JPG and point() command issues - GameCreators Forum

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Ooska

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Joined: 29th Aug 2004

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Posted: 15th Aug 2006 00:24 Edited at: 15th Aug 2006 00:25

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Alright so I made a simple side-scroller type game with color coded collision. Using the point command. If the little guy hits black, gravity is 0, otherwise hes falling. So the collision detection has been working well untill I decided to use a picture I took with my camera and put ladders and walls everywhere so that it looks like your interacting with the picture. And for some reason detection is not working with JPGs... I took a closer look at my picture after I saved it and the true black (0,0,0) I painted over the picture with, was (0,1,0) and other variants. How can I stop this from happening?

I am using Paint to modify the picture.

Oh and heres my code

sync on
sync rate 100
load image "map2.jpg",1
paste image 1,0,0
load image "man.bmp",2
load image "grave.bmp",3
load image "portal1.bmp",4
load image "boost.bmp",5
load sound "beam.wav",1
load sound "tt.wav",3
load sound "explosion[1].wav",2
load image "explosion.bmp",6
hide mouse

do
if clicked=1 then goto skipp
xx=mousex()
yy=mousey()
skipp:
yyy=mousey()
xxx=mousex()
sprite 10,xx,yy,4
sprite 11,xxx,yyy,4
if clicked=1 and mouseclick() then remembery1=yyy : rememberx1=xxx : goto game1:
if mouseclick() then rememberx=xx : remembery=yy : clicked=1 : wait 500
sync
loop

game1:

do
sprite 10,rememberx,remembery,4
sprite 11,rememberx1,remembery1,4

if inkey$()="w" then goto cheat

sprite 1,x,y,2
if falltime>30 and  point(x+15,y+20)=rgb(0,0,0) then paste image 3,x,y  : sprite 1,x,y-20,6 : play sound 2 : wait 500 : x=0 : y=0 : falltime=0
gravity=4

`floor
if point(x+15,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3 else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x-1,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x+7,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1

`walls
if point(x-1,y-1)=rgb(0,0,0) then leftspeed=0
if point(x+15,y-1)=rgb(0,0,0) then rightspeed=0
if point(x-1,y+10)=rgb(0,0,0) then leftspeed=0
if point(x+15,y+10)=rgb(0,0,0) then rightspeed=0

`ladders
if point(x+9,y+11)=rgb(255,0,0) then ladder=1 else ladder = 0
if ladder=1 then gravity=0

if rightkey() then inc x,rightspeed
if leftkey() then dec x,leftspeed
if spacekey() and gravity =0 then goto jump
if upkey() and ladder=1 then dec y,3
if downkey() and ladder=1 then inc y,3

if gravity=4 then inc falltime else falltime=0

if sprite hit(1,10) then x=rememberx1 : y=remembery1 : play sound 1

inc y,gravity
sync
loop

jump:
g=5
fx=x
fy=y
do
dec y,g
dec g,1
if y=fy or point(x+10,y+20)=rgb(0,0,0) then goto game1
if point(x-1,y+20)=rgb(0,0,0) then ll=0 else rr=3
if point(x+15,y+10)=rgb(0,0,0) then rr=0 else ll=3
if rightkey() then inc x,rr
if leftkey() then dec x,ll
play sound 3

sprite 1,x,y,5
sync
loop

cheat:
do
if inkey$()="w" then dec y,3 else goto game1

sprite 1,x,y,5
if rightkey() then inc x,4
if leftkey() then dec x,4
sync
loop

+ Code Snippet

sync on
sync rate 100
load image "map2.jpg",1
paste image 1,0,0
load image "man.bmp",2
load image "grave.bmp",3
load image "portal1.bmp",4
load image "boost.bmp",5
load sound "beam.wav",1
load sound "tt.wav",3
load sound "explosion[1].wav",2
load image "explosion.bmp",6
hide mouse



do
if clicked=1 then goto skipp
xx=mousex()
yy=mousey()
skipp:
yyy=mousey()
xxx=mousex()
sprite 10,xx,yy,4
sprite 11,xxx,yyy,4
if clicked=1 and mouseclick() then remembery1=yyy : rememberx1=xxx : goto game1:
if mouseclick() then rememberx=xx : remembery=yy : clicked=1 : wait 500
sync
loop


game1:

do
sprite 10,rememberx,remembery,4
sprite 11,rememberx1,remembery1,4

if inkey$()="w" then goto cheat

sprite 1,x,y,2
if falltime>30 and  point(x+15,y+20)=rgb(0,0,0) then paste image 3,x,y  : sprite 1,x,y-20,6 : play sound 2 : wait 500 : x=0 : y=0 : falltime=0
gravity=4

`floor
if point(x+15,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3 else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x-1,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x+7,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1

`walls
if point(x-1,y-1)=rgb(0,0,0) then leftspeed=0
if point(x+15,y-1)=rgb(0,0,0) then rightspeed=0
if point(x-1,y+10)=rgb(0,0,0) then leftspeed=0
if point(x+15,y+10)=rgb(0,0,0) then rightspeed=0

`ladders
if point(x+9,y+11)=rgb(255,0,0) then ladder=1 else ladder = 0
if ladder=1 then gravity=0

if rightkey() then inc x,rightspeed
if leftkey() then dec x,leftspeed
if spacekey() and gravity =0 then goto jump
if upkey() and ladder=1 then dec y,3
if downkey() and ladder=1 then inc y,3

if gravity=4 then inc falltime else falltime=0

if sprite hit(1,10) then x=rememberx1 : y=remembery1 : play sound 1



inc y,gravity
sync
loop





jump:
g=5
fx=x
fy=y
do
dec y,g
dec g,1
if y=fy or point(x+10,y+20)=rgb(0,0,0) then goto game1
if point(x-1,y+20)=rgb(0,0,0) then ll=0 else rr=3
if point(x+15,y+10)=rgb(0,0,0) then rr=0 else ll=3
if rightkey() then inc x,rr
if leftkey() then dec x,ll
play sound 3

sprite 1,x,y,5
sync
loop



cheat:
do
if inkey$()="w" then dec y,3 else goto game1

sprite 1,x,y,5
if rightkey() then inc x,4
if leftkey() then dec x,4
sync
loop

Read Ender's Game. And all its sequels.

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Trowbee

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Joined: 12th Apr 2003

Location: United Kingdom

Posted: 15th Aug 2006 01:59

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JPG lose quality, by merging pixel colour with others surrounding it.
Unfortunately, if you want per-pixel collision, don't use JPG.
Use PNG, as its lossless, but also compressed so you don't get the nasty file sizes.

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Sixty Squares

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Joined: 7th Jun 2006

Location: Somewhere in the world

Posted: 15th Aug 2006 02:04 Edited at: 15th Aug 2006 02:06

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Well, you could 1, paint over all of the black with a true black color. Or, you couls make it so that you are on the ground even when the black is not exactly black, but a small variation of black. Maybe if Point(x,y)<rgb(50,50,50) or something like that. I'm not sure how that RGB stuff works.

So, this:

+ Code Snippet

`floor
if point(x+15,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3 else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x-1,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x+7,y+20)=rgb(0,0,0) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1

`walls
if point(x-1,y-1)=rgb(0,0,0) then leftspeed=0
if point(x+15,y-1)=rgb(0,0,0) then rightspeed=0
if point(x-1,y+10)=rgb(0,0,0) then leftspeed=0
if point(x+15,y+10)=rgb(0,0,0) then rightspeed=0

becomes this:

+ Code Snippet

`floor
if point(x+15,y+20)<rgb(50,50,50) then gravity=0 : rightspeed=3 : leftspeed=3 else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x-1,y+20)<rgb(50,50,50) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1
if point(x+7,y+20)<rgb(50,50,50) then gravity=0 : rightspeed=3 : leftspeed=3  else gravity = 4 : rightspeed=1 : leftspeed=1

`walls
if point(x-1,y-1)<rgb(50,50,50) then leftspeed=0
if point(x+15,y-1)<rgb(50,50,50) then rightspeed=0
if point(x-1,y+10)<rgb(50,50,50) then leftspeed=0
if point(x+15,y+10)<rgb(50,50,50) then rightspeed=0

This is a guess, so if it doesn't work change it right back

Use the Search/Replace feature for this it helps a TON. Select a certain amount of text or it will do the entire program. It's located in the EDIT tab.

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Ooska

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Joined: 29th Aug 2004

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Posted: 15th Aug 2006 02:28

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OK, thank you. I will try that idea. How can I change my JPG images into PNG?

Read Ender's Game. And all its sequels.

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Trowbee

22

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Joined: 12th Apr 2003

Location: United Kingdom

Posted: 15th Aug 2006 03:04 Edited at: 15th Aug 2006 03:57

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if Point(x,y)<rgb(50,50,50) wouldn't work unfortunatly.
The rgb command performs a calculation on the red, green and blue values;
(red*[255x255]) + (blue*255) + (green)
So, rgb(50,50,50) yields an internal result of 3,264,050
Thats a lot of colour that could be mistaken as a side effect

.
Pretty much anything without a high red value in would be mistaken for being black:
bright blue = rgb(0,0,255) = 255
bright green = rgb(0,255,0) = 65,025
And so on.

Something along the lines of:

+ Code Snippet

function check_pixel(x, y)
   col=point(x,y)
   output=0
   if rgbr(col)<50 AND rgbg(col)<50 AND rgbb(col)<50
      output=1
   endif
endfunction output

should work as you want, although point is pretty slow, so be warned.
Returned values are 1, if the pixel is below 50, otherwise 0

Additionally, you can just use paint to convert to PNG. However, now that you saved as jpg, the pixels that have been lost are now lost, so you'd have to retake the photo in high quality or a different format.

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Ooska

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Joined: 29th Aug 2004

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Posted: 16th Aug 2006 06:12

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OK, yeah, I converted the image to a PNG, and everything is working. Thanks.

Read Ender's Game. And all its sequels.

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DarkBASIC Discussion / JPG and point() command issues