Deleted
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Posts: 0
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Post by Deleted on Jul 20, 2015 9:31:40 GMT -5
I've always ran into this problem with collision maps and BEX. The logic seems correct but I always get sketchy results at the boundaries. In this case my collision map is 32x32 big. Each block, sprite or empty space is 2x2 tiles each.
Right now I don't care that the character moves half-way into the bricks. My main concern is that the collision map fails usually at the borders. The "Bam!" text is close to the borders and you can move there is see the bad behavior.
Any idea what's going on?
dim colmap(32,32) as integer
const #false = 0
const #true = 1
const #farwest = 128
const #farnorth = 128
const #farsouth = 336
const #fareast = 432
pallettes palExport0,0,0,16
loadtiles smiley_tiles,4,256
loadtiles brick_tiles,4,260
smiley_id=addsprite(2,2)
propsprite smiley_id,256,0
brick_id=addsprite(2,2)
propsprite brick_id,260,0
print "Bam!"
palExport0:
DATAINT $0000,$0EEE,$0A88,$0000,$002E,$02AE,$00EE,$04E0 ' Palette:
DATAINT $0E82,$0E06,$024A,$0EAE,$0EE6,$0082,$0E22,$0E0E
init:
camera_x = 280
camera_y = 234
for i=0 to 32
drawbrick rnd(32), rnd(32)
next
goto main
main:
read_joystick
counter = counter%256 + 1
on vblank gosub drawscreen:
enable interrupt vblank
locate 1,1
sleep 1
print smiley_x, smiley_y
goto main
drawscreen:
lastx = camera_x : lasty = camera_y
if up_pressed > 0 then camera_y = (camera_y - 1)%512
if down_pressed > 0 then camera_y = (camera_y + 1)%512
if left_pressed > 0 then camera_x = (camera_x - 1)%512
if right_pressed > 0 then camera_x = (camera_x + 1)%512
if colmap(((camera_x/16)+10)%32,((camera_y/16)+7))%32 = 1 then camera_x = lastx : camera_y = lasty
SCROLL2 LEFT, camera_x
SCROLL2 UP, camera_y
movesprite smiley_id,280,232
return
DECLARE SUB drawbrick(tilex as integer, tiley as integer)
colmap(tilex, tiley) = 1
DRAWTILESINC 260, (tilex*2), (tiley*2), 2, 2
END SUB
DECLARE SUB read_joystick()
joystick_state=JOYPAD()
IF joystick_state.0 THEN up_pressed = up_pressed + 1 ELSE up_pressed = #false
IF joystick_state.1 THEN down_pressed = down_pressed + 1 ELSE down_pressed = #false
IF joystick_state.2 THEN left_pressed = left_pressed + 1 ELSE left_pressed = #false
IF joystick_state.3 THEN right_pressed = right_pressed + 1 ELSE right_pressed = #false
IF joystick_state.4 THEN b_pressed = b_pressed + 1 ELSE b_pressed = #false
IF joystick_state.5 THEN c_pressed = c_pressed + 1 ELSE c_pressed = #false
IF joystick_state.6 THEN a_pressed = a_pressed + 1 ELSE a_pressed = #false
IF joystick_state.7 THEN start_pressed = start_pressed + 1 ELSE start_pressed = #false
END SUB
smiley_tiles:
DATALONG $777777BB ' Tile #0
DATALONG $777777BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $7777BBBB
DATALONG $7777BBBB
DATALONG $777777BB ' Tile #1
DATALONG $777777BB
DATALONG $7777BBBB
DATALONG $7777BBBB
DATALONG $77BBBB77
DATALONG $77BBBB77
DATALONG $77777777
DATALONG $77777777
DATALONG $BB777777 ' Tile #2
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB77BB77
DATALONG $BB77BB77
DATALONG $BBBB7777
DATALONG $BBBB7777
DATALONG $BB777777 ' Tile #3
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB777777
DATALONG $77BB7777
DATALONG $77BB7777
DATALONG $77BBBB77
DATALONG $77BBBB77
brick_tiles:
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 20, 2015 10:50:23 GMT -5
Change .. if colmap(((camera_x/16)+10)%32,((camera_y/16)+7))%32 = 1 then.. into .. x = ((camera_x/16)+10)%32
y = ((camera_y/16)+ 7)%32
if colmap(x,y) thenBut since there are many things you can / should improve, here's a demo with the same "stick-on-wall" collision behavior. dim map(31,31) as integer
disable screen
loadtiles tiles,4,1
s = addsprite(1,1)
propsprite s,7,0
movesprite s,284,236
for i=0 to 127
x = rnd(32)
y = rnd(32)
map(x,y) = 1
drawtiles block,1,x<<1,y<<1,2,2
next
enable screen
on vblank gosub main
enable interrupt vblank
end
main:
j = joypad()
lx = cx
ly = cy
cx = cx+j.3-j.2 AND 511
cy = cy+j.1-j.0 AND 511
x = cx>>4
y = cy>>4
if map(x,y) then
cx = lx
cy = ly
endif
scroll2 right,672-cx
scroll2 up,cy-112
return
block:
data 0,1
data 2,3
tiles:
datalong $11111111
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $11111111
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $11111111
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $11111111
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 20, 2015 11:25:07 GMT -5
Thanks for the response, man!
The code still breaks when I try to check for collisions in a 2x2 tile area (size of the player sprite)
Both your modification of my code and your provided example work great for a single point. Still seems like the collision map gets corrupted when I try expanding that to a 16x16 pixel area. I'm not sure what's going on still. Ack.
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Deleted
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Posts: 0
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Post by Deleted on Jul 20, 2015 11:55:02 GMT -5
The code still breaks when I try to check for collisions in a 2x2 tile area. Works just fine for me .. dim map(31,31) as integer
disable screen
loadtiles tiles,4,1
s = addsprite(2,2)
propsprite s,1,0
movesprite s,280,232
for i=0 to 127
x = rnd(32)
y = rnd(32)
map(x,y) = 1
drawtiles block,1,x<<1,y<<1,2,2
next
cx = 48
enable screen
on vblank gosub main
enable interrupt vblank
end
main:
j = joypad()
lx = cx
ly = cy
cx = cx+j.3-j.2 AND 511
cy = cy+j.1-j.0 AND 511
x1 = cx>>4
x2 = cx+15>>4 AND 31
y1 = cy>>4
y2 = cy+15>>4 AND 31
c1 = map(x1,y1) ' Using READINT instead would be faster
c2 = map(x2,y1) '
c3 = map(x1,y2) '
c4 = map(x2,y2) '
if c1 OR c2 OR c3 OR c4 then
cx = lx
cy = ly
endif
scroll2 right,664-cx
scroll2 up,cy-104
return
block:
data 0,2
data 1,3
tiles:
datalong $11111111
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $10000000
datalong $11111111
datalong $11111111
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $00000001
datalong $11111111
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 20, 2015 12:12:06 GMT -5
I appreciate you're working through this with me. I think I identified the code you changed to get correct results with the collision map but I'm getting different results when I apply it to my own code. I also noticed we sometimes use modulus differently and my way is probably wrong. Although I see you use rnd(32) when you use modulus it's 31 (or 511). am I throwing off the calculations by doing that?
This is my current code that doesn't work:
dim colmap(32,32) as integer
const #false = 0
const #true = 1
const #farwest = 128
const #farnorth = 128
const #farsouth = 336
const #fareast = 432
pallettes palExport0,0,0,16
loadtiles smiley_tiles,4,256
loadtiles brick_tiles,4,260
smiley_id=addsprite(2,2)
propsprite smiley_id,256,0
brick_id=addsprite(2,2)
propsprite brick_id,260,0
print "Bam!"
palExport0:
DATAINT $0000,$0EEE,$0A88,$0000,$002E,$02AE,$00EE,$04E0 ' Palette:
DATAINT $0E82,$0E06,$024A,$0EAE,$0EE6,$0082,$0E22,$0E0E
init:
camera_x = 280
camera_y = 234
for i=0 to 32
drawbrick rnd(32), rnd(32)
next
goto main
main:
read_joystick
counter = counter%256 + 1
on vblank gosub drawscreen:
enable interrupt vblank
locate 1,1
sleep 1
print smiley_x, smiley_y
goto main
drawscreen:
lastx = camera_x : lasty = camera_y
if up_pressed > 0 then camera_y = (camera_y - 1)%512
if down_pressed > 0 then camera_y = (camera_y + 1)%512
if left_pressed > 0 then camera_x = (camera_x - 1)%512
if right_pressed > 0 then camera_x = (camera_x + 1)%512
x1 = camera_x>>4
x2 = camera_x-1>>4+1 AND 31
y1 = camera_y>>4
y2 = camera_y-1>>4+1 AND 31
c1 = colmap(x1,y1) ' Using READINT instead would be faster
c2 = colmap(x2,y1) '
c3 = colmap(x1,y2) '
c4 = colmap(x2,y2) '
if c1 OR c2 OR c3 OR c4 then camera_x = lastx : camera_y = lasty
SCROLL2 LEFT, camera_x
SCROLL2 UP, camera_y
movesprite smiley_id,280,232
return
DECLARE SUB drawbrick(tilex as integer, tiley as integer)
colmap(tilex, tiley) = 1
DRAWTILESINC 260, (tilex*2), (tiley*2), 2, 2
END SUB
DECLARE SUB read_joystick()
joystick_state=JOYPAD()
IF joystick_state.0 THEN up_pressed = up_pressed + 1 ELSE up_pressed = #false
IF joystick_state.1 THEN down_pressed = down_pressed + 1 ELSE down_pressed = #false
IF joystick_state.2 THEN left_pressed = left_pressed + 1 ELSE left_pressed = #false
IF joystick_state.3 THEN right_pressed = right_pressed + 1 ELSE right_pressed = #false
IF joystick_state.4 THEN b_pressed = b_pressed + 1 ELSE b_pressed = #false
IF joystick_state.5 THEN c_pressed = c_pressed + 1 ELSE c_pressed = #false
IF joystick_state.6 THEN a_pressed = a_pressed + 1 ELSE a_pressed = #false
IF joystick_state.7 THEN start_pressed = start_pressed + 1 ELSE start_pressed = #false
END SUB
smiley_tiles:
DATALONG $777777BB ' Tile #0
DATALONG $777777BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $77BB77BB
DATALONG $7777BBBB
DATALONG $7777BBBB
DATALONG $777777BB ' Tile #1
DATALONG $777777BB
DATALONG $7777BBBB
DATALONG $7777BBBB
DATALONG $77BBBB77
DATALONG $77BBBB77
DATALONG $77777777
DATALONG $77777777
DATALONG $BB777777 ' Tile #2
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB77BB77
DATALONG $BB77BB77
DATALONG $BBBB7777
DATALONG $BBBB7777
DATALONG $BB777777 ' Tile #3
DATALONG $BB777777
DATALONG $BB777777
DATALONG $BB777777
DATALONG $77BB7777
DATALONG $77BB7777
DATALONG $77BBBB77
DATALONG $77BBBB77
brick_tiles:
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
DATALONG $11001111 ' Tile #0
DATALONG $10220111
DATALONG $10320111
DATALONG $11001111
DATALONG $11111011
DATALONG $11110201
DATALONG $11111011
DATALONG $11111111
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 20, 2015 12:24:02 GMT -5
Hmmn. well, if my use of this code seems correct to you then there must be a different problem. I'll keep looking. Thank you! UPDATE: My hunch is that I have different offsets for the sprite position in the world map.
x1 = camera_x>>4
x2 = camera_x-1>>4+1 AND 31
y1 = camera_y>>4
y2 = camera_y-1>>4+1 AND 31
c1 = colmap(x1,y1) ' Using READINT instead would be faster
c2 = colmap(x2,y1) '
c3 = colmap(x1,y2) '
c4 = colmap(x2,y2) '
if c1 OR c2 OR c3 OR c4 then camera_x = lastx : camera_y = lasty
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Deleted
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Posts: 0
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Post by Deleted on Jul 20, 2015 14:25:17 GMT -5
Sorry to post again. Just want to thank titan. I took the hint that my code was a jumbled mess and am working towards using your style. I think your last example is the answer to this topic.
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Deleted
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Post by Deleted on Jul 22, 2015 5:59:26 GMT -5
I also noticed we sometimes use modulus differently and my way is probably wrong. There's nothing wrong with using modulus per-se .. it's just ( around ) 35 times slower than using AND. Of course you can only use AND as a modulo substitute when the modulus is a power-of-two, but that's yet another reason to keep things power-of-two. So, even though the following two lines give you the exact same result, one is fast while the other is ( very ) slow. x = i % 32
x = i AND 31 |
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