3dfx Tools Advanced Features Help
Alpha Blending - This is used to enable dither subtraction on the destination color during alpha blending. When dither subtraction is enabled, the dither matrix used to convert 24-bit color to 16-bit color is subtracted from the destination color before applying the alpha-blending algorithm. Enabling dither subtraction is used to enhance image quality when performing alpha-blending. This is ignored when 32-bit color rendering is selected.
3D Filter Quality - The display image can be filtered by averaging pixel values. By using this overlay filter, the image quality for full-screen 3D applications can be improved. Selecting the High option will average more pixels than the Normal option, resulting in a smoother but blurrier image, while the Normal option averages fewer pixels for a sharper image. The High setting uses two adjacent horizontal pixels from a line and the two pixels on the line below (a 2x2 box filter) to create one output pixel. The Normal setting uses four adjacent samples on a line (a 4x1 linear filter) to create one output pixel.
Level of Detail Bias - This control changes the Level of Detail (LOD) bias used for MIP mapping. Moving the slider control will either add or subtract a bias from the LOD computed during MIP mapping, making textures appear either sharper or blurrier. Adding bias can result in improved visual detail, but may reduce performance accordingly. Also, excessive bias can result in texture aliasing.
Z-buffer Optimization - This entry enables an extension for optimizing the use of the Z-buffer. Selecting this option will allow for more effective use of the Z-buffer and may increase performance.
Glide Splash Screen - The 3dfx Glide logo screen appears when a program starts that uses the Glide API.
Legacy Compressed Textures - This enables an OpenGL extension for compressing legacy textures in FXT1 format. Selecting this option can provide more effective use of texture memory and may increase performance.
Alpha Blending - This is used to enable dither subtraction on the destination color during alpha blending. When dither subtraction is enabled, the dither matrix used to convert 24-bit color to 16-bit color is subtracted from the destination color before applying the alpha-blending algorithm. Enabling dither subtraction is used to enhance image quality when performing alpha-blending. This is ignored when 32-bit color rendering is selected.
3D Filter Quality - The display image can be filtered by averaging pixel values. By using this overlay filter, the image quality for full-screen 3D applications can be improved. Selecting the High option will average more pixels than the Normal option, resulting in a smoother but blurrier image, while the Normal option averages fewer pixels for a sharper image. The High setting uses two adjacent horizontal pixels from a line and the two pixels on the line below (a 2x2 box filter) to create one output pixel. The Normal setting uses four adjacent samples on a line (a 4x1 linear filter) to create one output pixel.
Level of Detail Bias - This control changes the Level of Detail (LOD) bias used for MIP mapping. Moving the slider control will either add or subtract a bias from the LOD computed during MIP mapping, making textures appear either sharper or blurrier. Adding bias can result in improved visual detail, but may reduce performance accordingly. Also, excessive bias can result in texture aliasing.
MIP Map Dithering - Enabling MIP map dithering will cause the hardware to blend between pairs of MIP map levels to produce a full continuum of texture levels. This can result in much smoother texturing. However, this can also decrease performance because dithered MIP Maps cannot be multi-textured.
Triple Buffering - Enabling Triple Buffering will allocate a third frame buffer. This frame buffer can increase performance by enabling the hardware to render at the same time that the 3D application performs other tasks. However, the additional frame buffer required for this uses up video memory that could otherwise be used for storing textures. Enabling Triple Buffering could hurt the performance of your 3D applications that use a lot of textures.
Maximum Buffered Frames - This allows you to limit the number of pending swap buffers to 0, 1, 2, or 3. A higher number of pending swap buffers can slow the system's response to input as all of the pending swap buffers are processed before the system proceeds to the next operation. Higher swaps leads to potentially higher frame rates, but at the same time increasing latency (waiting for the card to draw the frame).
Limit Texture Memory - This can be used to specify a limit of 2MB on the amount of texture memory reserved for the Texture Mapping Unit (TMU) in a Glide application. Some Glide applications, especially older Glide games, may require this 2MB limit.
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