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digitalmars.D.announce - GPUFractal-3

reply Burton Radons <burton-radons shaw.ca> writes:
GPUFractal is a silly little macro-mashing program that computes fractals
entirely on a GPU in a single pass with different display options. To run it,
call "gpufractal.exe schema-fractal-cg.h" for the Cg version or "gpufractal.exe
schema-fracta-glsl.h" for the GLSL version. The program requires a recent
powerful graphics card to operate. This is how compatibility seems to be on ATI

	R520 (X1300-X1950) - Should work with a recent driver!
	R420 (X700-X850) - NO. This is new! Does not work, guaranteed! You wouldn't be
able to see anything new anyway. :)
	R300 (9500-9800) - Hah! No way.
	R200, R100, Rage, Mach - Err, no.

The NVIDIA functionality seems to be:

	GeForce 8 - Yayyay!
	GeForce 7 - Yay!
	GeForce 6 - Yes! I don't know if it can handle Orbit Traps.
	GeForce 2-5/256, Riva 128/TNT/TNT2, NV1/NV2 - Not likely.
	ASR-33 Teletype - Lacks a processor.

If it's not on this list, the answer is likely "no". If it seems like it should
work but it doesn't, your driver is probably years out of date. The current ATI
driver reports version "2.0.6956" on the command line. The current NVIDIA
driver reports version "2.1.1".

http://members.shaw.ca/burton-radons/GPUFractal-3.7z (executable, 271KB)
http://members.shaw.ca/burton-radons/GPUFractal-3-source.7z (source, 303KB)
http://members.shaw.ca/burton-radons/cg.7z (Cg DLLs if you need them, 627KB)

The interface is exclusively mouse based. Left mouse button to zoom in, right
mouse button to zoom out, middle mouse button to scroll. Using the mouse wheel
puts you in variable mode. The mouse wheel selects the current variable,
dragging the left mouse button changes it (enumerations and floats are changed
by dragging to the right or left), clicking the middle mouse button resets to
the initial value, and right clicking returns to zoom/scroll mode.

I didn't want to make a new version but looking over it, so many things are
different that it's a substantively changed program internally. Here are the

- R420 support has been completely dropped for now.

- Added multisampling global parameter. This has no effect on hardware (such as
my ATI X850) where the anti-aliasing is restricted to polygon edges, and only
has an effect at 16 and 32 on the NVIDIA 8800, but I don't think I have any
mechanism to detect this through an API. I chose to directly destroy and
recreate the main window, which is probably not much slower than keeping the
rendering in a sub-window, and much simpler to do. Hooray for list sharing!

- Switched to string-based enums a la Ultra Fractal, renamed cfloat to complex
for the same reason. Added heading, colour, and function parameters. Changed
how gradients are indexed, fixed aspect ratio, and other tweaks to bring the
display and processing closer to Ultra Fractal.

- Unified parameters; formula selections are now just parameters, and formulas
can be parameters to formulas. Boy howdy was this a big change!

- Added language parameter to formulas. If the language doesn't match the
schema language, I attempt to convert it. Naturally the first added language is
UltraFractal, which is exactly one bazillion times better at dealing with
complex values than Cg or GLSL. This allowed me to dump in the 618-line Orbit
Traps mostly unmodified, whereas it would have taken me one or two days to
convert it by hand certainly with bugs.

- Added outside formula Triangle Inequality Average. The defaults are set for
Mandelbrot; for Julia set the bailout to about 7.84 with default power (2, 0).
Then bring the seed to be just on the edge of breaking out into inside regions
for some neat effects.

- Added outside formula Orbit Traps which is incredibly complex and a great
test of the UltraFractal parser and Cg/GLSL generator. There is no hope at all
of this working if your card has any limitations. Cg does NOT like Orbit Traps,
producing terrible code; use GLSL instead.

- Got rid of some spurious warnings from Cg.
Oct 22 2007
next sibling parent Burton Radons <burton-radons shaw.ca> writes:
Updated to make the ATI R420 work, as well as various fixes and tweaks.
Aaaand... that's it! I'm never updating this again!

If anyone's interested, all the source code is public domain. The files within
the fractal subdirectory, however, are not, and shouldn't be used in any
derivative works or future versions, if any.
Oct 23 2007
prev sibling parent Burton Radons <burton-radons shaw.ca> writes:
More fuel for the Cg vs GLSL debate: I sent the link to the creator of Ultra
Fractal and he asked about calculation speed, so I told the program to redraw
as fast as possible and turned off vsync in the control panel. A 1024x768
image, Smooth outside and None inside, runs at 82 FPS under Cg on this machine
- an NVIDIA 8800 GTX with a 2.66 GHz Intel Dual Core processor on Windows
Vista, everything up to date. Under GLSL, the same image runs at 131 FPS, 59%
faster. I think it's safe to say that GLSL has eclipsed Cg when doing hardcore
numbers of operations on NVIDIA hardware, and even so I know the GLSL optimiser
is pretty poor.
Oct 23 2007