The backgrounds in Double Dragon

[tdp]

I was just wondering how the backgrounds in Double Dragon are created? they are very detailed, and very colourful, and most importantly, solid. Are they using sprites in an area that is not changed once drawn, as the players cannot move to that part of the screen, so that part of the screen never needs to be updated once drawn? Batari's playfield options are much more limited than this from what I can see, and from what I have been able to produce.

 

[ZackAttack]

Are you aware of the debug colors mode in the Stella emulator? (alt + , on PC) That feature and enabled/disabling individual players and missiles should make it easy to see how any game is put together visually.

[tdp]

Thanks, ZackAttack. I will check that out.

[+SpiceWare]

Yep, use the debugger colors. Game:

 

Debug:

 

Hit ~ to enter the debugger then the select the TIA tab to see the coloration for each object, such as P0 (player 0) is red

 

So looking at that you can see things like:

• P0 = Player 0, (aka sprite 0) for garage door, inside of windows, player's figure on the left, etc.
• M0 = Missile 0, draws 3 vertical lines in the left gauge
• P1 = Player 1, draws columns(?) and enemy figures on right, etc.
• M1 = Missile 1, a few scanlines of the black strip down the left, draws 3 vertical lines in the right gauge
• PF = Playfield, draws the window frame, visible bricks, etc.
• BL = Ball, not used
• BK = Background, draws the blue wall, sidewalk, and street, etc.
• HM = HMOVE, most of black strip down the left (a side effect of reusing the objects on the 2600)

[tdp]

Thanks Darrell - will spend sometime later on today on this.

[CDS Games]

The backgrounds are drawn in 3 main sections. So in the screen that Darrell posted, the little top windows are part of the first section--two sprites, playfield, and background colors. Then the second "main" section that has the garage door and the columns. Again it uses two sprites, playfield, and background colors. And then the third "sidewalk" section that just consists of background colors. Since the action doesn't take place up that high, the program can spend the available cycles just drawing each section in great detail.

 

Then below the sidewalk where the actual game play takes place, the background switches to a single invariant color.

 

It's very cleverly done, and I agree with you....the background graphics on this title are excellent. It's just frustrating that the player characters looked shoddy in comparison.