Who cares? User-base is more important.

Besides lets be honest, shes probably not a professional game developer (yet) and hence she probably wont need or use all that extra fancy stuff OpenGL lets you do.

And using OpenGL for a smaller project hurts your user-base. For a smaller project like this one user-base is probably more important.

Ha! Thats funny... Really well supported by whose computers?

Most computers support OpenGL. On the other side, some of the OpenGL implemenations are buggy, so programs using OpenGL may not work (display) correctly: My work-in-progress game does not work correctly on my laptop, but everywhere else (where I can test, and some other people can test), so even if OpenGL is supported, you can't always assume that your game will work. The more advanced features and effects of OpenGL you use, the more of potential users may have problems...

D3D is far more supported then OpenGL, which is exactly why I made the Thing Library support D3D.

If you want a bit more solid proof, just look at the early Intel chipsets. Those things are rampant...

Ya now try actually running your app on those Intel driver sets and then tell me how well OpenGL is supported...

Well prepare to be surprised

Screw evidence, not working is evidence enough for me. The earlier* intel chipsets' "support" of OpenGL is buggy at best.
_{* and by earlier I mean very recently.}

Yeah I agree, we're not going to get anywhere. We're just talking on different levels.

Because OpenGL is really portable and generally the code in DX is 6 times longer than in OpenGL - even John Carmarck said this.

In OpenGL you typically do something like this:

glBegin(GL_POLYGON);
  glVertex3f(x1, y1, z1);
  glVertex3f(x2, y2, z2);
  glVertex3f(x3, y3, z3);
  glVertex3f(x4, y4, z4);
glEnd();

Usually preceeded by OGL initialization and opening the window, which is platform dependent - done some way on WinAPI - where actual drawing code is way shorter than that one managing the window. Some other way under xorg etc. Either way, you can even use AllegroGL (which merges Allegro and OGL) and then it's plain simple, you just use one line to open up window.

Anyway if you want really abstract API and high level programming, just grab OpenLayer. It's hardware accelerated addon for Allegro. Its API is really easy.

Paul: for me it was enough to see OpenGL initialization under WinAPI. The things you have to do in order to get window opened resulted in acute headache. Then I showed my "minimalistic" code in AllegroGL which has done the same in just one line of code

D3D isn't like OpenGL. OpenGL has had a version of the same API (i.e. it's evolved, but you can still recognise is) for at least 15 years. Conversely Microsoft make no bones about the fact that they frequently completely redesign significant parts of DirectX. Though I have no direct experience, I believe the D3D interface has become quite a bit nicer with age.

I'm typing this on a Mac but nonetheless I don't think Linux & Mac OpenGL support really amounts to much on a total supported scale.

From memory, Macs were about 5% of sales last December so if we genersously give Mac + Linux say 7% of the market, accept 88.9% as the figure for OpenGL on PC and give Direct3D 95% then total computer Direct3D support is 0.95 * 0.93 = 0.8835, i.e. about 88.35% of all computers. Windows/OpenGL makes 0.889 * 0.93 = 0.8277, i.e. 82.77%.

All Macs since about 1999 have hardware OpenGL, so we'll just call that all Macs. That gives 82.77% + 5% = 87.77% market support for OpenGL. Give hardware OpenGL to 75% of the 2% of the market I arbitrarily gave to Linux and that's another 0.75 * 0.02 = 0.015 = 1.5% of all the computers. Giving OpenGL 87.77 + 1.5 = 89.27% of the market.

It'd be more impressive if I hadn't made the Linux & Direct3d numbers up! But the point is, DirectX is fractionally more supported on Windows. If you account for the entire market, OpenGL may be fractionally more suported. But the differences are tiny.

My OpenGL advocacy arguments would be simply:

• AllegroGL, SDL, OpenLayer all give you a tried and tested OpenGL interface that is popular amongst hobbyist programmers

• OpenGL is not only easy but, on account of its historic API stability, very well documented by free resources

• games are less common on Mac/Linux, so OpenGL may equal more recognition for you due to proportionally fewer competitors

Oh even CAD aplications use OGL.