TI99 Environment

CALL_COINC

Syntax

integer-variable = CALL_COINC(sprite1,sprite2,tolerance)

Description

The COINC function checks for collision (COINCidence) between sprite1 and sprite2. The parameter tolerance indicates the distance in pixels between the two sprites where they will report a collision. A collision occurs when the upper left-hand corner of both sprites is within the value specified by tolerance. Depending on the tolerance value, sprites may trigger a collision even if there is no apparent overlap.

Valid Function Values:
sprite1, sprite2 - an integer between 1 and maxsprites indicating the sprite number of the sprite being checked for collision.
tolerance = an integer indicating the distance in pixels between sprite1 and sprite2 that will report a collision.

Return values:
integer-variable: Returns 0 when there is no sprite collision or -1 when there is a collision between sprite1 and sprite2.

Example Code

`Call_Coinc function Test
repeat : tolerance$ = ti_input("Tolerance:") : tolerance = val(tolerance$) : until tolerance >= 0     
x1 = 180 : y1 = 96 : x2 = 100 : y2 = 96 
call_sprite(1,65,16,y1,x1,0,0) 
call_sprite(2,65,14,y2,x2,0,0)    
call_motion(1,0,-5) : call_motion(2,0,2)
do
	coinc = CALL_COINC(1,2,tolerance)
	if coinc = -1
		ti_printat(1,10,"COINC:"+str$(coinc))
		call_motion(1,0,0) : call_motion(2,0,0)
		call_clear()
		repeat
			tolerance$ = ti_input("Tolerance:")
			tolerance = val(tolerance$)
			until tolerance >= 0
		call_sprite(1,65,16,y1,x1,0,-5)
		call_sprite(2,65,14,y2,x2,0,2)
	endif
	ti_sync()
loop

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