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Graphics Programming
TVP4020
Programmers Reference Manual
126
3) Draw the primitives.
4) Send a PickResult command.
5) Poll the output FIFO waiting for the PickResult to have passed
through P
ERMEDIA
.
Block fills are ignored by the picking operation.
Extent Checking
In extent mode, active and/or passive fragments have their associated
XY coordinates compared to the MinRegion and MaxRegion registers
and if found to be outside the defined rectangular region, then the
appropriate register is updated with the new coordinate(s) to extend the
region. The Inside/Outside bit has no effect in this mode. Block fills are
included in the extent checking if the StatisticMode register is set to
include spans.
The MinRegion and MaxRegion registers are loaded to select the
maximum value (MinRegion) and minimum value (MaxRegion) for extent
checking. A coordinate is inside the region if:
X
min
≤
X
<
X
max
Y
min
≤
Y
<
Y
max
where X and Y are from the fragment and the min/max values are from
MinRegion and MaxRegion registers. This comparison is identical to the
one used in the scissor tests.
Once all the necessary primitives have been rendered the results can be
found using the MinHitRegion and MaxHitRegion commands, which
cause the contents of the MinRegion and MaxRegion registers
respectively to be written into the output FIFO (under control of the
FilterMode register).
5.15.3
Synchronization
The Sync command register provides a means of ensuring that P
ERMEDIA
has completed all outstanding actions such as localbuffer and
framebuffer accesses. Sync is filtered and written to the output FIFO in a
similar fashion to the other registers. The host can either poll for Syncs
by reading the output FIFO or await a Sync interrupt
If generation of an interrupt is required, then the most significant bit of
the Sync command register must be set,
and the filtering must be set-up
to at least allow the Sync to be written into the FIFO. If the FilterMode is
set-up so the Sync is not written to the FIFO, then Sync interrupts will
not be generated. The actual interrupt will not occur until the Sync data
or tag has passed through P
ERMEDIA
and is on the output of the FIFO.
Summary of Contents for TVP4020 PERMEDIA 2
Page 1: ...Texas Instruments TVP4020 PERMEDIA 2 Programmer s Reference Manual Issue 4 ...
Page 284: ...TVP4020 Programmers Reference Manual A Gouraud Shaded Triangle 275 ...
Page 292: ...TVP4020 Programmers Reference Manual Register Tables 283 ...
Page 314: ...TVP4020 Programmers Reference Manual Index 305 ...
Page 315: ...Index TVP4020 Programmers Reference Manual 306 Index ...
Page 323: ...Index TVP4020 Programmers Reference Manual 314 ...