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| Line of sight |
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Posted by: slenkar - 2012-02-15, 07:56 PM - Forum: How-To & Tutorials
- Replies (28)
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To see if 2 game characters can see each other you need 2 functions
distance:
Code: Function distance (x1 as Integer, y1 as Integer, x2 as Integer, y2 as Integer) as Integer
Dim x as Integer
x=ABS(x1-x2)
Dim y as Integer
y=ABS(y1-y2)
Return Sqr((x^2)+(y^2))
End Function
line:
Code: Function line(X1 as Integer,Y1 as Integer,X2 as Integer,Y2 as Integer) as Integer
'creates a line of individual co-ords from X1,Y1 to X2,Y2 at any angle
Dim dist as Integer
dist=distance(X1,Y1,X2,Y2)
dim bresiter as Integer
For bresiter=0 To dist
bresx(bresiter)=0
bresy(bresiter)=0
Next
Dim steep as Integer
if Abs(Y2-Y1) > Abs(X2-X1) then
steep=1
else
steep=0
end if
PRINT AT 1,0 ; PAPER 1 ; INK 0 ; "steep "+STR(steep)
If steep =1 Then
Dim Temp as Integer
Temp=X1
X1=Y1
Y1=Temp
Temp=X2
X2=Y2
Y2=Temp
End If
Dim DeltaX as Integer
DeltaX=Abs(X2-X1)
Dim DeltaY as Integer
DeltaY=Abs(Y2-Y1)
Dim IError as Integer
IError=0
Dim DeltaError as Integer
DeltaError=DeltaY
Dim x as Integer
x=X1 'Start at X1,Y1
Dim y as Integer
y=Y1
Dim XStep as Integer
Dim YStep as Integer
If X1<X2 Then
XStep=1
Else
XStep=-1
end if
If Y1<Y2 Then
YStep=1
Else
YStep=-1 'Direction
end if
Dim iter as Integer
iter=1
While x<>X2
x=x+XStep 'Move in X
IError=IError+DeltaError 'Add to counter
If (IError SHL 1)>DeltaX then 'Would it overflow?
y=y+YStep 'Move in Y
IError=IError-DeltaX 'Overflow/wrap the counter
End if
If steep then
bresx(iter)=y
bresy(iter)=x
Else
bresx(iter)=x
bresy(iter)=y
End If
iter=iter+1
If iter>dist then
'Print at 3,0;PAPER 1;INK 0;"bresenham over distance "+STR(dist)
Return dist
End If
Wend
Return dist
End Function
create 2 arrays to hold the x and y coordinates of the line
Code: Dim bresx(350) as Integer
Dim bresy(350) as Integer
The size of the arrays should be the distance of the longest line you intend to create
a line going across the screen of the speccy is about 322 in length
You have 2 characters on a playing field that has x and y coordinates
you call the line function:
one character is at 1,1
the other is at 100,95
Code: Dim dist as Integer
dist=line(1,1,100,95)
then finally you go through the co-ordinates on the line to check if anything is in the way, like walls or other characters
Code: Dim can_see:UByte
can_see=1
for x=0 to dist
if wall_in_way(bresx(x),bresy(x)) then
can_see=0
end if
next
if can_see =1 then
'yes they can see each other
end if
if can_see =0 then
'no they can not see each other
end if
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| 191 plots causes crash |
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Posted by: slenkar - 2012-02-14, 02:58 PM - Forum: Help & Support
- Replies (2)
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Code: Function distance (x1 as Integer, y1 as Integer, x2 as Integer, y2 as Integer) as Integer
Dim x as Integer
x=Abs(x1-x2)
Dim y as Integer
y=Abs(y1-y2)
Return x+y
End Function
Dim bresx(0 to 255) as Integer
Dim bresy(0 to 191) as Integer
Function line(X1 as Integer,Y1 as Integer,X2 as Integer,Y2 as Integer) as Integer
'Draws a line of individual pixels from X1,Y1 to X2,Y2 at any angle
Dim dist as Integer
dist=distance(X1,Y1,X2,Y2)
dim bresiter as Integer
For bresiter=0 To dist
bresx(bresiter)=0
bresy(bresiter)=0
Next
Dim steep as Integer
if Abs(Y2-Y1) > Abs(X2-X1) then
steep=1
else
steep=0
end if
PRINT AT 1,0 ; PAPER 1 ; INK 0 ; "steep "+STR(steep)
If steep =1 Then
Dim Temp as Integer
Temp=X1
X1=Y1
Y1=Temp
Temp=X2
X2=Y2
Y2=Temp
End If
Dim DeltaX as Integer
DeltaX=Abs(X2-X1)
Dim DeltaY as Integer
DeltaY=Abs(Y2-Y1)
Dim IError as Integer
IError=0
Dim DeltaError as Integer
DeltaError=DeltaY
Dim x as Integer
x=X1 'Start at X1,Y1
Dim y as Integer
y=Y1
Dim XStep as Integer
Dim YStep as Integer
If X1<X2 Then
XStep=1
Else
XStep=-1
end if
If Y1<Y2 Then
YStep=1
Else
YStep=-1 'Direction
end if
Dim iter as Integer
iter=1
While x<>X2
x=x+XStep 'Move in X
IError=IError+DeltaError 'Add to counter
If (IError SHL 1)>DeltaX then 'Would it overflow?
y=y+YStep 'Move in Y
IError=IError-DeltaX 'Overflow/wrap the counter
End if
If steep then
bresx(iter)=y
bresy(iter)=x
Else
bresx(iter)=x
bresy(iter)=y
End If
iter=iter+1
If iter>dist then
Print at 3,0;PAPER 1;INK 0;"bresenham over distance "+STR(dist)
Return dist
End If
Wend
Return dist
End Function
Dim dist as Integer
dist=line(1,1,100,95)-1
PRINT AT 0,0 ; PAPER 1 ; INK 0 ; "dist "+STR(dist)
for x=0 to dist
Plot bresx(x),bresy(x)
next
'PRINT AT 2,0 ; PAPER 1 ; INK 0 ; "bresx "+STR(bresx(108))
'PRINT AT 3,0 ; PAPER 1 ; INK 0 ; "bresx "+STR(bresx(57))
'PRINT AT 4,0 ; PAPER 1 ; INK 0 ; "bresx "+STR(bresx(18))
'PRINT AT 5,0 ; PAPER 1 ; INK 0 ; "bresy "+STR(bresy(108))
'PRINT AT 6,0 ; PAPER 1 ; INK 0 ; "bresy "+STR(bresy(59))
'PRINT AT 7,0 ; PAPER 1 ; INK 0 ; "bresy "+STR(bresy(1))
'main loop
100 LET j$ = INKEY$
GOTO 100
Im implementing a bresenham thingy for line of sight calculations,
whenever the length of the line exceeds 191 the screen gets corrupted,
191 just happens to be the height of the screen, but I dont see the relation.
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| type problem (*solved*) |
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Posted by: slenkar - 2012-02-14, 04:23 AM - Forum: Bug Reports
- Replies (10)
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Code: Function distance (x1 as Integer, y1 as Integer, x2 as Integer, y2 as Integer) as Integer
Dim x as Integer
x=Abs(x1-x2)
Dim y as Integer
y=Abs(y1-y2)
Return x+y
End Function
Dim bresx(0 to 300) as UByte
Dim bresy(0 to 300) as UByte
Function line(X1 as Integer,Y1 as Integer,X2 as Integer,Y2 as Integer) as Integer
'Draws a line of individual pixels from X1,Y1 to X2,Y2 at any angle
Dim dist as Integer
dist=distance(X1,Y1,X2,Y2)
dim bresiter as Integer
For bresiter=0 To dist
bresx(bresiter)=0
bresy(bresiter)=0
Next
Dim steep as Byte
steep=Abs(Y2-Y1) > Abs(X2-X1)
PRINT AT 1,1 ; PAPER 1 ; INK 0 ; "steep "+STR(steep)
If steep =1 Then
Dim Temp as Integer
steep=X1
X1=Y1
Y1=Temp
Temp=X2
X2=Y2
Y2=Temp
End If
Dim DeltaX as Integer
DeltaX=Abs(X2-X1)
Dim DeltaY as Integer
DeltaY=Abs(Y2-Y1)
Dim IError as Integer
IError=0
Dim DeltaError as Integer
DeltaError=DeltaY
Dim x as Integer
x=X1 'Start at X1,Y1
Dim y as Integer
y=Y1
Dim XStep as Integer
Dim YStep as Integer
If X1<X2 Then
XStep=1
Else
XStep=-1
end if
If Y1<Y2 Then
YStep=1
Else
YStep=-1 'Direction
end if
'If Steep Then Plot(Y,X) Else Plot(X,Y) 'Draw
Dim iter as Integer=1
While x<>X2
'Print x+" <x "+X2+"<x2"
'Print "xstep "+XStep
'x=truncate(x,1)
x=x+XStep 'Move in X
'Print x+" <x after adding xstep "+X2+"<x2"
IError=IError+DeltaError 'Add to counter
If (IError Shl 1)>DeltaX then 'Would it overflow?
y=y+YStep 'Move in Y
IError=IError-DeltaX 'Overflow/wrap the counter
End if
' x=truncate(x,1)
' y=truncate(y,1)
' Print x+" <x after truncating xstep "+X2+"<x2"
If steep then
bresx(iter)=y
' Print bresx[iter]+"<bresx iter>"+iter
bresy(iter)=x
' Print bresy[iter]+"<bresy iter>"+iter
Else
bresx(iter)=x
' Print bresx[iter]+"<bresx iter>"+iter
bresy(iter)=y
' Print bresy[iter]+"<bresy iter>"+iter
End If
iter=iter+1
If iter>dist then
Print "bresenham over distance "+dist
Return dist
End If
' If Steep Then Plot(Y,X) Else Plot(X,Y) 'Draw
Wend
Return dist
End Function
line(0,0,10,5)
for x=0 to 6
Plot bresx(x),bresy(x)
next
When I try to compile it says cant convert to string on line 16 but there are no strings being referred to on that line
EDIT- the problem was on line 107 so the compiler was confused
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| Astrology |
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Posted by: slenkar - 2012-02-01, 01:30 AM - Forum: Off-Topic
- Replies (3)
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hey, you can type in your birthday and get a description of your personality
LCD's birthday is on his website so I did his :
<!-- m --><a class="postlink" href="http://astro.cafeastrology.com/cgi-bin/astro/natal?member=&recalc=&name=LCD&sex=t&d1day=9&d1month=10&d1year=1971&d1hour=22&d1min=30&nohouses=true&citylist=Chorzow%2C+Poland&lang=en">http://astro.cafeastrology.com/cgi-bin/ ... nd&lang=en</a><!-- m -->
If LCD is reading this , does it match your personality?
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| Variables with random data in |
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Posted by: britlion - 2012-01-30, 12:39 AM - Forum: Bug Reports
- Replies (2)
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Not sure if it's a bug or design, but I seem to be finding random numbers in dimensioned arrays. I would have expected a DIM to set values to zero by default, I think?
Assuming that, and not looping through and setting them to zero is causing some very surprising values to pop up!
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| MegaLZ depacker |
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Posted by: britlion - 2012-01-29, 02:41 AM - Forum: How-To & Tutorials
- Replies (14)
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I was using MegaLZ, and I figured it worth listing how to make it a SUB.
Trivially easy, actually - it's provided as ASM source. There's a windows binary program to compress data. Just call this like a mem copy, with source (packed data) and destination (for unpacked data).
I've used it to pack down screen data, and just unpacked it to the screen - it's slow enough to be visible, so do it with attributes set to invisible, and the user won't notice.
Code: SUB megaLZDepack (source as uInteger, dest as uInteger)
ASM
LD E,(IX+6)
LD D,(IX+7)
;Z80 depacker for megalz V4 packed files (C) fyrex^mhm
; DESCRIPTION:
;
; Depacker is fully relocatable, not self-modifying,
;it's length is 110 bytes starting from DEC40.
;Register usage: AF,AF',BC,DE,HL. Must be CALL'ed, return is done by RET.
;Provide extra stack location for store 2 bytes (1 word). Depacker does not
;disable or enable interrupts, as well as could be interrupted at any time
;(no f*cking wicked stack usage :).
; USAGE:
;
; - put depacker anywhere you want,
; - put starting address of packed block in HL,
; - put location where you want data to be depacked in DE,
; (much like LDIR command, but without BC)
; - make CALL to depacker (DEC40).
; - enjoy! ;)
; PRECAUTIONS:
;
; Be very careful if packed and depacked blocks coincide somewhere in memory.
;Here are some advices:
;
; 1. put packed block to the highest addresses possible.
; Best if last byte of packed block has address #FFFF.
;
; 2. Leave some gap between ends of packed and depacked block.
; For example, last byte of depacked block at #FF00,
; last byte of packed block at #FFFF.
;
; 3. Place nonpackable data to the end of block.
;
; 4. Always check whether depacking occurs OK and neither corrupts depacked data
; nor hangs computer.
;
;DEC40
LD A,80h
EX AF,AF'
MS: LDI
M0: LD BC,2FFh
M1: EX AF,AF'
M1X: ADD A,A
JR NZ,M2
LD A,(HL)
INC HL
RLA
M2: RL C
JR NC,M1X
EX AF,AF'
DJNZ X2
LD A,2
SRA C
JR C,N1
INC A
INC C
JR Z,N2
LD BC,33Fh
JR M1
X2: DJNZ X3
SRL C
JR C,MS
INC B
JR M1
X6:
ADD A,C
N2:
LD BC,4FFh
JR M1
N1:
INC C
JR NZ,M4
EX AF,AF'
INC B
N5: RR C
JP C, END_DEC40
RL B
ADD A,A
JR NZ,N6
LD A,(HL)
INC HL
RLA
N6: JR NC,N5
EX AF,AF'
ADD A,B
LD B,6
JR M1
X3:
DJNZ X4
LD A,1
JR M3
X4: DJNZ X5
INC C
JR NZ,M4
LD BC,51Fh
JR M1
X5:
DJNZ X6
LD B,C
M4: LD C,(HL)
INC HL
M3: DEC B
PUSH HL
LD L,C
LD H,B
ADD HL,DE
LD C,A
LD B,0
LDIR
POP HL
JR M0
END_DEC40:
END ASM
END SUB
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| another forum area for other platforms than zx-spectrum |
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Posted by: nitrofurano - 2011-12-29, 12:01 AM - Forum: Wishlist
- Replies (41)
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Since Boriel told us that this zxbasic compiler is planned to be flexible enough to target other platforms than only zx-spectrum, maybe another are of this forum could be created, where we could discuss information and knowledge which could help on this, since i'm seeing that more people could be interested on helping
For example, i were about trying to create stuff for msx2+ (for example, using laced screen12 or screen7) using this zxbasic-compiler, but i'm concerned on how it could create incompatible binaries (like using rom calls or system variable accesses from zx-spectrum ), and targeting 'bloadable' binaries, or .rom files
(for example as well, would be interesting seeing stuff made for msxdev contest made with this Boriel's zxbasic-compiler)
I readed somewhere that Boriel mentioned other z80 machines as well, like Amstrad - btw, the idea is about this, having a kind of shared brainstorm here about all 8bit hardware manufactured (also like zx81, Mattel Aquarius, sharp mz700, nec pc6001, etc.), which components each one has and how are they used, how they deal with ansi-basic language, etc. - maybe we should start something on the wiki pages as well?
I think information like this, and accessible as well, can help a lot, not only the multiplatform cross-development target of this compiler, as can help as well retro developers and teams (like those wonderful Mojon Twins team) on developing on all these other hardware as well - this would be wonderful!
what do you all think about? and who can help, and on what?
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![[Image: QuestForWitchcraft.gif]](http://members.inode.at/838331/zx/QuestForWitchcraft.gif)
