Texture Filtering

When rendering textures, you often need filtering methods to determine the color of a fragment when it doesn’t align perfectly with a texel (texture pixel). Common filtering methods include:

1. Box (Nearest-Neighbor) Filtering

Description: Uses the nearest texel’s color for the fragment.
Effect: Fast but can look pixelated up close.
Info

Box filtering is computationally simple since it only considers the closest texel, but it can produce rough-looking textures.

2. Bilinear Filtering

Description: Uses the four closest texels and interpolates between them.
Effect: Creates smoother textures than box filtering.

Info

Bilinear filtering smooths out the texture but can still appear blurry when textures are scaled up.

3. Mipmapping

Description: Uses precomputed textures at multiple resolutions in a “pyramid” to render distant objects more smoothly.
Effect: Reduces aliasing and improves performance by selecting an appropriate texture level based on distance.

4. Trilinear Filtering

Description: An improvement on mipmapping that blends between levels to avoid visible transitions.
Effect: Smooths out transitions between mipmap levels, especially noticeable at mid-range distances.

You can think of mipmapping and trilinear filtering as...

choosing the “right size” texture for the job. Imagine switching to lower-resolution images the further away they are, which avoids unnecessary detail and reduces rendering workload.