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Help Assembly 2600 Black Screen New

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#1 Heroes & Shadows OFFLINE  

Heroes & Shadows

    Star Raider

  • 51 posts

Posted Tue Oct 9, 2018 7:59 PM

Hi,

 

I am having an issue with getting a simple display going. What's supposed to happen is a brown smiley face is supposed to appear.on the screen. Instead, all I get is a black screen with nothing being shown. I tried using the debugger, but couldn't figure out what was going on as it kept getting stuck on the line checking to see if the players y position is equal to the current scanline until the overscan period.

 

Source Code: https://www.dropbox....source.asm?dl=0



#2 Karl G OFFLINE  

Karl G

    Dragonstomper

  • 656 posts

Posted Tue Oct 9, 2018 8:46 PM

Just at a first glance, I am noticing this:

; ***********************
; Initialisation
; ***********************
lda #01 ; decimal color code for brown
sta COLUP0 ; set player's graphic color

This is black on a default background of black.  I'm assuming NTSC based on the timings, so you probably want maybe something like $F4 here for brown, depending on the desired shade.  See this page for color reference:

 

http://www.qotile.ne.../tia_color.html



#3 Karl G OFFLINE  

Karl G

    Dragonstomper

  • 656 posts

Posted Tue Oct 9, 2018 8:52 PM

I assembled your source myself and ran it under Stella, turning on the "debug colors" option (Control-Comma or Command-Comma depending on your platform).  Your sprite is there, but just invisible due to color.

 

Screen Shot 2018-10-09 at 10.47.53 PM.png



#4 Heroes & Shadows OFFLINE  

Heroes & Shadows

    Star Raider

  • Topic Starter
  • 51 posts

Posted Tue Oct 9, 2018 10:06 PM

Just at a first glance, I am noticing this:

; ***********************
; Initialisation
; ***********************
lda #01 ; decimal color code for brown
sta COLUP0 ; set player's graphic color

This is black on a default background of black.  I'm assuming NTSC based on the timings, so you probably want maybe something like $F4 here for brown, depending on the desired shade.  See this page for color reference:

 

http://www.qotile.ne.../tia_color.html

Thanks for the handy link, I was looking at the one here: https://atariage.com...01/06happy.html which is very different than the one you linked to.

 

I assembled your source myself and ran it under Stella, turning on the "debug colors" option (Control-Comma or Command-Comma depending on your platform).  Your sprite is there, but just invisible due to color.

 

attachicon.gifScreen Shot 2018-10-09 at 10.47.53 PM.png

 

That's actually very good to know. As I said I 'm very new to this so I'm starting very slow, and working my way up. This is actually my third "step", the second was just getting a basic skeleton working and the first setting up a working development toolchain. Is there a tutorial for the Stella debugger that i can use to learn how to use it better maybe on Youtube?



#5 Karl G OFFLINE  

Karl G

    Dragonstomper

  • 656 posts

Posted Wed Oct 10, 2018 12:02 PM

I'm guessing that you are aware of the the documentation page for the debugger, but I'll give you that link just in case.  I hadn't heard of any tutorials myself, though searching for "stella debugger" on YouTube showed a couple of results from the same user.  If you try them, I'd be interested to hear how helpful they were:

 

 

 

(Based on seeing "Mr. Celery" in the thumbnail, I wonder if these were made by our own atari2600land).



#6 SvOlli OFFLINE  

SvOlli

    Chopper Commander

  • 214 posts
  • Location:Hannover, Germany

Posted Wed Oct 10, 2018 2:13 PM

Thanks for the handy link, I was looking at the one here: https://atariage.com...01/06happy.html which is very different than the one you linked to.

 

You just read that table wrong. The color you assumed to be $01 is $10. On top is the base color, which is the first digit, The brightness is the second digit.







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