4 files changed, 154 insertions, 3 deletions

diff --git a/408print-float.mu b/408print-float.mu
index d1782044..67e46f03 100644
--- a/408print-float.mu
+++ b/408print-float.mu
@@ -8,7 +8,7 @@
 #                          mantissa                  exponent
 #                    = 0 | 000000000000000000000000 | 01111110
 #                          zero-pad mantissa          exponent
-#                   =   +1.000000                   p -01
+#                   =   +1.000000                   P -01
 fn test-print-float-normal {
   var screen-on-stack: screen
   var screen/esi: (addr screen) <- address screen-on-stack
@@ -21,7 +21,7 @@ fn test-print-float-normal {
   half <- divide two-f
   print-float screen, half
   #
-  check-screen-row screen, 1, "1.000000p-01 ", "F - test-print-float-normal"
+  check-screen-row screen, 1, "1.000000P-01 ", "F - test-print-float-normal"
 }
 
 fn test-print-float-zero {
@@ -150,7 +150,7 @@ $print-float:body: {
   mantissa <- and 0x7fffff
   print-int32-hex-bits screen, mantissa, 0x18
   # print exponent
-  print-string screen, "p"
+  print-string screen, "P"
   exponent <- subtract 0x7f
   compare exponent, 0
   {
diff --git a/apps/raytracing/3.mu b/apps/raytracing/3.mu
new file mode 100644
index 00000000..6be820f6
--- /dev/null
+++ b/apps/raytracing/3.mu
@@ -0,0 +1,127 @@
+# Listing 7 of https://raytracing.github.io/books/RayTracingInOneWeekend.html
+#
+# To run (on Linux):
+#   $ git clone https://github.com/akkartik/mu
+#   $ cd mu
+#   $ ./translate_mu apps/raytracing/3.mu
+#   $ ./a.elf > 3.ppm
+
+fn main -> exit-status/ebx: int {
+  print-string 0, "P3\n256 256\n255\n"
+  var _four/edx: int <- copy 4
+  var four/xmm1: float <- convert _four
+  var one-fourth/xmm1: float <- reciprocal four
+  var max/edx: int <- copy 0xff
+  var image-size/xmm2: float <- convert max
+  var j/ecx: int <- copy 0xff
+  {
+    compare j, 0
+    break-if-<
+    var i/eax: int <- copy 0
+    {
+      compare i, 0xff
+      break-if->
+#?       var c: rgb
+#?       # compute r
+#?       var tmp/xmm0: float <- convert i
+#?       tmp <- divide image-size
+#?       var r-addr/edx: (addr float) <- get c, r
+#?       copy-to *r-addr, tmp
+#? #?       var tmp2/ebx: int <- reinterpret *r-addr
+#? #?       print-int32-hex 0, tmp2
+#? #?       print-string 0, "\n"
+#?       # compute g
+#?       tmp <- convert j
+#?       tmp <- divide image-size
+#?       var g-addr/edx: (addr float) <- get c, g
+#?       copy-to *g-addr, tmp
+#?       # compute b
+#?       var b-addr/edx: (addr float) <- get c, b
+#?       copy-to *b-addr, one-fourth
+#?       # emit
+#?       var c-addr/edx: (addr rgb) <- address c
+#?       print-rgb 0, c-addr
+      var p: vec3
+      # compute r
+      var tmp/xmm0: float <- convert i
+      tmp <- divide image-size
+      var r-addr/edx: (addr float) <- get p, x
+      copy-to *r-addr, tmp
+#?       var tmp2/ebx: int <- reinterpret *r-addr
+#?       print-int32-hex 0, tmp2
+#?       print-string 0, "\n"
+      # compute g
+      tmp <- convert j
+      tmp <- divide image-size
+      var g-addr/edx: (addr float) <- get p, y
+      copy-to *g-addr, tmp
+      # compute b
+      var b-addr/edx: (addr float) <- get p, z
+      copy-to *b-addr, one-fourth
+      # emit
+      var p-addr/edx: (addr vec3) <- address p
+      print-vec3 0, p-addr
+      print-string 0, "\n"
+      i <- increment
+      loop
+    }
+    j <- decrement
+    loop
+  }
+  exit-status <- copy 1
+}
+
+type rgb {
+  # components normalized to within [0.0, 1.0]
+  r: float
+  g: float
+  b: float
+}
+
+# print translating to [0, 256)
+fn print-rgb screen: (addr screen), _c: (addr rgb) {
+  var c/esi: (addr rgb) <- copy _c
+  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
+  var xn/xmm1: float <- convert n
+  # print 255 * c->r
+  var result/xmm0: float <- copy xn
+  var src-addr/eax: (addr float) <- get c, r
+  result <- multiply *src-addr
+  var result-int/edx: int <- convert result
+  print-int32-decimal screen, result-int
+  print-string screen, " "
+  # print 255 * c->g
+  src-addr <- get c, g
+  result <- copy xn
+  result <- multiply *src-addr
+  result-int <- convert result
+  print-int32-decimal screen, result-int
+  print-string screen, " "
+  # print 255 * c->b
+  src-addr <- get c, b
+  result <- copy xn
+  result <- multiply *src-addr
+  result-int <- convert result
+  print-int32-decimal screen, result-int
+  print-string screen, "\n"
+}
+
+type vec3 {
+  x: float
+  y: float
+  z: float
+}
+
+fn print-vec3 screen: (addr screen), _a: (addr vec3) {
+  var a/esi: (addr vec3) <- copy _a
+  print-string screen, "("
+  var tmp/eax: (addr float) <- get a, x
+  print-float screen, *tmp
+  print-string screen, ", "
+  tmp <- get a, y
+  print-float screen, *tmp
+  print-string screen, ", "
+  tmp <- get a, z
+  print-float screen, *tmp
+  print-string screen, ")"
+}
diff --git a/apps/raytracing/ray.mu b/apps/raytracing/ray.mu
new file mode 100644
index 00000000..ca2cb475
--- /dev/null
+++ b/apps/raytracing/ray.mu
@@ -0,0 +1,13 @@
+type ray {
+  orig: vec3  # point
+  dir: vec3
+}
+
+fn ray-at _self: (addr ray), t: float, out: (addr vec3) {
+  var self/esi: (addr ray) <- copy _self
+  var src/eax: (addr vec3) <- get self, dir
+  copy-object src, out
+  vec3-mul-by out, t
+  src <- get self, orig
+  vec3-add-to out, src
+}
diff --git a/apps/raytracing/vec.mu b/apps/raytracing/vec.mu
index 29516fb1..5539a0dd 100644
--- a/apps/raytracing/vec.mu
+++ b/apps/raytracing/vec.mu
@@ -35,4 +35,15 @@ fn vec3-unit in: (addr vec3), out: (addr vec3) {
 }
 
 fn print-vec3 screen: (addr screen), _a: (addr vec3) {
+  var a/esi: (addr vec3) <- copy _a
+  print-string screen, "("
+  var tmp/eax: (addr float) <- get a, x
+  print-float screen, *tmp
+  print-string screen, ", "
+  tmp <- get a, y
+  print-float screen, *tmp
+  print-string screen, ", "
+  tmp <- get a, z
+  print-float screen, *tmp
+  print-string screen, ")"
 }