Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.
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# Loading images from disk, rendering images to screen.
#
# Currently supports ASCII Netpbm formats.
# https://en.wikipedia.org/wiki/Netpbm#File_formats
type image {
type: int # supported types:
# 1: portable bitmap (P1) - pixels 0 or 1
# 2: portable greymap (P2) - pixels 1-byte greyscale values
# 3: portable pixmap (P3) - pixels 3-byte rgb values
max: int
width: int
height: int
data: (handle array byte)
}
fn initialize-image _self: (addr image), in: (addr stream byte) {
var self/esi: (addr image) <- copy _self
var mode-storage: slice
var mode/ecx: (addr slice) <- address mode-storage
next-word-skipping-comments in, mode
{
var P1?/eax: boolean <- slice-equal? mode, "P1"
compare P1?, 0/false
break-if-=
var type-a/eax: (addr int) <- get self, type
copy-to *type-a, 1/ppm
initialize-image-from-pbm self, in
return
}
{
var P2?/eax: boolean <- slice-equal? mode, "P2"
compare P2?, 0/false
break-if-=
var type-a/eax: (addr int) <- get self, type
copy-to *type-a, 2/pgm
initialize-image-from-pgm self, in
return
}
{
var P3?/eax: boolean <- slice-equal? mode, "P3"
compare P3?, 0/false
break-if-=
var type-a/eax: (addr int) <- get self, type
copy-to *type-a, 3/ppm
initialize-image-from-ppm self, in
return
}
abort "initialize-image: unrecognized image type"
}
# dispatch to a few variants with mostly identical boilerplate
# TODO: if we have more resolution we could actually use it to improve
# dithering
fn render-image screen: (addr screen), _img: (addr image), xmin: int, ymin: int, width: int, height: int {
var img/esi: (addr image) <- copy _img
var type-a/eax: (addr int) <- get img, type
{
compare *type-a, 1/pbm
break-if-!=
render-pbm-image screen, img, xmin, ymin, width, height
return
}
{
compare *type-a, 2/pgm
break-if-!=
var img2-storage: image
var img2/edi: (addr image) <- address img2-storage
dither-pgm-unordered img, img2
render-raw-image screen, img2, xmin, ymin, width, height
return
}
{
compare *type-a, 3/ppm
break-if-!=
var img2-storage: image
var img2/edi: (addr image) <- address img2-storage
dither-ppm-unordered img, img2
render-raw-image screen, img2, xmin, ymin, width, height
return
}
#? abort "render-image: unrecognized image type"
}
## helpers
# import a black-and-white ascii bitmap (each pixel is 0 or 1)
fn initialize-image-from-pbm _self: (addr image), in: (addr stream byte) {
var self/esi: (addr image) <- copy _self
var curr-word-storage: slice
var curr-word/ecx: (addr slice) <- address curr-word-storage
# load width, height
next-word-skipping-comments in, curr-word
var tmp/eax: int <- parse-decimal-int-from-slice curr-word
var width/edx: int <- copy tmp
next-word-skipping-comments in, curr-word
tmp <- parse-decimal-int-from-slice curr-word
var height/ebx: int <- copy tmp
# save width, height
var dest/eax: (addr int) <- get self, width
copy-to *dest, width
dest <- get self, height
copy-to *dest, height
# initialize data
var capacity/edx: int <- copy width
capacity <- multiply height
var data-ah/edi: (addr handle array byte) <- get self, data
populate data-ah, capacity
var _data/eax: (addr array byte) <- lookup *data-ah
var data/edi: (addr array byte) <- copy _data
var i/ebx: int <- copy 0
{
compare i, capacity
break-if->=
next-word-skipping-comments in, curr-word
var src/eax: int <- parse-decimal-int-from-slice curr-word
{
var dest/ecx: (addr byte) <- index data, i
copy-byte-to *dest, src
}
i <- increment
loop
}
}
# render a black-and-white ascii bitmap (each pixel is 0 or 1)
fn render-pbm-image screen: (addr screen), _img: (addr image), xmin: int, ymin: int, width: int, height: int {
var img/esi: (addr image) <- copy _img
# yratio = height/img->height
var img-height-a/eax: (addr int) <- get img, height
var img-height/xmm0: float <- convert *img-height-a
var yratio/xmm1: float <- convert height
yratio <- divide img-height
# xratio = width/img->width
var img-width-a/eax: (addr int) <- get img, width
var img-width/ebx: int <- copy *img-width-a
var img-width-f/xmm0: float <- convert img-width
var xratio/xmm2: float <- convert width
xratio <- divide img-width-f
# esi = img->data
var img-data-ah/eax: (addr handle array byte) <- get img, data
var _img-data/eax: (addr array byte) <- lookup *img-data-ah
var img-data/esi: (addr array byte) <- copy _img-data
var len/edi: int <- length img-data
#
var one/eax: int <- copy 1
var one-f/xmm3: float <- convert one
var width-f/xmm4: float <- convert width
var height-f/xmm5: float <- convert height
var zero/eax: int <- copy 0
var zero-f/xmm0: float <- convert zero
var y/xmm6: float <- copy zero-f
{
compare y, height-f
break-if-float>=
var imgy-f/xmm5: float <- copy y
imgy-f <- divide yratio
var imgy/edx: int <- truncate imgy-f
var x/xmm7: float <- copy zero-f
{
compare x, width-f
break-if-float>=
var imgx-f/xmm5: float <- copy x
imgx-f <- divide xratio
var imgx/ecx: int <- truncate imgx-f
var idx/eax: int <- copy imgy
idx <- multiply img-width
idx <- add imgx
# error info in case we rounded wrong and 'index' will fail bounds-check
compare idx, len
{
break-if-<
set-cursor-position 0/screen, 0x20/x 0x20/y
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgx, 3/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgy, 4/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, idx, 5/fg 0/bg
}
var src-a/eax: (addr byte) <- index img-data, idx
var src/eax: byte <- copy-byte *src-a
var color-int/eax: int <- copy src
{
compare color-int, 0/black
break-if-=
color-int <- copy 0xf/white
}
var screenx/ecx: int <- convert x
screenx <- add xmin
var screeny/edx: int <- convert y
screeny <- add ymin
pixel screen, screenx, screeny, color-int
x <- add one-f
loop
}
y <- add one-f
loop
}
}
# import a greyscale ascii "greymap" (each pixel is a shade of grey from 0 to 255)
fn initialize-image-from-pgm _self: (addr image), in: (addr stream byte) {
var self/esi: (addr image) <- copy _self
var curr-word-storage: slice
var curr-word/ecx: (addr slice) <- address curr-word-storage
# load width, height
next-word-skipping-comments in, curr-word
var tmp/eax: int <- parse-decimal-int-from-slice curr-word
var width/edx: int <- copy tmp
next-word-skipping-comments in, curr-word
tmp <- parse-decimal-int-from-slice curr-word
var height/ebx: int <- copy tmp
# check and save color levels
next-word-skipping-comments in, curr-word
{
tmp <- parse-decimal-int-from-slice curr-word
compare tmp, 0xff
break-if-=
draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "levels of grey is not 255; continuing and hoping for the best", 0x2b/fg 0/bg
}
var dest/edi: (addr int) <- get self, max
copy-to *dest, tmp
# save width, height
dest <- get self, width
copy-to *dest, width
dest <- get self, height
copy-to *dest, height
# initialize data
var capacity/edx: int <- copy width
capacity <- multiply height
var data-ah/edi: (addr handle array byte) <- get self, data
populate data-ah, capacity
var _data/eax: (addr array byte) <- lookup *data-ah
var data/edi: (addr array byte) <- copy _data
var i/ebx: int <- copy 0
{
compare i, capacity
break-if->=
next-word-skipping-comments in, curr-word
var src/eax: int <- parse-decimal-int-from-slice curr-word
{
var dest/ecx: (addr byte) <- index data, i
copy-byte-to *dest, src
}
i <- increment
loop
}
}
# render a greyscale ascii "greymap" (each pixel is a shade of grey from 0 to 255) by quantizing the shades
fn render-pgm-image screen: (addr screen), _img: (addr image), xmin: int, ymin: int, width: int, height: int {
var img/esi: (addr image) <- copy _img
# yratio = height/img->height
var img-height-a/eax: (addr int) <- get img, height
var img-height/xmm0: float <- convert *img-height-a
var yratio/xmm1: float <- convert height
yratio <- divide img-height
# xratio = width/img->width
var img-width-a/eax: (addr int) <- get img, width
var img-width/ebx: int <- copy *img-width-a
var img-width-f/xmm0: float <- convert img-width
var xratio/xmm2: float <- convert width
xratio <- divide img-width-f
# esi = img->data
var img-data-ah/eax: (addr handle array byte) <- get img, data
var _img-data/eax: (addr array byte) <- lookup *img-data-ah
var img-data/esi: (addr array byte) <- copy _img-data
var len/edi: int <- length img-data
#
var one/eax: int <- copy 1
var one-f/xmm3: float <- convert one
var width-f/xmm4: float <- convert width
var height-f/xmm5: float <- convert height
var zero/eax: int <- copy 0
var zero-f/xmm0: float <- convert zero
var y/xmm6: float <- copy zero-f
{
compare y, height-f
break-if-float>=
var imgy-f/xmm5: float <- copy y
imgy-f <- divide yratio
var imgy/edx: int <- truncate imgy-f
var x/xmm7: float <- copy zero-f
{
compare x, width-f
break-if-float>=
var imgx-f/xmm5: float <- copy x
imgx-f <- divide xratio
var imgx/ecx: int <- truncate imgx-f
var idx/eax: int <- copy imgy
idx <- multiply img-width
idx <- add imgx
# error info in case we rounded wrong and 'index' will fail bounds-check
compare idx, len
{
break-if-<
set-cursor-position 0/screen, 0x20/x 0x20/y
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgx, 3/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgy, 4/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, idx, 5/fg 0/bg
}
var src-a/eax: (addr byte) <- index img-data, idx
var src/eax: byte <- copy-byte *src-a
var color-int/eax: int <- nearest-grey src
var screenx/ecx: int <- convert x
screenx <- add xmin
var screeny/edx: int <- convert y
screeny <- add ymin
pixel screen, screenx, screeny, color-int
x <- add one-f
loop
}
y <- add one-f
loop
}
}
fn nearest-grey level-255: byte -> _/eax: int {
var result/eax: int <- copy level-255
result <- shift-right 4
result <- add 0x10
return result
}
fn dither-pgm-unordered-monochrome _src: (addr image), _dest: (addr image) {
var src/esi: (addr image) <- copy _src
var dest/edi: (addr image) <- copy _dest
# copy 'width'
var src-width-a/eax: (addr int) <- get src, width
var tmp/eax: int <- copy *src-width-a
var src-width: int
copy-to src-width, tmp
{
var dest-width-a/edx: (addr int) <- get dest, width
copy-to *dest-width-a, tmp
}
# copy 'height'
var src-height-a/eax: (addr int) <- get src, height
var tmp/eax: int <- copy *src-height-a
var src-height: int
copy-to src-height, tmp
{
var dest-height-a/ecx: (addr int) <- get dest, height
copy-to *dest-height-a, tmp
}
# transform 'data'
var capacity/ebx: int <- copy src-width
capacity <- multiply src-height
var dest/edi: (addr image) <- copy _dest
var dest-data-ah/eax: (addr handle array byte) <- get dest, data
populate dest-data-ah, capacity
var _dest-data/eax: (addr array byte) <- lookup *dest-data-ah
var dest-data/edi: (addr array byte) <- copy _dest-data
# needs a buffer to temporarily hold more than 256 levels of precision
var errors-storage: (array int 0xc0000)
var errors/ebx: (addr array int) <- address errors-storage
var src-data-ah/eax: (addr handle array byte) <- get src, data
var _src-data/eax: (addr array byte) <- lookup *src-data-ah
var src-data/esi: (addr array byte) <- copy _src-data
var y/edx: int <- copy 0
{
compare y, src-height
break-if->=
var x/ecx: int <- copy 0
{
compare x, src-width
break-if->=
var curr/eax: byte <- _read-pgm-buffer src-data, x, y, src-width
var curr-int/eax: int <- copy curr
curr-int <- shift-left 0x10 # we have 32 bits; we'll use 16 bits for the fraction and leave 8 for unanticipated overflow
var error/esi: int <- _read-dithering-error errors, x, y, src-width
error <- add curr-int
$dither-pgm-unordered-monochrome:update-error: {
compare error, 0x800000
{
break-if->=
_write-raw-buffer dest-data, x, y, src-width, 0/black
break $dither-pgm-unordered-monochrome:update-error
}
_write-raw-buffer dest-data, x, y, src-width, 1/white
error <- subtract 0xff0000
}
_diffuse-dithering-error-floyd-steinberg errors, x, y, src-width, src-height, error
x <- increment
loop
}
move-cursor-to-left-margin-of-next-line 0/screen
y <- increment
loop
}
}
fn dither-pgm-unordered _src: (addr image), _dest: (addr image) {
var src/esi: (addr image) <- copy _src
var dest/edi: (addr image) <- copy _dest
# copy 'width'
var src-width-a/eax: (addr int) <- get src, width
var tmp/eax: int <- copy *src-width-a
var src-width: int
copy-to src-width, tmp
{
var dest-width-a/edx: (addr int) <- get dest, width
copy-to *dest-width-a, tmp
}
# copy 'height'
var src-height-a/eax: (addr int) <- get src, height
var tmp/eax: int <- copy *src-height-a
var src-height: int
copy-to src-height, tmp
{
var dest-height-a/ecx: (addr int) <- get dest, height
copy-to *dest-height-a, tmp
}
# compute scaling factor 255/max
var target-scale/eax: int <- copy 0xff
var scale-f/xmm7: float <- convert target-scale
var src-max-a/eax: (addr int) <- get src, max
var tmp-f/xmm0: float <- convert *src-max-a
scale-f <- divide tmp-f
# transform 'data'
var capacity/ebx: int <- copy src-width
capacity <- multiply src-height
var dest/edi: (addr image) <- copy _dest
var dest-data-ah/eax: (addr handle array byte) <- get dest, data
populate dest-data-ah, capacity
var _dest-data/eax: (addr array byte) <- lookup *dest-data-ah
var dest-data/edi: (addr array byte) <- copy _dest-data
# needs a buffer to temporarily hold more than 256 levels of precision
var errors-storage: (array int 0xc0000)
var errors/ebx: (addr array int) <- address errors-storage
var src-data-ah/eax: (addr handle array byte) <- get src, data
var _src-data/eax: (addr array byte) <- lookup *src-data-ah
var src-data/esi: (addr array byte) <- copy _src-data
var y/edx: int <- copy 0
{
compare y, src-height
break-if->=
var x/ecx: int <- copy 0
{
compare x, src-width
break-if->=
var initial-color/eax: byte <- _read-pgm-buffer src-data, x, y, src-width
# . scale to 255 levels
var initial-color-int/eax: int <- copy initial-color
var initial-color-f/xmm0: float <- convert initial-color-int
initial-color-f <- multiply scale-f
initial-color-int <- convert initial-color-f
var error/esi: int <- _read-dithering-error errors, x, y, src-width
# error += (initial-color << 16)
{
var tmp/eax: int <- copy initial-color-int
tmp <- shift-left 0x10 # we have 32 bits; we'll use 16 bits for the fraction and leave 8 for unanticipated overflow
error <- add tmp
}
# nearest-color = nearest(error >> 16)
var nearest-color/eax: int <- copy error
nearest-color <- shift-right-signed 0x10
{
compare nearest-color, 0
break-if->=
nearest-color <- copy 0
}
{
compare nearest-color, 0xf0
break-if-<=
nearest-color <- copy 0xf0
}
# . truncate last 4 bits
nearest-color <- and 0xf0
# error -= (nearest-color << 16)
{
var tmp/eax: int <- copy nearest-color
tmp <- shift-left 0x10
error <- subtract tmp
}
# color-index = (nearest-color >> 4 + 16)
var color-index/eax: int <- copy nearest-color
color-index <- shift-right 4
color-index <- add 0x10
var color-index-byte/eax: byte <- copy-byte color-index
_write-raw-buffer dest-data, x, y, src-width, color-index-byte
_diffuse-dithering-error-floyd-steinberg errors, x, y, src-width, src-height, error
x <- increment
loop
}
y <- increment
loop
}
}
# Use Floyd-Steinberg algorithm for diffusing error at x, y in a 2D grid of
# dimensions (width, height)
#
# https://tannerhelland.com/2012/12/28/dithering-eleven-algorithms-source-code.html
#
# Error is currently a fixed-point number with 16-bit fraction. But
# interestingly this function doesn't care about that.
fn _diffuse-dithering-error-floyd-steinberg errors: (addr array int), x: int, y: int, width: int, height: int, error: int {
{
compare error, 0
break-if-!=
return
}
var width-1/esi: int <- copy width
width-1 <- decrement
var height-1/edi: int <- copy height
height-1 <- decrement
# delta = error/16
#? show-errors errors, width, height, x, y
var delta/ecx: int <- copy error
delta <- shift-right-signed 4
# In Floyd-Steinberg, each pixel X transmits its errors to surrounding
# pixels in the following proportion:
# X 7/16
# 3/16 5/16 1/16
var x/edx: int <- copy x
{
compare x, width-1
break-if->=
var tmp/eax: int <- copy 7
tmp <- multiply delta
var xright/edx: int <- copy x
xright <- increment
_accumulate-dithering-error errors, xright, y, width, tmp
}
var y/ebx: int <- copy y
{
compare y, height-1
break-if-<
return
}
var ybelow: int
copy-to ybelow, y
increment ybelow
{
compare x, 0
break-if-<=
var tmp/eax: int <- copy 3
tmp <- multiply delta
var xleft/edx: int <- copy x
xleft <- decrement
_accumulate-dithering-error errors, xleft, ybelow, width, tmp
}
{
var tmp/eax: int <- copy 5
tmp <- multiply delta
_accumulate-dithering-error errors, x, ybelow, width, tmp
}
{
compare x, width-1
break-if->=
var xright/edx: int <- copy x
xright <- increment
_accumulate-dithering-error errors, xright, ybelow, width, delta
}
#? show-errors errors, width, height, x, y
}
fn _accumulate-dithering-error errors: (addr array int), x: int, y: int, width: int, error: int {
var curr/esi: int <- _read-dithering-error errors, x, y, width
curr <- add error
_write-dithering-error errors, x, y, width, curr
}
fn _read-dithering-error _errors: (addr array int), x: int, y: int, width: int -> _/esi: int {
var errors/esi: (addr array int) <- copy _errors
var idx/ecx: int <- copy y
idx <- multiply width
idx <- add x
var result-a/eax: (addr int) <- index errors, idx
return *result-a
}
fn _write-dithering-error _errors: (addr array int), x: int, y: int, width: int, val: int {
var errors/esi: (addr array int) <- copy _errors
var idx/ecx: int <- copy y
idx <- multiply width
idx <- add x
#? draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, idx, 7/fg 0/bg
#? move-cursor-to-left-margin-of-next-line 0/screen
var src/eax: int <- copy val
var dest-a/edi: (addr int) <- index errors, idx
copy-to *dest-a, src
}
fn _read-pgm-buffer _buf: (addr array byte), x: int, y: int, width: int -> _/eax: byte {
var buf/esi: (addr array byte) <- copy _buf
var idx/ecx: int <- copy y
idx <- multiply width
idx <- add x
var result-a/eax: (addr byte) <- index buf, idx
var result/eax: byte <- copy-byte *result-a
return result
}
fn _write-raw-buffer _buf: (addr array byte), x: int, y: int, width: int, val: byte {
var buf/esi: (addr array byte) <- copy _buf
var idx/ecx: int <- copy y
idx <- multiply width
idx <- add x
var src/eax: byte <- copy val
var dest-a/edi: (addr byte) <- index buf, idx
copy-byte-to *dest-a, src
}
# some debugging helpers
fn show-errors errors: (addr array int), width: int, height: int, x: int, y: int {
compare y, 1
{
break-if-=
return
}
compare x, 0
{
break-if-=
return
}
var y/edx: int <- copy 0
{
compare y, height
break-if->=
var x/ecx: int <- copy 0
{
compare x, width
break-if->=
var error/esi: int <- _read-dithering-error errors, x, y, width
psd "e", error, 5/fg, x, y
x <- increment
loop
}
move-cursor-to-left-margin-of-next-line 0/screen
y <- increment
loop
}
}
fn psd s: (addr array byte), d: int, fg: int, x: int, y: int {
{
compare y, 0x18
break-if->=
return
}
{
compare y, 0x1c
break-if-<=
return
}
{
compare x, 0x40
break-if->=
return
}
#? {
#? compare x, 0x48
#? break-if-<=
#? return
#? }
draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, s, 7/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, d, fg 0/bg
}
fn psx s: (addr array byte), d: int, fg: int, x: int, y: int {
#? {
#? compare y, 0x60
#? break-if->=
#? return
#? }
#? {
#? compare y, 0x6c
#? break-if-<=
#? return
#? }
{
compare x, 0x20
break-if->=
return
}
#? {
#? compare x, 0x6c
#? break-if-<=
#? return
#? }
draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, s, 7/fg 0/bg
draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, d, fg 0/bg
}
# import a color ascii "pixmap" (each pixel consists of 3 shades of r/g/b from 0 to 255)
fn initialize-image-from-ppm _self: (addr image), in: (addr stream byte) {
var self/esi: (addr image) <- copy _self
var curr-word-storage: slice
var curr-word/ecx: (addr slice) <- address curr-word-storage
# load width, height
next-word-skipping-comments in, curr-word
var tmp/eax: int <- parse-decimal-int-from-slice curr-word
var width/edx: int <- copy tmp
next-word-skipping-comments in, curr-word
tmp <- parse-decimal-int-from-slice curr-word
var height/ebx: int <- copy tmp
next-word-skipping-comments in, curr-word
# check color levels
{
tmp <- parse-decimal-int-from-slice curr-word
compare tmp, 0xff
break-if-=
abort "initialize-image-from-ppm: supports exactly 255 levels per rgb channel"
}
var dest/edi: (addr int) <- get self, max
copy-to *dest, tmp
# save width, height
dest <- get self, width
copy-to *dest, width
dest <- get self, height
copy-to *dest, height
# initialize data
var capacity/edx: int <- copy width
capacity <- multiply height
# . multiply by 3 for the r/g/b channels
var tmp/eax: int <- copy capacity
tmp <- shift-left 1
capacity <- add tmp
#
var data-ah/edi: (addr handle array byte) <- get self, data
populate data-ah, capacity
var _data/eax: (addr array byte) <- lookup *data-ah
var data/edi: (addr array byte) <- copy _data
var i/ebx: int <- copy 0
{
compare i, capacity
break-if->=
next-word-skipping-comments in, curr-word
var src/eax: int <- parse-decimal-int-from-slice curr-word
{
var dest/ecx: (addr byte) <- index data, i
copy-byte-to *dest, src
}
i <- increment
loop
}
}
# import a color ascii "pixmap" (each pixel consists of 3 shades of r/g/b from 0 to 255)
fn render-ppm-image screen: (addr screen), _img: (addr image), xmin: int, ymin: int, width: int, height: int {
var img/esi: (addr image) <- copy _img
# yratio = height/img->height
var img-height-a/eax: (addr int) <- get img, height
var img-height/xmm0: float <- convert *img-height-a
var yratio/xmm1: float <- convert height
yratio <- divide img-height
# xratio = width/img->width
var img-width-a/eax: (addr int) <- get img, width
var img-width/ebx: int <- copy *img-width-a
var img-width-f/xmm0: float <- convert img-width
var xratio/xmm2: float <- convert width
xratio <- divide img-width-f
# esi = img->data
var img-data-ah/eax: (addr handle array byte) <- get img, data
var _img-data/eax: (addr array byte) <- lookup *img-data-ah
var img-data/esi: (addr array byte) <- copy _img-data
var len/edi: int <- length img-data
#
var one/eax: int <- copy 1
var one-f/xmm3: float <- convert one
var width-f/xmm4: float <- convert width
var height-f/xmm5: float <- convert height
var zero/eax: int <- copy 0
var zero-f/xmm0: float <- convert zero
var y/xmm6: float <- copy zero-f
{
compare y, height-f
break-if-float>=
var imgy-f/xmm5: float <- copy y
imgy-f <- divide yratio
var imgy/edx: int <- truncate imgy-f
var x/xmm7: float <- copy zero-f
{
compare x, width-f
break-if-float>=
var imgx-f/xmm5: float <- copy x
imgx-f <- divide xratio
var imgx/ecx: int <- truncate imgx-f
var idx/eax: int <- copy imgy
idx <- multiply img-width
idx <- add imgx
# . multiply by 3 for the r/g/b channels
{
var tmp/ecx: int <- copy idx
tmp <- shift-left 1
idx <- add tmp
}
# error info in case we rounded wrong and 'index' will fail bounds-check
compare idx, len
{
break-if-<
set-cursor-position 0/screen, 0x20/x 0x20/y
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgx, 3/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgy, 4/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, idx, 5/fg 0/bg
}
# r channel
var r: int
{
var src-a/eax: (addr byte) <- index img-data, idx
var src/eax: byte <- copy-byte *src-a
copy-to r, src
}
idx <- increment
# g channel
var g: int
{
var src-a/eax: (addr byte) <- index img-data, idx
var src/eax: byte <- copy-byte *src-a
copy-to g, src
}
idx <- increment
# b channel
var b: int
{
var src-a/eax: (addr byte) <- index img-data, idx
var src/eax: byte <- copy-byte *src-a
copy-to b, src
}
idx <- increment
# plot nearest color
var color/eax: int <- nearest-color-euclidean r, g, b
var screenx/ecx: int <- convert x
screenx <- add xmin
var screeny/edx: int <- convert y
screeny <- add ymin
pixel screen, screenx, screeny, color
x <- add one-f
loop
}
y <- add one-f
loop
}
}
fn dither-ppm-unordered _src: (addr image), _dest: (addr image) {
var src/esi: (addr image) <- copy _src
var dest/edi: (addr image) <- copy _dest
# copy 'width'
var src-width-a/eax: (addr int) <- get src, width
var tmp/eax: int <- copy *src-width-a
var src-width: int
copy-to src-width, tmp
{
var dest-width-a/edx: (addr int) <- get dest, width
copy-to *dest-width-a, tmp
}
# copy 'height'
var src-height-a/eax: (addr int) <- get src, height
var tmp/eax: int <- copy *src-height-a
var src-height: int
copy-to src-height, tmp
{
var dest-height-a/ecx: (addr int) <- get dest, height
copy-to *dest-height-a, tmp
}
# compute scaling factor 255/max
var target-scale/eax: int <- copy 0xff
var scale-f/xmm7: float <- convert target-scale
var src-max-a/eax: (addr int) <- get src, max
var tmp-f/xmm0: float <- convert *src-max-a
scale-f <- divide tmp-f
# allocate 'data'
var capacity/ebx: int <- copy src-width
capacity <- multiply src-height
var dest/edi: (addr image) <- copy _dest
var dest-data-ah/eax: (addr handle array byte) <- get dest, data
populate dest-data-ah, capacity
var _dest-data/eax: (addr array byte) <- lookup *dest-data-ah
var dest-data/edi: (addr array byte) <- copy _dest-data
# error buffers per r/g/b channel
var red-errors-storage: (array int 0xc0000)
var tmp/eax: (addr array int) <- address red-errors-storage
var red-errors: (addr array int)
copy-to red-errors, tmp
var green-errors-storage: (array int 0xc0000)
var tmp/eax: (addr array int) <- address green-errors-storage
var green-errors: (addr array int)
copy-to green-errors, tmp
var blue-errors-storage: (array int 0xc0000)
var tmp/eax: (addr array int) <- address blue-errors-storage
var blue-errors: (addr array int)
copy-to blue-errors, tmp
# transform 'data'
var src-data-ah/eax: (addr handle array byte) <- get src, data
var _src-data/eax: (addr array byte) <- lookup *src-data-ah
var src-data/esi: (addr array byte) <- copy _src-data
var y/edx: int <- copy 0
{
compare y, src-height
break-if->=
var x/ecx: int <- copy 0
{
compare x, src-width
break-if->=
# - update errors and compute color levels for current pixel in each channel
# update red-error with current image pixel
var red-error: int
{
var tmp/esi: int <- _read-dithering-error red-errors, x, y, src-width
copy-to red-error, tmp
}
{
var tmp/eax: int <- _ppm-error src-data, x, y, src-width, 0/red, scale-f
add-to red-error, tmp
}
# recompute red channel for current pixel
var red-level: int
{
var tmp/eax: int <- _error-to-ppm-channel red-error
copy-to red-level, tmp
}
# update green-error with current image pixel
var green-error: int
{
var tmp/esi: int <- _read-dithering-error green-errors, x, y, src-width
copy-to green-error, tmp
}
{
var tmp/eax: int <- _ppm-error src-data, x, y, src-width, 1/green, scale-f
add-to green-error, tmp
}
# recompute green channel for current pixel
var green-level: int
{
var tmp/eax: int <- _error-to-ppm-channel green-error
copy-to green-level, tmp
}
# update blue-error with current image pixel
var blue-error: int
{
var tmp/esi: int <- _read-dithering-error blue-errors, x, y, src-width
copy-to blue-error, tmp
}
{
var tmp/eax: int <- _ppm-error src-data, x, y, src-width, 2/blue, scale-f
add-to blue-error, tmp
}
# recompute blue channel for current pixel
var blue-level: int
{
var tmp/eax: int <- _error-to-ppm-channel blue-error
copy-to blue-level, tmp
}
# - figure out the nearest color
var nearest-color-index/eax: int <- nearest-color-euclidean red-level, green-level, blue-level
{
var nearest-color-index-byte/eax: byte <- copy-byte nearest-color-index
_write-raw-buffer dest-data, x, y, src-width, nearest-color-index-byte
}
# - diffuse errors
var red-level: int
var green-level: int
var blue-level: int
{
var tmp-red-level/ecx: int <- copy 0
var tmp-green-level/edx: int <- copy 0
var tmp-blue-level/ebx: int <- copy 0
tmp-red-level, tmp-green-level, tmp-blue-level <- color-rgb nearest-color-index
copy-to red-level, tmp-red-level
copy-to green-level, tmp-green-level
copy-to blue-level, tmp-blue-level
}
# update red-error
var red-level-error/eax: int <- copy red-level
red-level-error <- shift-left 0x10
subtract-from red-error, red-level-error
_diffuse-dithering-error-floyd-steinberg red-errors, x, y, src-width, src-height, red-error
# update green-error
var green-level-error/eax: int <- copy green-level
green-level-error <- shift-left 0x10
subtract-from green-error, green-level-error
_diffuse-dithering-error-floyd-steinberg green-errors, x, y, src-width, src-height, green-error
# update blue-error
var blue-level-error/eax: int <- copy blue-level
blue-level-error <- shift-left 0x10
subtract-from blue-error, blue-level-error
_diffuse-dithering-error-floyd-steinberg blue-errors, x, y, src-width, src-height, blue-error
#
x <- increment
loop
}
y <- increment
loop
}
}
# convert a single channel for a single image pixel to error space
fn _ppm-error buf: (addr array byte), x: int, y: int, width: int, channel: int, _scale-f: float -> _/eax: int {
# current image pixel
var initial-level/eax: byte <- _read-ppm-buffer buf, x, y, width, channel
# scale to 255 levels
var initial-level-int/eax: int <- copy initial-level
var initial-level-f/xmm0: float <- convert initial-level-int
var scale-f/xmm1: float <- copy _scale-f
initial-level-f <- multiply scale-f
initial-level-int <- convert initial-level-f
# switch to fixed-point with 16 bits of precision
initial-level-int <- shift-left 0x10
return initial-level-int
}
fn _error-to-ppm-channel error: int -> _/eax: int {
# clamp(error >> 16)
var result/esi: int <- copy error
result <- shift-right-signed 0x10
{
compare result, 0
break-if->=
result <- copy 0
}
{
compare result, 0xff
break-if-<=
result <- copy 0xff
}
return result
}
# read from a buffer containing alternating bytes from r/g/b channels
fn _read-ppm-buffer _buf: (addr array byte), x: int, y: int, width: int, channel: int -> _/eax: byte {
var buf/esi: (addr array byte) <- copy _buf
var idx/ecx: int <- copy y
idx <- multiply width
idx <- add x
var byte-idx/edx: int <- copy 3
byte-idx <- multiply idx
byte-idx <- add channel
var result-a/eax: (addr byte) <- index buf, byte-idx
var result/eax: byte <- copy-byte *result-a
return result
}
# each byte in the image data is a color of the current palette
fn render-raw-image screen: (addr screen), _img: (addr image), xmin: int, ymin: int, width: int, height: int {
var img/esi: (addr image) <- copy _img
# yratio = height/img->height
var img-height-a/eax: (addr int) <- get img, height
var img-height/xmm0: float <- convert *img-height-a
var yratio/xmm1: float <- convert height
yratio <- divide img-height
# xratio = width/img->width
var img-width-a/eax: (addr int) <- get img, width
var img-width/ebx: int <- copy *img-width-a
var img-width-f/xmm0: float <- convert img-width
var xratio/xmm2: float <- convert width
xratio <- divide img-width-f
# esi = img->data
var img-data-ah/eax: (addr handle array byte) <- get img, data
var _img-data/eax: (addr array byte) <- lookup *img-data-ah
var img-data/esi: (addr array byte) <- copy _img-data
var len/edi: int <- length img-data
#
var one/eax: int <- copy 1
var one-f/xmm3: float <- convert one
var width-f/xmm4: float <- convert width
var height-f/xmm5: float <- convert height
var zero/eax: int <- copy 0
var zero-f/xmm0: float <- convert zero
var y/xmm6: float <- copy zero-f
{
compare y, height-f
break-if-float>=
var imgy-f/xmm5: float <- copy y
imgy-f <- divide yratio
var imgy/edx: int <- truncate imgy-f
var x/xmm7: float <- copy zero-f
{
compare x, width-f
break-if-float>=
var imgx-f/xmm5: float <- copy x
imgx-f <- divide xratio
var imgx/ecx: int <- truncate imgx-f
var idx/eax: int <- copy imgy
idx <- multiply img-width
idx <- add imgx
# error info in case we rounded wrong and 'index' will fail bounds-check
compare idx, len
{
break-if-<
set-cursor-position 0/screen, 0x20/x 0x20/y
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgx, 3/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, imgy, 4/fg 0/bg
draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, idx, 5/fg 0/bg
}
var color-a/eax: (addr byte) <- index img-data, idx
var color/eax: byte <- copy-byte *color-a
var color-int/eax: int <- copy color
var screenx/ecx: int <- convert x
screenx <- add xmin
var screeny/edx: int <- convert y
screeny <- add ymin
pixel screen, screenx, screeny, color-int
x <- add one-f
loop
}
y <- add one-f
loop
}
}
fn scale-image-height _img: (addr image), width: int -> _/ebx: int {
var img/esi: (addr image) <- copy _img
var img-height/eax: (addr int) <- get img, height
var result-f/xmm0: float <- convert *img-height
var img-width/eax: (addr int) <- get img, width
var img-width-f/xmm1: float <- convert *img-width
result-f <- divide img-width-f
var width-f/xmm1: float <- convert width
result-f <- multiply width-f
var result/ebx: int <- convert result-f
return result
}
fn next-word-skipping-comments line: (addr stream byte), out: (addr slice) {
next-word line, out
var retry?/eax: boolean <- slice-starts-with? out, "#"
compare retry?, 0/false
loop-if-!=
}