3dfx Gamma settings
Windows
3dfx cards are know for often having to tweak Gamma settings, especially on the early 3dfx cards. Newer cards default to a Gamma of 1.3 for games. You can adjust Gamma settings in the Windows drivers.
DOS
DOS you need to use environmental variables as shown below. The first three lines set the Gamma for red, green and blue. The fourth line sets the screen refresh in Hz. LCDs work best at 60 Hz but on CRT monitors 60 Hz was flickery and people often used 75 or 85 Hz. The final line enables V-sync (set to 1) or disables it (set to 0) to avoid tearing.
SET SST_RGAMMA=1.0
SET SST_GGAMMA=1.0
SET SST_BGAMMA=1.0
SET SST_SCREENREFRESH=60
SET FX_GLIDE_SWAPINTERVAL=1
glideenv.bat |
Note that some 3dfx game patches set Gamma to a specific setting and driver settings as well as environment variables will simply be ignored.
Tomb Raider with various Gamma settings
I used my AVerMedia Game Broadcaster capture card, which can capture directly through VGA, to capture the output of the game Tomb Raider displayed on a Diamond Monster 3D which is the 3dfx Voodoo. The gamme settings tested are:
I put all six videos into one project for easy comparison.
- 0.4
- 0.7
- 1.0
- 1.3
- 1.6
- 1.9
I put all six videos into one project for easy comparison.