Drawn images using ImageBuffer do not show

Blitz3D Forums/Blitz3D Beginners Area/Drawn images using ImageBuffer do not show

maneesh

(Posted 2005) [#1]

Hello

I am writing a program that Draws and Image in an Imagebuffer (using createImage and Plot) and then Tiles the image across the screen. However, the Tile does not work until after I have run the program, clicked another window, and clicked back on to the program. This seems to be an event error, but I don't know how to correct it.

Following is the code.

;INITIALIZATION

;Set up the graphics
Graphics 800,600,0,2

;Seed the Random Generator
SeedRnd MilliSecs()

;CONSTANTS
;The length of each block
Const LENGTH = 100

;The height of each block
Const HEIGHT = 100

;The amount of dots in each block
Const DOTS = 100
;END CONSTANTS

;IMAGES
;Create the dotfield image
dotfieldimage = CreateImage(LENGTH,HEIGHT)
;END IMAGES

;For each dot, draw a random dot at a random location
For loop = 0 To DOTS ;For every star
;draw only on created image
SetBuffer ImageBuffer(dotfieldimage)

;Plot the dot
Plot Rnd(LENGTH), Rnd(HEIGHT)

Next

;Set buffer back to normal
SetBuffer FrontBuffer()
;END INITIALIZATION

;MAIN LOOP

;Tile the image until the user quits (presses ESC)
While Not KeyDown(1)
TileImage dotfieldimage
Wend

;END MAIN LOOP

Thank you

-Maneesh

Conan

(Posted 2005) [#2]

must be an error in your computer, works fine for me

maneesh

(Posted 2005) [#3]

The error is more obvious (happens 100% of the time) if you change the Graphics code to

Graphics 800,600

So the code becomes:

;INITIALIZATION

;Set up the graphics
Graphics 800,600

;Seed the Random Generator
SeedRnd MilliSecs()

;CONSTANTS
;The length of each block
Const LENGTH = 100

;The height of each block
Const HEIGHT = 100

;The amount of dots in each block
Const DOTS = 100
;END CONSTANTS

;IMAGES
;Create the dotfield image
dotfieldimage = CreateImage(LENGTH,HEIGHT)
;END IMAGES

;For each dot, draw a random dot at a random location
For loop = 0 To DOTS ;For every star
;draw only on created image
SetBuffer ImageBuffer(dotfieldimage)

;Plot the dot
Plot Rnd(LENGTH), Rnd(HEIGHT)

Next

;Set buffer back to normal
SetBuffer FrontBuffer()
;END INITIALIZATION

;MAIN LOOP

;Tile the image until the user quits (presses ESC)
While Not KeyDown(1)
TileImage dotfieldimage
Wend

;END MAIN LOOP

Thanks

-Maneesh

Ross C

(Posted 2005) [#4]

The code above tiles the screen with an image. I think his may have something to do with drawing buffers. And i also assume your using blitzplus? If so, it uses the backbuffer for drawing by default.

Put in:

Flip

After your Wend.

Ross C

(Posted 2005) [#5]

Try to always use the backbuffer for drawing, then flip before the wend in the main loop. :o)

maneesh

(Posted 2005) [#6]

When I put in Flip, it works when not in fullscreen mode. However, in full screen mode, it doesn't work. I get a blank beige screen. What is going on?

Thanks

-Maneesh

Ross C

(Posted 2005) [#7]

YOu need to get rid of your setbuffer frontbuffer command. Forgot to mention that ^_^

maneesh

(Posted 2005) [#8]

When I set it to use the backbuffer, and use Flip, the screen alternates between blank beige and the star images. I still don't know what is happening.

Ross C

(Posted 2005) [#9]

Ok, here's my code :

I changed the SetBuffer FrontBuffer() command to SetBuffer BackBuffer(). And added flip.

;Set up the graphics 
Graphics 800,600 



;Seed the Random Generator 
SeedRnd MilliSecs() 

;CONSTANTS 
;The length of each block 
Const LENGTH = 100 

;The height of each block 
Const HEIGHT = 100 

;The amount of dots in each block 
Const DOTS = 100 
;END CONSTANTS 



;IMAGES 
;Create the dotfield image 
dotfieldimage = CreateImage(LENGTH,HEIGHT) 
;END IMAGES 

;For each dot, draw a random dot at a random location 
For loop = 0 To DOTS ;For every star 
;draw only on created image 
SetBuffer ImageBuffer(dotfieldimage) 

;Plot the dot 
Plot Rnd(LENGTH), Rnd(HEIGHT) 

Next 

;Set buffer back to normal 
SetBuffer BackBuffer()
;END INITIALIZATION 

;MAIN LOOP 

;Tile the image until the user quits (presses ESC) 
While Not KeyDown(1) 
TileImage dotfieldimage
Flip
Wend 

;END MAIN LOOP

maneesh

(Posted 2005) [#10]

Awesome thanks! The only thing is, when I run your program, it flips very rapidly and you can very easily see a blank beige color being alternated at the same time as the star image. Do you know why?

Ross C

(Posted 2005) [#11]

Are you using the exact same code as mine?

maneesh

(Posted 2005) [#12]

yes, i copied and pasted it directly. Is it a problem with my computer?

maneesh

(Posted 2005) [#13]

This is blitzplus, by the way

Ross C

(Posted 2005) [#14]

I'm running this in blitzplus. Seems like an odd thing to happen. Have you set, or changed anything in your graphics card drivers?

Try: (added in a cls at the top of the main loop)

;Set up the graphics 
Graphics 800,600 



;Seed the Random Generator 
SeedRnd MilliSecs() 

;CONSTANTS 
;The length of each block 
Const LENGTH = 100 

;The height of each block 
Const HEIGHT = 100 

;The amount of dots in each block 
Const DOTS = 100 
;END CONSTANTS 



;IMAGES 
;Create the dotfield image 
dotfieldimage = CreateImage(LENGTH,HEIGHT) 
;END IMAGES 

;For each dot, draw a random dot at a random location 
For loop = 0 To DOTS ;For every star 
;draw only on created image 
SetBuffer ImageBuffer(dotfieldimage) 

;Plot the dot 
Plot Rnd(LENGTH), Rnd(HEIGHT) 

Next 

;Set buffer back to normal 
SetBuffer BackBuffer()
;END INITIALIZATION 

;MAIN LOOP 

;Tile the image until the user quits (presses ESC) 
While Not KeyDown(1)

cls
TileImage dotfieldimage
Flip
Wend 

;END MAIN LOOP

Ross C

(Posted 2005) [#15]

You say beige? That's an odd color to be changing too...

maneesh

(Posted 2005) [#16]

Perfect, that fixes it completely! Any idea why the Cls command would have any effect here?

Thanks

-Maneesh

Ross C

(Posted 2005) [#17]

Might be something to do with the tileimage command drawing over the previous contents of the buffer. I can't be sure :o) Usually put a cls in anyway, to wipe the buffer clean, before i draw.