Mini ray tracer - comp.graphics.rendering.raytracing

Message from discussion Mini ray tracer

tbp...@gmail.com

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More options 9 May 2005, 18:51

Newsgroups: comp.graphics.rendering.raytracing

From: tbp...@gmail.com

Date: 9 May 2005 10:51:28 -0700

Local: Mon 9 May 2005 18:51

Subject: Re: Mini ray tracer

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Jon Harrop wrote:
> I then cut this program down to a 66-line OCaml program and ported it
into a
> 97-line C++ program. These programs are compared on this page:

> http://www.ffconsultancy.com/free/ray_tracer/comparison.html

Is that comparison supposed to be fair in any way whatsoever?

Somewhere on an opteron 146 running debian64:
# g++ -g -O3 ray.cpp -o ray
# time ./ray >tt

real 0m13.959s
user 0m13.946s
sys 0m0.009s

# objdump -x ray
[2mn later]
# diff ray_orig.cpp ray.cpp
12,16c12,18
< Vec operator+(Vec a, Vec b) { return Vec(a.x + b.x, a.y + b.y, a.z +
b.z); }
< Vec operator-(Vec a, Vec b) { return Vec(a.x - b.x, a.y - b.y, a.z -
b.z); }
< Vec operator*(double a, Vec b) { return Vec(a * b.x, a * b.y, a *
b.z); }
< double dot(Vec a, Vec b) { return a.x*b.x + a.y*b.y + a.z*b.z; }
< Vec unitise(Vec a) { return (1 / sqrt(dot(a, a))) * a; }
---

> inline Vec operator+(const Vec &a, const Vec &b) { return Vec(a.x +

b.x, a.y + b.y, a.z + b.z); }

> inline Vec operator-(const Vec &a, const Vec &b) { return Vec(a.x -

b.x, a.y - b.y, a.z - b.z); }

> inline Vec operator*(const double a, const Vec &b) { return Vec(a *

b.x, a * b.y, a * b.z); }

> inline double dot(const Vec &a, const Vec &b) { return a.x*b.x +

a.y*b.y + a.z*b.z; }

> inline Vec unitise(const Vec &a) { return (1 / sqrt(dot(a, a))) * a;
}

# g++ -g -O3 ray.cpp -o ray
# time ./ray >tt

real 0m10.493s
user 0m10.483s
sys 0m0.005s

If your point was to show how to write unbelievably inneficient code in
C++, you've succeeded.
Can't wait for a C++ vs Java comparison.

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