2
And finally, the last effect (used as a Screen
Saver in the ZX-REVIEW 7-10 and ZX-FORUM
4):
140.
;--------------------------;
3; (c) Ivan Roshchin, 1997;
; EFFECT "PLASMA-3";
;--------------------------;
BUF EQU # 4000; address location
; Buffer length # 410
; Bytes (ml.bayt
, Address = 0!)
B_SCR EQU BUF + # 20; address of the first
; Updated row
; In buffer
B_UP EQU BUF; top line
B_DOWN EQU BUF + # 320; bottom line
SSAVER LD HL, (RND +1)
NEW_RND LD A, (HL)
INC HL
AND 7
CP 6
JR NC, NEW_RND
AND A
RLCA
RLCA
LD HL, TABL1
LD D, 0
LD E, A
ADD HL, DE
LD DE, BUF + # 400
LD BC, 4
LDIR
LD HL, TABL2
LD BC, 12
LDIR
; In H 'captures the high byte address
; Palette:
LD H, D
EXX
; Transfers the contents of the upper row
; Buffer area down and vice versa,
, Ie screen as it is closed vertically:
M2 LD HL, B_SCR
LD DE, B_DOWN
LD BC, 32
LDIR
LD HL, B_SCR + # 2E0
LD DE, B_UP
LD BC, 32
LDIR
; In the cycle of updating the attributes in the buffer:
LD IX, B_SCR
M1 LD A, (IX-32)
ADD A, (IX-1)
ADD A, (IX +1)
ADD A, (IX +32)
SRL A
SRL A
LD (IX), A
;-------------------------------------; On value bytes from the
buffer determine ; Its color and prints:
EXX
RRCA
RRCA
AND 15
LD L, A
LD A, (HL)
EXX
PUSH IX
POP HL
LD DE, # 5800-B_SCR
ADD HL, DE
EX AF, AF ';!
LD A, (IX-1)!
CP (IX);!
JR C, TO_SCR1;!
CP 16;!
JR C, TO_SCR1;!
DEC HL;!
LD A, (HL);!
INC HL;!
LD (HL), A;!
JR NO_CP;!
TO_SCR1 EX AF, AF ';!
LD (HL), A
;-------------------------------------
NO_CP INC IX
LD DE, 1 - # 5800 + B_SCR-B_DOWN
ADD HL, DE
LD A, H
OR L
JR NZ, M1
; Upgraded the entire buffer is now some
; Take on random bytes of buffer
; Values:
LD B, 5
L23 PUSH BC
CALL RND
POP BC
DJNZ L23
; On the keyboard is something clicked?
LD A, (23560)
AND A
JR Z, M2
RET
;=================================
; Procedure RND changes randomly
; It happened. selected number of
; Screen buffer (BUF.. BUF + # 400)
RND LD HL, 0
LD A, H
AND # 3F
LD H, A
LD D, (HL)
INC HL
LD E, (HL)
INC HL
LD A, (HL)
XOR D
XOR E
SUB 16
LD B, A
LD A, D
AND 3
LD D, A
LD E, B
LD (RND +1), HL
LD HL, BUF
ADD HL, DE
LD A, B
AND% 01111111
LD (HL), A
DEC HL
LD (HL), A
DEC HL
LD (HL), A
RET
; Palette:
TABL1 DB% 00001001
DB% 01001001
DB% 00011011
DB% 01011011
DB% 00001001
DB% 01001001
DB% 00101101
DB% 01101101
DB% 00010010
DB% 01010010
DB% 00011011
DB% 01011011
DB% 00010010
DB% 01010010
DB% 00110110
DB% 01110110
DB% 00100100
DB% 01100100
DB% 00101101
DB% 01101101
DB% 00100100
DB% 01100100
DB% 00110110
DB% 01110110
TABL2 DB% 00111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
DB% 01111111
2
Line marked with "!" Originally absent in this
program (such as it was used in the ZX-REVIEW 7-10), but
then they were added to
improve the appearance of the effect and
make smoother transitions
colors.
*
