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OpenGL/Glide Options
This section contains settings that you can use to
tweak display options for games/applications that use OpenGL &/or Glide for
rendering.
Screen
Capture Key. This setting can be used to bind a key for capturing
screenshots with the Voodoo 4/5 in OpenGL/Glide rendering modes. If you wish to
use this ensure that the key selected doesn't not interfere with the keyboard
controls used in the application/game in question. Screenshots will be saved
into the directory of the Application/Game being used.
3D Filter Quality.
Using this setting you can further improve image quality. The display image
can be filtered by averaging pixel values. Selecting High (uses 2 adjacent horizontal pixels from a line & the 2
pixels on the line below (a 2x2 box filter) to create 1 output pixel) will
result in more pixels being averaged, resulting in a sharper image. Selecting Normal
will average less pixels than High
(uses 4 adjacent samples on a line (a 4x1 linear filter) to create 1 output
pixel), resulting in a smoother, more blurred image. Selecting Automatic
will allow the program to use filtering as needed. I’d recommend setting this
to High.
Alpha Blending. This setting can be used to enable/disable
dither subtraction on the Destination colour during Alpha-Blending. When dither
subtraction is enabled, the dither matrix used to convert 24-bit
colour to 16-bit colour is subtracted from the destination colour before
applying the alpha-blending algorithm. Setting this to Automatic will allow the application in question to use dither
subtraction as necessary. Setting it to Sharper
will enable dither
subtraction, resulting in a sharper image. Setting it to Smoother will disable
dither subtraction, resulting in a smoother image. I’d recommend setting this
to Sharper.
NOTE – Setting 3D Filter Quality to High
& Alpha Blending to Sharper will enable the use of a
special post
filter (This article is for the Voodoo 5 although the Voodoo 3 uses the same
process) which results in effectively 22-bit colour. This will provide optimal
image quality with the Voodoo 3.
Glide Splash Screen. Set
this to Disable to disable the
3dfx logo appearing when you load a game that uses Glide. Set it to Enable to display the logo, which serves no real purpose. Leave it
set to Disable.
Depth Precision (16 Bit). This setting is used to select the precision used
for depth calculations in 16-bit colour modes. This can improve performance,
particularly at higher resolutions. A side effect of the imprecision with
selecting Fast, or Faster is that you may see visual errors in
games. Selecting Disable will yield best image quality. I’d recommend
setting this to Fast.
Depending on the game I’d recommend selecting Fast,
although you may want to use Disable should you notice a big decrease in
image quality. Remember this setting only takes effect when running an
OpenGL/Glide games.
Hidden
Surface Removal.
This setting isn’t available unless you have installed the x3dfx beta drivers
for Windows 9x/Me/2000. Hidden Surface Removal support is currently limited in
both implementation & games supported. As such I won’t cover it in this
guide, please check our Hidden
Surface Removal – How to, Fixes & Benchmarks article for
more information on how to use this feature.
Level of Detail Bias.
Using this
setting you can make textures appear sharper or blurrier. This is quite useful
& can enhance texture quality greatly. The performance hit when using this
is negligible also. Valid ranges for this are –2 to 2.
Don’t set it higher than 0 though as image quality will be worse
(blurred) & there is no useful performance gain.
Here’s what the LOD bias does. LOD
bias modifies the calculation of texture level of detail parameter LOD. Often a
texture is oversampled or filtered such that the texture is band limited at
lower frequencies in one or more dimensions. The result is that texture-mapped
primitives appear excessively blurry. LOD bias provides biases in the LOD
calculation to compensate for under or over sampled texture images. Mipmapped
textures can be made to appear sharper or blurrier by supplying a negative or
positive bias respectively. I’d recommend setting this to 0 – 0.50
for optimal texture quality, with minimal artifacts.
Limit Texture Memory. This setting is included for compatibility purposes only.
Should you have an old game (Red Baron I believe in one such game) which refuses
to work with your Voodoo 3 try setting this to Limit Texture Memory to 2MB,
at all other set this to Software Controlled. Setting this to Software
Controlled will provide optimal performance with all other
applications/games.
Maximum Buffered Frames.
This setting allows you to limit the amount of pending swap buffers. Setting
this too High can hinder your system's response to input (Game
Controller’s or other devices) as all of the pending swap buffers are
processed before the system proceeds to the next operation. However a Higher
amount of swap buffers can also lead to higher frame rates, but at the
same time increasing latency (waiting for the card to draw the frame). I’d
recommend leaving this set to 1 or 2
personally.
MIP Map Dithering.
Using this setting you can enable smooth
transitions between textures (more specifically, between mip-map levels). This
will result in improved image quality, although potentially reduce performance
as dithered mip-maps can’t be multi-textured.
I’d recommend setting this to Enable unless you really need to increase
performance, in which case set it to Disable.
Triple
Buffering. Triple
buffering allocates a 3rd frame buffer. This frame buffer can improve
performance by allowing the hardware to render at the same time that the 3D
application performs other tasks. Set
this to Enable for improved
performance. With some games however, such as Quake 3, you should Disable this.
This is because triple buffering requires extra video memory, so for games that
have a large amount of textures you may improve performance by setting it to Disable
instead. For games that don’t use too much texture memory enable this
for a performance boost.
Vertical Sync.
Using this setting you may disable vsync in all OpenGL/Glide games, or
in-game settings to determine whether vsync is enabled/disabled.
Vsync effectively limits the frame rate to your current refresh rate at a given
resolution.
Performance can improve with vsync disabled
(Frames are rendered as fast as they can be regardless of refresh rate),
although you can experience image tearing &/or controller lag as a result.
With vsync enabled you won’t experience either image tearing nor
controller lag, although frame rate will be limited to your refresh rate. As
such I’d recommend enabling vsync for best image quality & disabling
it when you intend to benchmark system/game performance.
I’d recommend selecting Software
Controlled & choosing your vsync preference according to game (e.g. In
Quake 3 you can disable vsync via the config file). Select Disable
if you wish to disable vsync for all OpenGL/Glide games, this is useful
if you own games which do not have any setting to disable it in-game.
Select Enable if you wish to enable
vsync for all OpenGL/Glide games, again, this is useful if you own games which
do not have any setting to enable it in-game.
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