Table of Contents Glide Programming Guide
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- 9Mipmap Blending
| grHints() informs Glide of special conditions regarding optimizations and operation. Each hintType controls a different optimization or mode of operation. Hints of a given type are ORed together into a hintMask. The default hintMask is 0x00.
The GR_HINT_ALLOW_MIPMAP_DITHER hint type controls whether or not GR_MIPMAP_NEAREST_DITHER mode can be used. If hintMask is zero, then GR_MIPMAP_NEAREST_DITHER mode cannot be enabled with grTexMipMapMode(). This is the default. To allow GR_MIPMAP_NEAREST_DITHER mode to be used, specify a non-zero hintMask with the hint, as shown below grHints( GR_HINT_ALLOW_MIPMAP_DITHER, 1 ); If you are considering using dithered mipmapping, measure performance with and without it. The trade-off is that there may be visible mipmap bands, which can be eliminated by using trilinear mipmapping. On multiple TMU boards this is a one-pass operation, otherwise it requires two passes. Alternatively, dithered mipmapping can be allowed but disabled for most polygons and enabled only for those polygons that require it. If there is no performance difference with and without dithered mipmapping, but the image quality did not improve with dithered mipmapping, don’t use it. As you enhance or extend your program, you run the risk of creating a situation in which performance loss due to dithered mipmapping could occur. It is best to selectively enable dithered mipmapping just for the polygons that require it. 9Mipmap BlendingTo reduce the effects of mipmap banding the hardware can perform a weighted blend between adjacent mipmap levels. This blend is a single pass operation on two TMU configurations and a two-pass operation on a single TMU configurations. Mipmap blending can be performed independently of the type of minification and magnification filtering being performed. Since mipmap blending is actually a form of texture combining, it is controlled by proper set up of the texture combine function. Download 6.22 Mb. Share with your friends:
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