xx
sta cx16.VERA_ADDR_L
ply ; xbits
lda p8v_maskbits,y
}}
}
}
sub safe_plot(uword xx, uword yy, bool draw) {
; A plot that does bounds checks to see if the pixel is inside the screen.
if msb(xx)&$80!=0 or msb(yy)&$80!=0
return
if xx >= width or yy >= height
return
plot(xx, yy, draw)
}
sub pget(uword @zp xx, uword yy) -> bool {
%asm {{
lda p8v_xx
and #7
pha ; xbits
}}
xx /= 8
if width==320
xx += yy*(320/8)
else
xx += yy*(640/8)
%asm {{
stz cx16.VERA_CTRL
stz cx16.VERA_ADDR_H
lda p8v_xx+1
sta cx16.VERA_ADDR_M
lda p8v_xx
sta cx16.VERA_ADDR_L
ply ; xbits
lda p8s_plot.p8v_maskbits,y
and cx16.VERA_DATA0
beq +
lda #1
+ rts
}}
}
sub fill(uword x, uword y, bool draw) {
; Non-recursive scanline flood fill.
; based loosely on code found here https://www.codeproject.com/Articles/6017/QuickFill-An-efficient-flood-fill-algorithm
; with the fixes applied to the seedfill_4 routine as mentioned in the comments.
const ubyte MAXDEPTH = 64
word @zp xx = x as word
word @zp yy = y as word
word[MAXDEPTH] @split @shared stack_xl
word[MAXDEPTH] @split @shared stack_xr
word[MAXDEPTH] @split @shared stack_y
byte[MAXDEPTH] @shared stack_dy
cx16.r12L = 0 ; stack pointer
word x1
word x2
byte dy
cx16.r10L = draw as ubyte
sub push_stack(word sxl, word sxr, word sy, byte sdy) {
if cx16.r12L==MAXDEPTH
return
cx16.r0s = sy+sdy
if cx16.r0s>=0 and cx16.r0s<=height-1 {
;; stack_xl[cx16.r12L] = sxl
;; stack_xr[cx16.r12L] = sxr
;; stack_y[cx16.r12L] = sy
;; stack_dy[cx16.r12L] = sdy
;; cx16.r12L++
%asm {{
ldy cx16.r12L
lda p8v_sxl
sta p8v_stack_xl_lsb,y
lda p8v_sxl+1
sta p8v_stack_xl_msb,y
lda p8v_sxr
sta p8v_stack_xr_lsb,y
lda p8v_sxr+1
sta p8v_stack_xr_msb,y
lda p8v_sy
sta p8v_stack_y_lsb,y
lda p8v_sy+1
sta p8v_stack_y_msb,y
ldy cx16.r12L
lda p8v_sdy
sta p8v_stack_dy,y
inc cx16.r12L
}}
}
}
sub pop_stack() {
;; cx16.r12L--
;; x1 = stack_xl[cx16.r12L]
;; x2 = stack_xr[cx16.r12L]
;; y = stack_y[cx16.r12L]
;; dy = stack_dy[cx16.r12L]
%asm {{
dec cx16.r12L
ldy cx16.r12L
lda p8v_stack_xl_lsb,y
sta p8v_x1
lda p8v_stack_xl_msb,y
sta p8v_x1+1
lda p8v_stack_xr_lsb,y
sta p8v_x2
lda p8v_stack_xr_msb,y
sta p8v_x2+1
lda p8v_stack_y_lsb,y
sta p8v_yy
lda p8v_stack_y_msb,y
sta p8v_yy+1
ldy cx16.r12L
lda p8v_stack_dy,y
sta p8v_dy
}}
yy+=dy
}
cx16.r11L = pget(xx as uword, yy as uword) as ubyte ; old_color
if cx16.r11L == cx16.r10L
return
if xx<0 or xx>width-1 or yy<0 or yy>height-1
return
push_stack(xx, xx, yy, 1)
push_stack(xx, xx, yy + 1, -1)
word left = 0
while cx16.r12L!=0 {
pop_stack()
xx = x1
while xx >= 0 {
if pget(xx as uword, yy as uword) as ubyte != cx16.r11L
break
xx--
}
if x1!=xx
horizontal_line(xx as uword+1, yy as uword, x1-xx as uword, cx16.r10L as bool)
else
goto skip
left = xx + 1
if left < x1
push_stack(left, x1 - 1, yy, -dy)
xx = x1 + 1
do {
cx16.r9s = xx
while xx <= width-1 {
if pget(xx as uword, yy as uword) as ubyte != cx16.r11L
break
xx++
}
if cx16.r9s!=xx
horizontal_line(cx16.r9, yy as uword, xx-cx16.r9s as uword, cx16.r10L as bool)
push_stack(left, xx - 1, yy, dy)
if xx > x2 + 1
push_stack(x2 + 1, xx - 1, yy, -dy)
skip:
xx++
while xx <= x2 {
if pget(xx as uword, yy as uword) as ubyte == cx16.r11L
break
xx++
}
left = xx
} until xx>x2
}
}
sub position(uword @zp xx, uword yy) {
if width==320
cx16.r0 = yy*(320/8)
else
cx16.r0 = yy*(640/8)
cx16.vaddr(0, cx16.r0+(xx/8), 0, 1)
}
sub position2(uword @zp xx, uword yy, bool also_port_1) {
position(xx, yy)
if also_port_1
cx16.vaddr_clone(0)
}
const ubyte charset_bank = $1
const uword charset_addr = $f000 ; in bank 1, so $1f000
sub text_charset(ubyte charset) {
; -- select the text charset to use with the text() routine
; the charset number is the same as for the cx16.screen_set_charset() ROM function.
; 1 = ISO charset, 2 = PETSCII uppercase+graphs, 3= PETSCII uppercase+lowercase.
cx16.screen_set_charset(charset, 0)
}
sub text(uword @zp xx, uword yy, bool draw, str sctextptr) {
; -- Write some text at the given pixel position. The text string must be in screencode encoding (not petscii!).
; You must also have called text_charset() first to select and prepare the character set to use.
uword chardataptr
ubyte[8] @shared char_bitmap_bytes_left
ubyte[8] @shared char_bitmap_bytes_right
cx16.r3 = sctextptr
%asm {{
lda p8v_mode
cmp #p8c_MODE_INVERT
beq +
lda #$0d ; ORA abs modifying code
bne ++
+ lda #$4d ; EOR abs modifying code
+ sta cdraw_mod1
sta cdraw_mod2
}}
while @(cx16.r3)!=0 {
chardataptr = charset_addr + @(cx16.r3) * $0008
; copy the character bitmap into RAM
cx16.vaddr_autoincr(charset_bank, chardataptr, 0, 1)
%asm {{
; pre-shift the bits
lda p8s_text.p8v_xx
and #7
sta P8ZP_SCRATCH_B1
ldy #0
- lda cx16.VERA_DATA0
stz P8ZP_SCRATCH_REG
ldx P8ZP_SCRATCH_B1
cpx #0
beq +
- lsr a
ror P8ZP_SCRATCH_REG
dex
bne -
+ sta p8v_char_bitmap_bytes_left,y
lda P8ZP_SCRATCH_REG
sta p8v_char_bitmap_bytes_right,y
iny
cpy #8
bne --
}}
; left part of shifted char
position2(xx, yy, true)
set_autoincrs()
if draw {
%asm {{
ldy #0
- lda p8v_char_bitmap_bytes_left,y
cdraw_mod1 ora cx16.VERA_DATA1
sta cx16.VERA_DATA0
iny
cpy #8
bne -
}}
} else {
%asm {{
ldy #0
- lda p8v_char_bitmap_bytes_left,y
eor #255
and cx16.VERA_DATA1
sta cx16.VERA_DATA0
iny
cpy #8
bne -
}}
}
; right part of shifted char
if lsb(xx) & 7 !=0 {
position2(xx+8, yy, true)
set_autoincrs()
if draw {
%asm {{
ldy #0
- lda p8v_char_bitmap_bytes_right,y
cdraw_mod2 ora cx16.VERA_DATA1
sta cx16.VERA_DATA0
iny
cpy #8
bne -
}}
} else {
%asm {{
ldy #0
- lda p8v_char_bitmap_bytes_right,y
eor #255
and cx16.VERA_DATA1
sta cx16.VERA_DATA0
iny
cpy #8
bne -
}}
}
}
cx16.r3++
xx += 8
}
sub set_autoincrs() {
; set autoincrements to go to next pixel row (40 or 80 increment)
if width==320 {
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & $0f | (11<<4)
cx16.VERA_CTRL = 1
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & $0f | (11<<4)
} else {
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & $0f | (12<<4)
cx16.VERA_CTRL = 1
cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & $0f | (12<<4)
}
}
}
asmsub cs_innerloop640(ubyte color @A) clobbers(Y) {
; using verafx 32 bits writes here would make this faster but it's safer to
; use verafx only explicitly when you know what you're doing.
%asm {{
cmp #0
beq +
lda #255
+ ldy #80
- sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
sta cx16.VERA_DATA0
dey
bne -
rts
}}
}
}