Commodore 128D - Page 259

COLLISION
—Define handling for sprite collision interrupt
COLLISION type ^statement]
type.
statement
.Type of interrupt, as follows:
1 = Sprite-to-sprite collision
2 = Sprite-to-display data collision
3 = Light pen (40 column screen only)
.BASIC line number of a subroutine
When the specified situatioh occurs, BASIC will finish processing
the currently executing instruction and perform a GOSUB to the line
number given. When the subroutine terminates (it must end with a
RETURN), BASIC will resume processing where it left off. Interrupt
action continues until a COLLISION of the same type without a line
number is specified. More than one type of interrupt may be enabled
at the same time, but only one interrupt can be handled at a time
(i.e., there can be no recursion and no nesting of interrupts). The
cause of an interrupt may continue causing interrupts for some time
unless the situation is altered or the interrupt disabled.
When a sprite is completely off-screen and not visible, it cannot gen
erate an interrupt. To determine which sprites have collided since
the last check, use the BUMP function.
EXAMPLE:
COLLISION 1, 5000
COLLISION 1
COLLISION 2,1000
Detects a sprite-to-sprite collision
and program control sent to
subroutine at line 5000.
Stops interrupt action which was
initiated in above example.
Detects sprite-to-dal? collision and
program control directed to
subroutine in line 1000.
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BASIC 7.0 ENCYCLOPEDIA—Basic Commands and Statements