Jump to content

Photo

bB starfield effect


40 replies to this topic

#26 Yosikuma ONLINE  

Yosikuma

    Star Raider

  • 59 posts
  • Location:Independent Republic of Peoria

Posted Fri Jan 6, 2017 11:16 AM

Well damn, and here I was hoping I could finally implement my Pitfall-esque rope mechanic.  Some day ..



#27 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Sat Apr 29, 2017 4:59 PM

It looks like this effect doesn't work with the multisprite kernel, sadly.  Any chance that I'm mistaken?



#28 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Sat Apr 29, 2017 11:43 PM

Sad but correct. The multisprite kernel does a bunch of mid-screen hmoves that reset the effect, messing it up.

#29 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Mon May 1, 2017 12:27 PM

A couple more notes from my testing (and I'm happy to have any of these refuted):

 

 * This is only compatible with the standard kernel if NO_BLANK_LINES is enabled

 

 * There is no way to exploit this trick on the Flashback Portable (I guess this was too much for me to hope for given that it is based on a hardware bug.  It worked as expected in Stella, however).



#30 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Mon May 1, 2017 1:01 PM

At work right now, but AFAIK it should work without NO_BLANK_LINES. Since the missile will be under kernel control, you'll need to position the missile vertically and set it's height. The effect should show up where the missle would normally be.

#31 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Tue May 2, 2017 8:49 AM

At work right now, but AFAIK it should work without NO_BLANK_LINES. Since the missile will be under kernel control, you'll need to position the missile vertically and set it's height. The effect should show up where the missle would normally be.

 

Confirmed - thanks!

 

Hopefully this will be my last question, but it looks like this bug only applies to missile 0, and not missile 1?  I tried setting ENAM1=2 and positioning missile 1, but no luck.  My hope was to be able to use the other missile so that I could use a kernel option that took away missile 1 instead of missile 0 (player1colors) and still retain one working missile.



#32 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Tue May 2, 2017 9:22 AM

The TIA bug applies to all positionable objects. To switch my example over to missile1, just change references in the vblank routine from HMM0 to HMM1. (And change any other missile0*/ENAM0 references to missile1*/ENAM1)

#33 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Tue May 2, 2017 1:19 PM

Also confirmed - I had missed changing the assembly on my previous attempt.  Thanks again!



#34 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Tue May 2, 2017 1:58 PM

Not a problem. You're welcome. :)

#35 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Thu May 4, 2017 2:44 PM

Here's a slightly different example in case it is useful to anyone.  Use the joystick to appear to move the ship in 8 different directions.  I commented the code to show what needs to be changed to use a different missile or the ball instead in case anyone else could benefit from that.

 

Now I just need to dream up a space game where 8 directions of movement would be fun.   :)

 

Attached Files



#36 Buckaroo OFFLINE  

Buckaroo

    Space Invader

  • 19 posts
  • Location:Plymouth, UK

Posted Mon May 15, 2017 7:35 PM

This example uses both missiles on the screen at the same time and with Fixed Point 8.8 variables which can create some nice Parallax effects.

 

I've made them as big as possible and duplicated each 3 times so they cover the majority of the screen,

 

Is it possible to glitch the ball or players in the same way? I've been fiddling around with the variables but cant make them repeat.

 

 

Controls:

Select which missile to edit     ↕ Adjust by big amount     ↔ Adjust by small amount

Reset: Picks new Preset      Difficulty Switches: Toggle missile visibility

 

 

 

Attached Files



#37 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Mon May 15, 2017 7:46 PM

This example uses both missiles on the screen at the same time and with Fixed Point 8.8 variables which can create some nice Parallax effects.
 
I've made them as big as possible and duplicated each 3 times so they cover the majority of the screen,


Well done - that is some trippy stuff!


Is it possible to glitch the ball or players in the same way? I've been fiddling around with the variables but cant make them repeat.


It's technically possible, yes. I'm not sure what the issue is - I'll give it a shot in the next couple days, if you don't beat me to it.

#38 Buckaroo OFFLINE  

Buckaroo

    Space Invader

  • 19 posts
  • Location:Plymouth, UK

Posted Wed May 17, 2017 10:10 AM

It's technically possible, yes. I'm not sure what the issue is - I'll give it a shot in the next couple days, if you don't beat me to it.

 

The problem I was having was putting all 5 objects in at the same time, I was able to put one or two in before.

 

-----------------------------------------------------------------------------------------------------------------------

 

This new example uses all 5 objects in the glitch player0,player1,ball,missile0 and missile1.

 

In Visual BB I was able to make it work by keeping all of the horizontal moves on one line and calling WSYNC once

 

You can adjust the direction/speed in the same way but are unable to turn them on or off as before.

Attached Files



#39 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Sun Aug 13, 2017 11:39 AM

I've noticed that the starfield effect seems to somehow interfere with horizontal player movement, as shown in this example.  It happens regardless of whether the effect is done using either missile or the ball.  Any ideas on what is causing this, or how to work around it?

 

Attached File  vert.bas   1.63KB   9 downloads

 

Attached File  vert.bas.bin   8KB   13 downloads



#40 RevEng OFFLINE  

RevEng

    River Patroller

  • Topic Starter
  • 4,703 posts
  • Bitnik
  • Location:Canada

Posted Sun Aug 13, 2017 1:08 PM

Yeah, looks the HMOVE for the player is getting retriggered. A fairly easy fix is to add this to the beginning of the vblank routine...
 
  sta HMCLR
  sta WSYNC

Thanks for the bug report! :thumbsup: I've already updated the previous examples in this thread.

#41 kdgarris OFFLINE  

kdgarris

    Chopper Commander

  • 210 posts

Posted Sun Aug 13, 2017 2:07 PM

That fixed it - thanks!






0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users