Moving forwards

[+atari2600land]

I'm trying to make a title screen for a game like the one in BMX Airmaster, but it's not going too well. I've got the engine going fine, but I need the correct pfheights to make it look like you're going forward. Would anyone like to help?

thing.bas

[SeaGtGruff]

Here's my attempt.

 

Michael

thing2.bas

[+atari2600land]

Thank you, Michael. You're the best!

[SeaGtGruff]

Thank you, Michael. You're the best!

I can get the motion smoother by adding more frames between the others. Also, I think the perspective is a bit off on the whole thing-- the farther-away lines should be a little bit closer together, and the closer lines should be a little farther apart. I'll tinker with it a little bit later tonight.

 

Michael

[SeaGtGruff]

Okay, I got the animation smoother, but I didn't try to change the overall perspective from what you originally had (4, 8, 12, 16 for the initial frame). This new version cycles between 16 frames, instead of just 4 frames. The rate of motion is a tad slower than your original version, but a little bit faster than my original version. If we refer to each drawscreen loop (about 1/60th of a second) as a "jiffy," then your original version displayed 3 frames every 30 jiffies (1 every 10 jiffies), my original version displayed 4 frames every 40 jiffies (1 every 10 jiffies), and this new version displays 16 frames every 32 jiffies (1 every 2 jiffies).

 

Michael

thing3.bas

[SeaGtGruff]

Here's my final version-- same as the last one as far as the number of frames and the perspective, but this time you can speed up or slow down by pushing the joystick up or down. I think this could be used as the start of a "Buck Rogers: Planet of Zoom" type of game.

 

Michael

thing4.bas

[+atari2600land]

Thank you Mike, you've been an immense help.

[SeaGtGruff]

Thank you Mike, you've been an immense help.

You're welcome! You always seem to come up with some pretty creative ideas. I don't know if anyone else ever thought of using the blank lines in the playfield for creating a 3D "moving forwards" effect.

 

Michael

[yuppicide]

That's great looking! Would make a good background for a space shooter of some sort. Phoenix or Galaxian type? Space Invaders type?Space Harrier even?

 

Let me ask this.. those red bars on the side.. are they a product of using pfheights? I've never used pfheights before. I don't mind the bars if they are on my title

screen, but not in my game. I would only want this effect for a title screen.

 

Do I need to ask your permission to use the code? I'm not using the lines as you have it, so it won't look like yours at all. I have something else in mind and it would be perfect to go along with a "heartbeat" sound I am trying to make........ although if those bars on the side have to be there the whole time I might reconsider.

[SeaGtGruff]

those red bars on the side.. are they a product of using pfheights?

Nope, that's from the "PF0 = $FF" command. PF0 is initialized to 0 in batari Basic, and it isn't used by the canned kernels, so that's why the playfield is only 32 pfpixels wide instead of 40. If you set PF0 to some value in your program loop, the right and left sides of the playfield (i.e., the 4 leftmost and 4 rightmost pfpixels that are controlled by PF0) will be turned on or off according to the binary pattern you set PF0 to ($FF will be all 1s, so all the PF0 pixels will be on). Since bB doesn't use PF0 to draw the playfield, whatever value you set PF0 to will stay in place for the height of the visible playfield. This is one way to add a left and right border to your playfield if you wish.

 

Do I need to ask your permission to use the code?

Don't know if you're asking atari2600land or myself, but *my* code is free for the plagiarizing. And there's nothing particularly new about atari2600land's use of pfheights to "animate" the screen-- e.g., I posted a simple example of changing the pfheights in a loop a year or two ago-- although I think this is the first time anyone did that to create a "moving forward" effect in bB. (The overall effect has been done before in commercial games.)

 

Michael

[yuppicide]

Thanks for the info!

 

I've modified it to say "Panic! Attack" which is the name of the game I am working on. It kind of animates like a heart beating and I'm going to put a thumping sound to it.

[yuppicide]

If I position a sprite over the playfield it comes out in black only. Maybe I am doing something wrong?

[SeaGtGruff]

If I position a sprite over the playfield it comes out in black only. Maybe I am doing something wrong?

The most likely causes of a black sprite are (1) you're forgetting to set the player color *inside* the screen loop, or (2) you're using one or both of the multi-colored player kernel options but something you're doing-- or not doing-- isn't quite right. Regarding the first scenario, remember that the player colors get wiped out (or rather, changed) at the bottom of the screen when the score is getting drawn, which is why you need to set the player colors *inside* the loop that draws the screen. Or if for some reason you don't want to do that, and it's okay for both players to have the same color as each (and the same color as the score), then you could just set "scorecolor" to the color you want the two players to be, which you can do *outside* the screen loop.

 

Michael