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SpiceWare's Blog



NFL Sunday Ticket without satellite

Posted by SpiceWare, in DVR Project 16 July 2014 · 144 views

If true, this might help some people sitting on the fence decide to cut the cord.
 


step 14 - add animation

Posted by SpiceWare, in Collect 14 July 2014 · 138 views

Static images that just slide around the screen work OK, but we can do better - so for this update we'll add a couple new images so we can animate the players as they run around the arena.

 
While you can have as many frames of animation as you'd like, the code is most efficient if the number of frames is a power of 2 (2, 4, 8, 16, etc). The code t...


step 13 - add sound effects

Posted by SpiceWare, in Collect 13 July 2014 · 125 views

A quiet game is playable, but it's more fun with sound. TIA produces 2 channel sound. The channels are known as channel 0 and channel 1. There are 3 registers for each channel to control the sound produced:
AUDC0, AUDC1 - Control of the channel, specifies the type of sound to generate. Values range from 0 to 15, though some values produce the same type of...


step 12 - add the missile objects

Posted by SpiceWare, in Collect 12 July 2014 · 121 views

The 2LK has been revised to display both missile objects.  Missile objects do not support Vertical Delay, so there's no need to prime ENAM0 or ENAM1.
ArenaLoop: ; 17 - (currently 17 from bpl ArenaLoop) ; continuation of line 2 of the 2LK ; this precalculates data that's used on line 1 of the 2LK tya ; 2...


step 11 - add the ball object

Posted by SpiceWare, in Collect 11 July 2014 · 116 views

The 2LK has been revised to display the ball object. Like player0, the ball needs to be primed before the ArenaLoop begins:
   ; prime ENABL so ball can appear on topmost scanline of Arena        ldx #1              ; 2  2 - D1=0, so ball will be off         l...


step 10 - "Random Numbers"

Posted by SpiceWare, in Collect 10 July 2014 · 157 views

And yes, those are air quotes   ;)
 
Inside the Atari (and computers in general), there's no such thing as a Random Number.  We can, however, simulate random numbers by using a Linear Feedback Shift Register .  The LFSR we're going to use was posted by batari , it's a rather slick bit of code in that it can be either an 8-bit or 1...


step 9 - Game Variations

Posted by SpiceWare, in Collect 09 July 2014 · 194 views

It's common for Atari games to have a number of game variations.  To simplify the logic, the variations are usually driven by individual bits and/or groups of bits within a single byte that holds the game variation. A good example of that would be Space Invaders - check out the game matrix from the manual:

 
A byte is comprised of 8 bits, usu...


June Savings

Posted by SpiceWare, in DVR Project 08 July 2014 · 131 views

No content purchased in June so $151 in savings. Cumulative savings is now at $2217.

While I did buy a Blu-ray drive, it's for the Mac Pro I plan to purchase sometime during the next few months. As such, I'm not counting its price towards the DVR setup.

I did, however, buy a couple iOS software apps.   The InstaTV Pro software I'd purchased back in...


step 8 - Select and Reset support

Posted by SpiceWare, in Collect 07 July 2014 · 194 views

For this update we're adding initial support for the Select and Reset buttons.  For this we're adding a new RAM variable called GameState to keep track of "Game Active" vs "Game Over".
    ; D7, 1=Game Active, 0=Game OverGameState:      ds 1    ; stored in $A7  
 
We're going to use D7 to denote the state...


step 7 - draw the playfield

Posted by SpiceWare, in Collect 06 July 2014 · 137 views

For this update, we're going to modify the Arena Loop to draw the Arena using the playfield.  The new Arena loop has these new changes:
 
ArenaLoop: ; 27 - (currently 7 from bpl ArenaLoop) tya ; 2 29 - 2LK loop counter in A for testing and #%11 ; 2 31 - test for every 4th time through t...






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