I am attempting to set up SimulEyes VR 3D glasses with Descent 1 and 2 on an XP machine. These glasses are connected with a pass through adapter between the VGA port and the monitor. The software inserts a white line on the bottom scan line of the screen, a short line for the left eye, a long line for the right eye. The glasses read this line to alternate the LCD shutters for the left and right lenses. This creates the 3D effect.

This works quite well on a Win98 233MHz system I have. When I try to set it up on DOSBox the left and right images alternate too slowly creating a very noticeable flicker.

I had at first thought this was a limitation of the display, VR usually requires a high refresh rate of 70MHz, 80MHz or higher. I tried DOSBox with a CRT that supports these refresh rates with the same result.

When I run the games in the native XP command prompt, the VR display alternates at an adequate rate. There is of course no sound and the game play is too fast, but the display is capable of cycling fast enough to support the 3D effect.

How can I increase the refresh rate in DOSBox to eliminate this flicker?

I tried the same tests on 2 different machines, a Dell Precision M6400 notebook and a Dell Dimension B110 with the same results. I'll focus on the notebook for now since it is a higher end system.

My system information is as follows.

OS Name Microsoft Windows XP Professional Service Pack 3
System Manufacturer Dell Inc.
System Model Precision M6400
Processor x86 Family 6 Model 23 Stepping 10 GenuineIntel ~2660 Mhz
BIOS Version/Date Dell Inc. A03, 1/23/2009

Video adapter NVIDIA Quadro FX 2700M
Video RAM 512.00 MB (536,870,912 bytes)
Video Drivers nv4_disp.dll
Video Driver Version 6.14.11.7653

Audio IDT High Definition Audio CODEC
Audio Driver c:\windows\system32\drivers\sthda.sys (5.10.6124.0, 1.33 MB (1,392,819 bytes), 3/11/2009 7:49 PM)

Game versions are Descent v1.5, Descent 2 v1.2 (DOS)
Game resolutions 320x200 and 320x400 (tried them both)

DOSBox v0.73

The DOSBox config setting I use are the defaults set by Good Old Games:

[sdl]
fullscreen=true
fulldouble=false
fullresolution=original
windowresolution=original
output=surface
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper.txt
usescancodes=true

[dosbox]
language=
machine=vga
captures=capture
memsize=16 [render]
frameskip=0
aspect=false
scaler=normal2x

[cpu]
core=auto
cycles=auto
cycleup=500
cycledown=20

[mixer]
nosound=false
rate=22050
blocksize=2048
prebuffer=10

[sblaster]
sbtype=sb16
sbbase=220
irq=7
dma=1
hdma=5
mixer=true
oplmode=auto
oplrate=22050