Stencil Buffer Problem

OpenGL OpenGL: Advanced Coding
1

Hi, I have a Problem with the stencil buffer. I request a 8Bit stencil buffer (PIXELDATAFORMAT) in Win2k. In window mode, the stencil buffer works ok (80 FPS). But in fullscreen mode, there is a fatal slow down of the application (1 FPS). If i disable the stencil buffer, window and fullscreen mode work with the same speed. The only difference between this two modes is, that the window mode runs in true color (32Bit/pixel) and the fullscreen mode runs with 16Bit/pixel. My graphiccard is a GeForce2. Has anyone an idea how i could solve this problem (without removing the stencil buffer Thx, Stone.

2

Have you tried using a 24bit vmode with 8bit stencil for fullscreen? Supposedly that should give you stencil buffer at no cost to performance (at least on TNT2s).

3

The stencil buffer is not accelerated in 16-bit colordepth on NVIDIA hardware. That’s why the application is running slow in 16-bit colordepth with a stencil buffer. You have to use 32-bit colordepth.

4

However did I hear that upcoming drivers will let this cease to be the case for GF2Mx’s & GF3’s?

5

Is there any way to use 16Bit color mode with a stencil buffer, or is a stencil buffer only in 32Bit color mode available on GeForce2 GTS ??
How could i see if the driver uses a software or hardware stencil buffer ?

6

There is absolutely no way to get a hardware stencil buffer in 16-bit color unless you have a GF3.

You don’t need new drivers to get 16-bit Z with 32-bit color with a GF2 MX. This has been supported since 6.xx drivers (if not longer).

  • Matt