Adding Information to hints.txt

Controlling Communications between STK and the Graphics Card

STK is shipped with the hints.txt file, which contains hints for the most common graphics cards. STK reads the file to optimally run STK for the graphics card in use.

To view the current settings in the Hints.txt file, access the OpenGL report. The hints file information is provided at the bottom of the Open GL report.

The Hints.txt file organizes information about graphics cards first by manufacturer, or vendor, and then by brand name, or renderer. Keyword phrases are used to set off important information. You can add, delete, or modify information in the hints.txt file. You can also add new graphics card information to the hints.txt file.

The hints.txt file can be located in one or more of the following folders, depending on user preference:

  1. <Config folder>\VO
  2. ProgramData\AGI\STK <version number>\STKData\VO
  3. <STK install folder>\STKData\VO

If hints.txt exists in more than one location, STK searches for the file in the order given above.

Adding New Graphics Card Information to the hints.txt File

To add information about a new graphics card to the hints.txt file:

  1. Open the hints.txt file in a standard text editor.
  2. Select Graphics Card Info from the Help menu. The OpenGL report is displayed.
  3. Scroll down to the Hints file information.
  4. Arrange the windows so that the Open GL report and the hints.txt file display side-by-side.
  5. Add the following keywords to the hints.txt file, using the information supplied in the report for the "<VendorName>" and "<Renderer>" keywords. Enclose these keywords in quotes.

    BeginVendor "<VendorName>"

                BeginRenderer "<Renderer>"

                      {ExtensionData1} <Value>

                      {ExtensionData2} <Value>

                EndRenderer

    EndVendor

{ExtensionData} are the commands that need to be included in the file in order to render the textures correctly. To finish adding information about a new graphics card to the hints.txt file, you'll need to call AGI's Support Engineers to determine the correct <value> for each {ExtensionData}. Once you've entered the correct values, save the file and restart STK.

Mipmapping and anisotropic filtering

By default, STK will use the best possible image filtering that your video card supports. This could be no mipmapping, basic mipmapping, or mipmapping with anisotropic filtering.

The STKData\VO\hints.txt file can effect the level of mipmapping.

The MIPMAP parameter can be set to true or false to enable or disable mipmapping. By default the MIPMAP value is set to true.

The other parameter is MAXUSEDANISOTROPY; this real value defines the maximum level of anistropy that STK will use. For example, a video card may support 1.0 to 16.0 levels of anistropy. The higher the number, the better the anisotropic filtering, where 1.0 means none, i.e., isotropic filtering. While a higher value improves visual quality, it also reduces frame rate however in cases with newer graphics cards this frame rate reduction should be negligible. If this parameter is not defined, STK defaults to using the highest value.

At the bottom of the graphics info report, you can see at what value MIPMAP and MAXUSEDANISOTROPY is set. There is also another value, MAXANISOTROPY, which is the maximum anisotropic value that the video card supports.