Geoff Levner wrote: > Larry Hall (Cygwin X) wrote: >> Geoff Levner wrote: >> >>> I have an OpenGL-based application executing on a Sun, but displaying >>> on a PC running Windows XP and an X server. The app requires a >>> TrueColor visual, so when it calls glXChooseVisual, it passes >>> GLX_RGBA in the attribute list. This works fine with another X server >>> (Exceed), but when using Cygwin/X, glXChooseVisual fails to return a >>> visual. >>> >>> Running xdpyinfo would seem to indicate that the server has *only* >>> TrueColor visuals (see the output below). And in fact if I remove >>> GLX_RGBA from the attribute list, glXChooseVisual does return one of >>> those visuals. If I ask for information about the visual with >>> glXGetConfig, it responds that color buffers store color indices >>> (GLX_RGBA is false), yet the application works correctly. >>> >>> Anybody have a clue what is going on here? >>> >> >> >> Looks to me like you're app is looking for 32 bits while Cygwin-X is >> only providing 24 bits. Unless you know you absolutely need >> transparency, I think you'll find everything works fine with the >> visuals you can get. Just ask for GLX_RGB instead. >> >> > That sounds reasonable, but GLX_RGB is not defined, and I can't find any > reference to it in the GLX 1.4 specifications. According to the > documentation, GLX_RGBA just means you want TrueColor or DirectColor > visuals; it says nothing about alpha. And we do not ask for any alpha > bits...
Yup, you're right. I was thinking of something else. Perhaps it's just your combination of attributes. You might check that. The combination below has worked for me before, albeit from a Linux machine to Cygwin/X: int visual_attributes[] = { GLX_DOUBLEBUFFER, GLX_RGBA, GLX_RED_SIZE, 1, GLX_GREEN_SIZE, 1, GLX_BLUE_SIZE, 1, GLX_DEPTH_SIZE, 1, GLX_STENCIL_SIZE, 1, GLX_ACCUM_RED_SIZE, 1, GLX_ACCUM_GREEN_SIZE, 1, GLX_ACCUM_BLUE_SIZE, 1, None }; -- Larry Hall http://www.rfk.com RFK Partners, Inc. (508) 893-9779 - RFK Office 216 Dalton Rd. (508) 893-9889 - FAX Holliston, MA 01746 -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/