Messages

1

Graphics / sf::WindowSettings access violation

« on: September 13, 2008, 07:21:57 am »

Yup, that works for me too.  Hurrah!

2

Graphics / sf::WindowSettings access violation

« on: September 11, 2008, 10:49:42 pm »

I get the same problem.  It looks like wglGetProcAddress("wglChoosePixelFormatARB") in WindowImplWin32::CreateContext() returns NULL, so the attempt to use it crashes.  I'm running an NVIDIA GeForce 8800GTX with driver version 175.19 if it matters.

SDL's ChoosePixelFormatARB function creates a (dummy) window, gets the device context, sets the pixel format, creates an OpenGL context, finds the wglGetExtensionsStringARB function, uses that (if found) to get extensions, finds the wglChoosePixelFormatARB function, uses that (if found) to pick a pixel format, releases the OpenGL context, releases the device context, and destroys the window.  Only then does it use that pixel format to create a new window with the appropriate OpenGL context.

From what I've read, those functions require a functioning OpenGL context to work, even if that means you have to create a dummy one first.

3

Feature requests / Clock return in ticks?

« on: January 18, 2008, 03:38:32 am »

Beyond the cost, the precision issue comes up sooner than you'd think.  A single-precision floating-point timer (1 bit sign, 8 bits exponent, 23 bits mantissa) will no longer be capable of millisecond accuracy after about two hours and twenty minutes (2^23 / 1000 seconds).  A 32-bit unsigned millisecond tick timer would wrap around after 49.7 days (2^32 / 1000 seconds), but that's much less likely to be a problem.  (A 64-bit millisecond timer won't wrap around for over half a billion years... )

4

Feature requests / Video mode color buffer alpha

« on: January 18, 2008, 03:18:43 am »

The latter should be okay short-term, but alpha bits is just one of many useful OpenGL setup properties.  SDL exposes a number of them, so there's definitely a call for that sort of thing.  The antialiasing (multisampling) parameter could then be rolled into the larger properties system.

5

Feature requests / Video mode color buffer alpha

« on: January 18, 2008, 02:18:30 am »

I noticed that there's no way to request alpha for the color buffer, even when setting a 32-bit color format.  Some OpenGL blend functions require the color buffer have an alpha channel (e.g. GL_SRC_ALPHA_SATURATE, GL_ONE required by polygon smoothing).  My renderer failedafter switching over from SDL, as the alpha-saturate blending stopped drawing anything due to the missing destination alpha.  I ended up locally modifying WindowImplWin32::CreateContex to request an alpha channel for 32-bit and 16-bit color depths, but that's obviously not ideal.  Exposing the pixel format attributes as some sort of "advanced" properties would help.