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Screen Tests!

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tschak909

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I am slowly progressing. I have the first DLI routine set in place to set the colors. Had to use a chain of routines each modifying the DLI vector at the end of each pass. Because I had to make four distinct color changes, I decided to hard-code them into the routine, so that I could minimise the number of cycles being done. I will be modifying the look of the screen layout from here, but now I have something i can work with and mould to look the way I want it to look.

 

You may have noticed I used a narrow playfield. I did this to be more in line with the aspect ratio of the original game, as well as to give me more cycles per line to do color palette changes. I am glad the idea I had worked. I just need to tweak the colors, maybe make them brighter, and perhaps play with the top score line a bit. I wanted to keep it nice and readable, but if I want color, I'll probably have to use an antic mode 4 line there too, I just wish I could have a border around the whole thing..but I guess that's out of the question....

 

I have hardcoded and filled the screen with invaders right now, just so i can get a sense of the space of the screen, there will not be this many invaders on screen at once, I know they need space to breathe and move around....

 

The only real bug I had, was that I had one too few DLI instructions defined in the display list, so the interrupt vectors were being cycled through, one less than should be, giving an interesting stair-step effect, whoops :-D

 

Now i will design the character for the player....

 

Screenshots posted below:

 

post-2607-1092480228_thumb.png <-- Before any DLI treatment, totally monochrome

 

post-2607-1092524948_thumb.png <-- After the DLI treatment, technicolor!

 

-Thom

 

I have also included a dos 2 image with the current source.

 

Disk Image: post-2607-1092542264_thumb.png

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So you are using char graphics; how will you smoothly move objects around the screen? Or will the invaders move only in 1-char jumps?

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I will try to use the smooth scrolling registers to move the invaders.

 

Another approach to moving invaders is to have several different versions of the invader characters shifted by different amounts. As a simple example, if the invaders are 12 pixels wide and have two animation frames, you could have one animation frame drawn using the leftmost 12 pixels in a pair of characters and the other drawn using the rightmost 12. If there are four animation frames, then you could have invaders up to 10 pixels wide drawn in a two-character space or 18 pixels wide using a three-character space.

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I will try to use the smooth scrolling registers to move the invaders.

 

Another approach to moving invaders is to have several different versions of the invader characters shifted by different amounts. As a simple example, if the invaders are 12 pixels wide and have two animation frames, you could have one animation frame drawn using the leftmost 12 pixels in a pair of characters and the other drawn using the rightmost 12. If there are four animation frames, then you could have invaders up to 10 pixels wide drawn in a two-character space or 18 pixels wide using a three-character space.

The problem with that is you can run out of characters real quick; I think the A800 only has 128 chars to work with.

 

Depends on what you're doing, I suppose.

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I chose to load multiple character sets into memory, and change the CHBAS pointer at vertical blank. It takes up more memory, yes, but it will allow me to provide smooth animation for everything without sacrificing too many cpu cycles.

 

-Thom

 

I will try to use the smooth scrolling registers to move the invaders.

 

Another approach to moving invaders is to have several different versions of the invader characters shifted by different amounts. As a simple example, if the invaders are 12 pixels wide and have two animation frames, you could have one animation frame drawn using the leftmost 12 pixels in a pair of characters and the other drawn using the rightmost 12. If there are four animation frames, then you could have invaders up to 10 pixels wide drawn in a two-character space or 18 pixels wide using a three-character space.

The problem with that is you can run out of characters real quick; I think the A800 only has 128 chars to work with.

 

Depends on what you're doing, I suppose.

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