[chaoscope] Re: Development update
- From: Zero_G <zero.g80@xxxxxxxxx>
- To: freelists@xxxxxxxxxxxxx
- Date: Tue, 8 Jun 2010 09:05:42 +0200
Dear Nicolas,
these are really good news! I hope the developmente still proceeds in the
right direction, keep up your awesome work!
_____________
.-=[ Zero_G ]=-.
{www.zerog.biz}
On Mon, Jun 7, 2010 at 23:38, Nicolas Desprez <freelists@xxxxxxxxxxxxx>wrote:
> Hi all,
>
> Believe it or not I have been working on Chaoscope for the past few months.
> I've worked on new features that weren't planned but will be part of the new
> release (supersampling, rendering recovery, etc.) and some features that are
> far too experimental to make the cut (ambient occlusion).
>
> Also, at the end of last year I came across a performance related mystery
> while I was comparing rendering time between the development version and the
> current release, 0.3.1.
>
> For the same project, the version in development gave me results varying
> between 7 and 21 million iterations per second. All I was doing was closing
> a project, opening the exact same project again and rendering it. Nothing
> changed in the code between two subsequent renders; the exact same rendering
> path was executed.
>
> To cut a long story short, I finally discovered that the Borland compiler
> didn't necessarily store variables or arrays of type double on an 8 bytes
> aligned address. I don't think this was an issue on old processors but it
> appears to have a massive performance impact on Core Duo models, and
> possibly on more recent models as well.
>
> I do spend an awful amount of time optimising the code and tweaking a line
> here and there to squeeze as much power as I can from the CPU the program is
> running on. So this was a big blow, realising that no matter how much effort
> I'd put into optimisation I'd always be double-guessed by the compiler which
> would find a clever way to make my code run slowly.
>
> Even though I found a solution to this alignment issue (which required
> rewriting large portions of the code) I came to realise that I'd have to
> give up the Borland compiler, at least for the rendering.
>
> So in the beginning of February I eventually decided to port the code to
> generic C++. By generic I mean platform and compiler independent. I
> currently have the rendering part of code compiling on Microsoft, Intel and
> GNU C++ compilers. I took this opportunity to rewrite the code from scratch.
> I also had to code the matrices operations that were handled by OpenGL
> before so that OpenGL support isn't a prerequisite anymore. The code is
> multi-threaded where possible, thanks to OpenMP 2.0.
>
> This was a long and tortuous process that I've only completed recently. The
> result is one multi-threaded DLL and a command line executable that can
> render a project and save an image. The rendering doesn't include
> anti-aliasing yet. So it's far from being the full application.
>
> However, it can be compiled into a 64 bits executable, and most likely on
> Linux and Mac OSX. The other advantage is it will definitely run faster. I
> can't give you precise figures yet because I need to compare apples with
> apples, but I expect the same project to render at least twice as fast with
> the new code.
>
> What's left to do before I can release this is implementing anti-alias,
> multisampling and batch processing. It won't take 4 years, and it won't take
> long beta testing either because the features are so basic.
>
> I wanted to wait until this was ready for public release before announcing
> anything because I've been keeping you guys up to date for the last few
> years and nothing happened yet.
>
> The next step would be to replace the original (Borland compiled) batch
> processing with the new code. Eventually I should have the application split
> between backend/core features (in generic C++) and interface (in Borland,
> then C# later). This would make porting to other platforms much easier.
>
> As far as open-sourcing the project, I want to find out first if there's a
> way to make a living out of it. Obviously I haven't spent enough time or
> energy during the past four years to make this possible but I want to give
> it a go now before I shoot myself in the foot and give months of research
> away. It could be an iPhone, iPad and/or Android application, posters or
> t-shirts sales, a screen saver or advertisement on the site (these last
> three options would work out alongside an open source project). I haven't
> decided yet.
>
> I'd like to take this opportunity to apologise to the forum subscribers
> where I've been more than inactive, and people who've sent me emails I
> haven't replied to yet. I've been dedicating most of my spare time to
> development, and I'm much faster at writing C++ than I am at writing
> English!
>
> Regards,
>
> Nicolas Desprez
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