MB86293 Datasheet, PDF (83/285 Pages) Fujitsu Component Limited. – Grraphiics Conttrrollllerr Speciiffiicattiions

FUJITSU LIMITED
PRELIMINARY and CONFIDENTIAL
8.4.4 Filtering
CORAL supports two texture filtering modes: point filtering, and bi-linear filtering.
Point filtering
This mode uses the texture pixel specified by the (S, T) coordinates as they are for drawing. The
nearest pixel in the texture pattern is chosen according to the calculated (S, T) coordinates.
0.5 1.0 1.5 2.0
0.0
0.5
1.0
1.5
2.0
Bi-linear filtering
The four nearest pixels specified with (S, T) coordinate are blended according to the distance from
specified point and used in drawing.
0.5 1.0 1.5 2.0
0.0
C00
C10
0.5
1.0
1.5
2.0
C01
C11
8.4.5 Perspective correction
This function corrects the distortion of the 3D perspective in the texture mapping. For this correction, the
‘Q’ component of the texture coordinates (Q = 1/W) is set based on the W component of 3D coordinates of
the vertex.
When the texture coordinates are large values, the texture may not be drawn correctly when perspective
correction is performed. This phenomenon occurs due to the precision limitation of the arithmetical unit
for perspective correction. The coordinates for the texture that cannot be drawn normally vary with the
value of the Q component; as a guide, when this value, texture coordinates (S, T) is smaller than –2048 or
larger than 2048, normal drawing results are less likely to be obtained.
MB86293 CORAL_LQ
Graphics Controller
83
Specifications Rev. 1.1