Where it all began

2022-03-19T15:19:22+00:00

Writing a raytracer was a school homework excersise back in 2007. For this project I didn’t use source control so I don’t have history data. I think it was a one source file project when I submitted it.

In 2008 improvements were made and I split the code into more source files. In 2013 I imported them to git. This version had some issues:

it contained an unfinished Kd-Tree implementation,
there was a lot of dead code,
it was very slow.

Let’s see some metrics. To get this initial code df76ccf link I needed to modify the Makefile like this:

@@ -39,7 +39,7 @@ $(BUILDDIR)/%.o: %.cc
 -include $(ray_OBJS:%.o=$(DEPDIR)/%.d)

 ray: $(ray_OBJS:%.o=$(BUILDDIR)/%.o)
-       @$(CC) $(LDFLAGS) -o $@ $^
+       @$(CC) $^ $(LDFLAGS) -o $@
        @echo "  LN    $@"

 clean:

Using gcc-10.2.1 it compiles to a 56936 byte x86_64 executable on linux. This is the unstripped size.

$ size ray
   text	   data	    bss	    dec	    hex	filename
  35323	   2056	    624	  38003	   9473	ray

The program needs about 14 seconds on my machine to render the 1280x800 output image:

$ time ./ray
62.60% Output has been written to tracement.tga
94.40% Output has been written to tracement.tga
freeNode(0)
./ray  52.22s user 0.06s system 372% cpu 14.026 total

Here is the result rendering:

So that’s where I started from.

The initial goal was to see if I can speed the thing up.

Size-optimizing my old toy-raytracer

Where it all began