87 lines
2.3 KiB
Forth
87 lines
2.3 KiB
Forth
# Listing 7 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
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# $ ./translate raytracing/2.mu
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# $ ./a.elf > 2.ppm
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fn main -> _/ebx: int {
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print-string 0, "P3\n256 256\n255\n"
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var _four/edx: int <- copy 4
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var four/xmm1: float <- convert _four
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var one-fourth/xmm1: float <- reciprocal four
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var max/edx: int <- copy 0xff
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var image-size/xmm2: float <- convert max
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var j/ecx: int <- copy 0xff
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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, 0xff
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break-if->
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var c: rgb
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# compute r
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var tmp/xmm0: float <- convert i
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tmp <- divide image-size
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var r-addr/edx: (addr float) <- get c, r
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copy-to *r-addr, tmp
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#? var tmp2/ebx: int <- reinterpret *r-addr
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#? print-int32-hex 0, tmp2
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#? print-string 0, "\n"
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# compute g
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tmp <- convert j
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tmp <- divide image-size
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var g-addr/edx: (addr float) <- get c, g
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copy-to *g-addr, tmp
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# compute b
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var b-addr/edx: (addr float) <- get c, b
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copy-to *b-addr, one-fourth
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# emit
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var c-addr/edx: (addr rgb) <- address c
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print-rgb 0, c-addr
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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 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 n/ecx: int <- copy 0xff # turns out 255 works just as well as 255.999, which is lucky because we don't have floating-point literals
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var xn/xmm1: float <- convert n
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# print 255 * 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 <- convert result
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print-int32-decimal screen, result-int
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print-string screen, " "
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# print 255 * 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 <- convert result
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print-int32-decimal screen, result-int
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print-string screen, " "
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# print 255 * 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 <- convert 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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