Table 7-4: CLXCON Bits
Bit
Number
Name
Function
15
ENSP7 Enable sprite 7 (OR with sprite
6)
14
ENSP5
Enable sprite 5 (OR with sprite 4)
13
ENSP3 Enable sprite 3 (OR with sprite
2)
12
ENSP1 Enable sprite 1 (OR with sprite
0)
11
ENBP6 Enable bit-plane 6 (match required for collision)
10
ENBP5 Enable bit-plane 5 (match required for collision)
9
ENBP4 Enable bit-plane 4 (match required for collision)
8
ENBP3
Enable bit-plane 3 (match required for collision)
7
ENBP2 Enable bit-plane 2 (match required for collision)
6
ENBPI
Enable bit-plane 1 (match required for collision)
5
MVBP6
Match value for bit-plane 6 collision
4
MVBP5
Match value for bit-plane 5 collision
3
MVBP4 Match value for bit-plane 4 collision
2
MVBP3 Match value for bit-plane 3 collision
1
MVBP2 Match value for bit-plane 2 collision
0
MVBP1 Match value for bit-plane 1 collision
Bits 15-12 let you specify
that
collisions with a sprite pair are
to
include the odd-
numbered sprite of a pair of sprites.
The
even-numbered sprites always are included
in
the
collision detection. Bits 11-6 let you specify whether to include
or
exclude specific
bit-planes from the collision detection. Bits 5-0 let you specify the polarity (true-false
condition) of bits
that
will cause a collision.
For
example, you may wish
to
register colli-
sions only when the object collides with "something green"
or
"something blue." This
feature, along with the collision enable bits, allows you
to
specify the exact bits, and
their polarity, for the collision
to
be registered.
NOTES
This
register is write-only. If all bit-planes are excluded (disabled), then a
bit-plane collision will
always
be
detected.
204 System Control Hardware
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