485 lines
13 KiB
Forth
485 lines
13 KiB
Forth
# Listing 9 of https://raytracing.github.io/books/RayTracingInOneWeekend.html
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#
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# To run (on Linux):
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# $ git clone https://github.com/akkartik/mu
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# $ cd mu/linux
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# $ ./translate apps/raytracing/3.mu
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# $ ./a.elf > 3.ppm
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fn ray-color _in: (addr ray), _out: (addr rgb) {
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var in/esi: (addr ray) <- copy _in
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var out/edi: (addr rgb) <- copy _out
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var dir/eax: (addr vec3) <- get in, dir
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#? print-string 0, "r.dir: "
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#? print-vec3 0, dir
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#? print-string 0, "\n"
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var unit-storage: vec3
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var unit/ecx: (addr vec3) <- address unit-storage
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vec3-unit dir, unit
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#? print-string 0, "r.dir normalized: "
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#? print-vec3 0, unit
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#? print-string 0, "\n"
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var y-addr/eax: (addr float) <- get unit, y
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# t = (dir.y + 1.0) / 2.0
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var t/xmm0: float <- copy *y-addr
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var one/eax: int <- copy 1
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var one-f/xmm1: float <- convert one
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t <- add one-f
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var two/eax: int <- copy 2
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var two-f/xmm2: float <- convert two
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t <- divide two-f
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#? print-string 0, "t: "
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#? print-float-hex 0, t
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#? print-string 0, "\n"
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# whitening = (1.0 - t) * white
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var whitening-storage: rgb
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var whitening/ecx: (addr rgb) <- address whitening-storage
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rgb-white whitening
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var one-minus-t/xmm3: float <- copy one-f
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one-minus-t <- subtract t
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rgb-scale-up whitening, one-minus-t
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#? print-string 0, "whitening: "
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#? print-rgb-raw 0, whitening
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#? print-string 0, "\n"
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# out = t * (0.5, 0.7, 1.0)
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var dest/eax: (addr float) <- get out, r
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fill-in-rational dest, 5, 0xa
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dest <- get out, g
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fill-in-rational dest, 7, 0xa
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dest <- get out, b
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copy-to *dest, one-f
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rgb-scale-up out, t
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#? print-string 0, "base: "
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#? print-rgb-raw 0, out
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#? print-string 0, "\n"
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# blend with whitening
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rgb-add-to out, whitening
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#? print-string 0, "result: "
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#? print-rgb-raw 0, out
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#? print-string 0, "\n"
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}
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fn main -> _/ebx: int {
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# image
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# width = 400
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# height = 400 * 9/16 = 225
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var aspect: float
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var aspect-addr/eax: (addr float) <- address aspect
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fill-in-rational aspect-addr, 0x10, 9 # 16/9
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#? print-string 0, "aspect ratio: "
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#? print-float-hex 0, aspect
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#? print-string 0, " "
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#? {
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#? var foo2/ebx: int <- reinterpret aspect
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#? print-int32-hex 0, foo2
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#? }
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#? print-string 0, "\n"
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# camera
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# viewport-height = 2.0
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var tmp/eax: int <- copy 2
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var two-f/xmm4: float <- convert tmp
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var viewport-height/xmm7: float <- copy two-f
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#? print-string 0, "viewport height: "
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#? print-float-hex 0, viewport-height
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#? print-string 0, " "
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#? {
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#? var foo: float
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#? copy-to foo, viewport-height
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#? var foo2/ebx: int <- reinterpret foo
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#? print-int32-hex 0, foo2
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#? }
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#? print-string 0, "\n"
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# viewport-width = aspect * viewport-height
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var viewport-width/xmm6: float <- convert tmp
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viewport-width <- multiply aspect
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#? print-string 0, "viewport width: "
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#? print-float-hex 0, viewport-width
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#? print-string 0, " "
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#? {
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#? var foo: float
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#? copy-to foo, viewport-width
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#? var foo2/ebx: int <- reinterpret foo
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#? print-int32-hex 0, foo2
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#? }
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#? print-string 0, "\n"
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# focal-length = 1.0
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tmp <- copy 1
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var focal-length/xmm5: float <- convert tmp
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# origin = point3(0, 0, 0)
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var origin-storage: vec3
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var origin/edi: (addr vec3) <- address origin-storage
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# horizontal = vec3(viewport-width, 0, 0)
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var horizontal-storage: vec3
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var dest/eax: (addr float) <- get horizontal-storage, x
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copy-to *dest, viewport-width
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var horizontal/ebx: (addr vec3) <- address horizontal-storage
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# vertical = vec3(0, viewport-height, 0)
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var vertical-storage: vec3
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dest <- get vertical-storage, y
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copy-to *dest, viewport-height
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var vertical/edx: (addr vec3) <- address vertical-storage
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# lower-left-corner = origin - horizontal/2 - vertical/2 - vec3(0, 0, focal-length)
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# . lower-left-corner = origin
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var lower-left-corner-storage: vec3
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var lower-left-corner/esi: (addr vec3) <- address lower-left-corner-storage
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copy-object origin, lower-left-corner
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# . lower-left-corner -= horizontal/2
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var tmp2: vec3
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var tmp2-addr/eax: (addr vec3) <- address tmp2
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copy-object horizontal, tmp2-addr
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vec3-scale-down tmp2-addr, two-f
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vec3-subtract-from lower-left-corner, tmp2-addr
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# . lower-left-corner -= vertical/2
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copy-object vertical, tmp2-addr
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vec3-scale-down tmp2-addr, two-f
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vec3-subtract-from lower-left-corner, tmp2-addr
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# . lower-left-corner -= vec3(0, 0, focal-length)
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var dest2/ecx: (addr float) <- get lower-left-corner, z
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var tmp3/xmm0: float <- copy *dest2
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tmp3 <- subtract focal-length
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copy-to *dest2, tmp3
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# phew!
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# render
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# live variables at this point:
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# origin (edi)
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# lower-left-corner (esi)
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# horizontal (ebx)
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# vertical (edx)
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# floating-point registers are all free
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print-string 0, "P3\n400 225\n255\n" # 225 = image height
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var tmp/eax: int <- copy 0x18f # image width - 1
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var image-width-1/xmm7: float <- convert tmp
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tmp <- copy 0xe0 # image height - 1
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var image-height-1/xmm6: float <- convert tmp
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#
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var j/ecx: int <- copy 0xe0 # 224
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{
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compare j, 0
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break-if-<
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var i/eax: int <- copy 0
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{
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compare i, 0x190 # 400 = image width
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break-if->=
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# u = i / (image-width - 1)
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var u/xmm0: float <- convert i
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u <- divide image-width-1
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#? print-string 0, "u: "
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#? print-float-hex 0, u
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#? print-string 0, "\n"
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# v = j / (image-height - 1)
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var v/xmm1: float <- convert j
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v <- divide image-height-1
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# r = ray(origin, lower-left-corner + u*horizontal + v*vertical - origin)
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var r-storage: ray
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# . . we're running out of int registers now,
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# . . but luckily we don't need i and j in the rest of this loop iteration,
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# . . so we'll just spill them in a block
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{
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# . r.orig = origin
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var r/eax: (addr ray) <- address r-storage
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var dest/ecx: (addr vec3) <- get r, orig
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copy-object origin, dest
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# . r.dir = lower-left-corner
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dest <- get r, dir
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copy-object lower-left-corner, dest
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# . r.dir += horizontal*u
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var tmp-vec3: vec3
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var tmp/eax: (addr vec3) <- address tmp-vec3
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copy-object horizontal, tmp
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vec3-scale-up tmp, u
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vec3-add-to dest, tmp
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# . r.dir += vertical*v
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copy-object vertical, tmp
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vec3-scale-up tmp, v
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vec3-add-to dest, tmp
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# . r.dir -= origin
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vec3-subtract-from dest, origin
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#? print-string 0, "ray direction: "
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#? print-vec3 0, dest
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#? print-string 0, "\n"
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}
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# pixel-color = ray-color(r)
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var c-storage: rgb
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var c/ecx: (addr rgb) <- address c-storage
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{
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var r/eax: (addr ray) <- address r-storage
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ray-color r, c
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# write color
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print-rgb 0, c
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#? print-rgb-raw 0, c
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#? print-string 0, "\n"
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}
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i <- increment
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loop
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}
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j <- decrement
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loop
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}
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return 0
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}
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type ray {
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orig: vec3 # point
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dir: vec3
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}
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# A little different from the constructor at https://raytracing.github.io/books/RayTracingInOneWeekend.html
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# We immediately normalize the direction vector so we don't have to keep doing
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# so.
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fn initialize-ray _self: (addr ray), o: (addr vec3), d: (addr vec3) {
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var self/esi: (addr ray) <- copy _self
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var dest/eax: (addr vec3) <- get self, orig
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copy-object o, dest
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dest <- get self, dir
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vec3-unit d, dest
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}
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fn ray-at _self: (addr ray), t: float, out: (addr vec3) {
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var self/esi: (addr ray) <- copy _self
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var src/eax: (addr vec3) <- get self, dir
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copy-object src, out
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vec3-scale-up out, t
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src <- get self, orig
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vec3-add-to out, src
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}
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type rgb {
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# components normalized to within [0.0, 1.0]
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r: float
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g: float
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b: float
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}
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# print translating to [0, 256)
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fn print-rgb screen: (addr screen), _c: (addr rgb) {
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var c/esi: (addr rgb) <- copy _c
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var xn: float
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var xn-addr/ecx: (addr float) <- address xn
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fill-in-rational xn-addr, 0x3e7ff, 0x3e8 # 255999 / 1000
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# print 255.999 * c->r
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var result/xmm0: float <- copy xn
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var src-addr/eax: (addr float) <- get c, r
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result <- multiply *src-addr
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var result-int/edx: int <- truncate result
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print-int32-decimal screen, result-int
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print-string screen, " "
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# print 255.999 * c->g
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src-addr <- get c, g
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result <- copy xn
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result <- multiply *src-addr
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result-int <- truncate result
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print-int32-decimal screen, result-int
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print-string screen, " "
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# print 255.999 * c->b
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src-addr <- get c, b
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result <- copy xn
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result <- multiply *src-addr
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result-int <- truncate result
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print-int32-decimal screen, result-int
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print-string screen, "\n"
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}
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fn print-rgb-raw screen: (addr screen), _v: (addr rgb) {
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var v/esi: (addr rgb) <- copy _v
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print-string screen, "("
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var tmp/eax: (addr float) <- get v, r
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print-float-hex screen, *tmp
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print-string screen, ", "
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tmp <- get v, g
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print-float-hex screen, *tmp
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print-string screen, ", "
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tmp <- get v, b
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print-float-hex screen, *tmp
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print-string screen, ")"
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}
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fn rgb-white _c: (addr rgb) {
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var c/esi: (addr rgb) <- copy _c
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var one/eax: int <- copy 1
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var one-f/xmm0: float <- convert one
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var dest/edi: (addr float) <- get c, r
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copy-to *dest, one-f
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dest <- get c, g
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copy-to *dest, one-f
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dest <- get c, b
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copy-to *dest, one-f
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}
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fn rgb-add-to _c1: (addr rgb), _c2: (addr rgb) {
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var c1/edi: (addr rgb) <- copy _c1
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var c2/esi: (addr rgb) <- copy _c2
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# c1.r += c2.r
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var arg1/eax: (addr float) <- get c1, r
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var arg2/ecx: (addr float) <- get c2, r
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var result/xmm0: float <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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# c1.g += c2.g
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arg1 <- get c1, g
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arg2 <- get c2, g
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result <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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# c1.b += c2.b
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arg1 <- get c1, b
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arg2 <- get c2, b
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result <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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}
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fn rgb-scale-up _c1: (addr rgb), f: float {
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var c1/edi: (addr rgb) <- copy _c1
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# c1.r *= f
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var dest/eax: (addr float) <- get c1, r
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var result/xmm0: float <- copy *dest
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result <- multiply f
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copy-to *dest, result
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# c1.g *= f
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dest <- get c1, g
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result <- copy *dest
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result <- multiply f
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copy-to *dest, result
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# c1.b *= f
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dest <- get c1, b
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result <- copy *dest
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result <- multiply f
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copy-to *dest, result
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}
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type vec3 {
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x: float
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y: float
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z: float
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}
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fn print-vec3 screen: (addr screen), _v: (addr vec3) {
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var v/esi: (addr vec3) <- copy _v
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print-string screen, "("
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var tmp/eax: (addr float) <- get v, x
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print-float-hex screen, *tmp
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print-string screen, ", "
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tmp <- get v, y
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print-float-hex screen, *tmp
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print-string screen, ", "
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tmp <- get v, z
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print-float-hex screen, *tmp
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print-string screen, ")"
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}
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fn vec3-add-to _v1: (addr vec3), _v2: (addr vec3) {
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var v1/edi: (addr vec3) <- copy _v1
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var v2/esi: (addr vec3) <- copy _v2
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# v1.x += v2.x
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var arg1/eax: (addr float) <- get v1, x
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var arg2/ecx: (addr float) <- get v2, x
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var result/xmm0: float <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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# v1.y += v2.y
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arg1 <- get v1, y
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arg2 <- get v2, y
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result <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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# v1.z += v2.z
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arg1 <- get v1, z
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arg2 <- get v2, z
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result <- copy *arg1
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result <- add *arg2
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copy-to *arg1, result
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}
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fn vec3-subtract-from v1: (addr vec3), v2: (addr vec3) {
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var tmp-storage: vec3
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var tmp/eax: (addr vec3) <- address tmp-storage
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copy-object v2, tmp
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vec3-negate tmp
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vec3-add-to v1, tmp
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}
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fn vec3-negate v: (addr vec3) {
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var negative-one/eax: int <- copy -1
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var negative-one-f/xmm0: float <- convert negative-one
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vec3-scale-up v, negative-one-f
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}
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fn vec3-scale-up _v: (addr vec3), f: float {
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var v/edi: (addr vec3) <- copy _v
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# v.x *= f
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var dest/eax: (addr float) <- get v, x
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var result/xmm0: float <- copy *dest
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result <- multiply f
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copy-to *dest, result
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# v.y *= f
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dest <- get v, y
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result <- copy *dest
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result <- multiply f
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copy-to *dest, result
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# v.z *= f
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dest <- get v, z
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result <- copy *dest
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result <- multiply f
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copy-to *dest, result
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}
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fn vec3-scale-down _v: (addr vec3), f: float {
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var v/edi: (addr vec3) <- copy _v
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# v.x /= f
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var dest/eax: (addr float) <- get v, x
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var result/xmm0: float <- copy *dest
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result <- divide f
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copy-to *dest, result
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# v.y /= f
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dest <- get v, y
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result <- copy *dest
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result <- divide f
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copy-to *dest, result
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# v.z /= f
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dest <- get v, z
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result <- copy *dest
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result <- divide f
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copy-to *dest, result
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}
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fn vec3-unit in: (addr vec3), out: (addr vec3) {
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var len/xmm0: float <- vec3-length in
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#? print-string 0, "len: "
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#? print-float-hex 0, len
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#? print-string 0, "\n"
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copy-object in, out
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vec3-scale-down out, len
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}
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fn vec3-length v: (addr vec3) -> _/xmm0: float {
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var result/xmm0: float <- vec3-length-squared v
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result <- square-root result
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return result
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}
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fn vec3-length-squared _v: (addr vec3) -> _/xmm0: float {
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var v/esi: (addr vec3) <- copy _v
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# result = v.x * v.x
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var src/eax: (addr float) <- get v, x
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var tmp/xmm1: float <- copy *src
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tmp <- multiply tmp
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var result/xmm0: float <- copy tmp
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# result += v.y * v.y
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src <- get v, y
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tmp <- copy *src
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tmp <- multiply tmp
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result <- add tmp
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# result += v.z * v.z
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src <- get v, z
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tmp <- copy *src
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tmp <- multiply tmp
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result <- add tmp
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return result
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}
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