[C#] Bitmap imaging

[Inquisitor]

I've been playing around with fractal patterns in C# and I've built a program to render the Mandelbrot set, which involves rendering the pattern on a pixel-by-pixel basis (the algorithm i've written does this randomly to produce a nice effect ).

Currently I'm using a Bitmap object and using the method SetPixel() to set the colour of each pixel individually, however this seems to be a very slow way of doing it... is there any better way?

Cheers

 

[Inquisitor]

Well, setting each pixel individually is obviously the only war of doing it, but I was just wondering if there was a more efficient way of doing that than the Bitmap/SetPixel() method.

 

[Inquisitor]

Thanks for the help! Haven't had time to try any of your suggestions out yet... I'll have a look at the LockBits() method I think... seems to require unsafe code though...

In the mean time, have a Mandelbrot image
http://img115.imageshack.us/img115/9400/mandelbrot7zw.png

Still only does monochrome, and looks a bit messy as it's not anti-aliased. Does anyone have any idea how I could anti-alias it?

 

[Inquisitor]

I've tried setting them to 65536, and here is the result:
http://img99.imageshack.us/img99/5715/mandelbrotimage6cx.png

Seems to have helped a bit, but it still looks messy. Also, the higher the iteration count, the darker the image seems to become. I can overcome this by increasing the radiance (which amplifies the brightness of each pixel finding (iterationCount/iterationLimit)^(1 - radiance) * 255). Hower, this seems to reduce the contrast somewhat, especially at very high numbers of iterations.

 

[Inquisitor]

You'd think so, but unless you're doing a stupidly high number of iterations, the time to plot each pixel does actually have a noticeable impact on the overall generation time.

For example, plotting a 300x300 square (of a solid colour) in C# using the method I mentioned, pixel by pixel, takes around 3-5 seconds.

Does PHP feel limiting now?

Well it is only a web scripting language

 

[Inquisitor]

It's certainly very rewarding to get visual results from your hard work
That LockBits method also meant I got to play around with unsafe code /evilgrin

 

[Inquisitor]

By the way, I made a nice 1280x1024 image which is suitable for desktops if anyone wants it

I rendered it at 3840x3840 and then downsampled and cropped it in photoshopped, so it looks fairly nice I've left it monochrome so colour can be added easily (got the colouring working in the renderer as well).

http://img468.imageshack.us/img468/4914/mandelbrot21ha.png

 

[Inquisitor]

Massive improvement - at least 10 times faster
Out of interest, would it be best to lock a 1x1 Rectangle into memory for each pixel, or should I just lock the entire image into memory and keep using the same BitmapData object every time I set a pixel?