Crisp art on ColecoVision... what's the secret?

[Jess Ragan]

After the announcement of a BASIC compiler for the ColecoVision, I got the urge to mess with the system and see what I could do with it. I haven't given CVBasic more than a cursory look, but I did find Tursi's graphics converter and ran a few test drawings through it.

 

The original picture, based on Heiankyo Alien, is on the right. The ColecoVision version is on the left, and is littered with artifacting and striping that leaves the image looking compromised. What's the best way to limit or eliminate the artifacting entirely? I saw the title screen for Nanochess' game Camelot Knights, and that image was heavily shadowed, but also crisp, with little evidence of the ColecoVision's visual limitations.

 

What's the trick to making images pop on the ColecoVision? Heavy outlining seems to help, but are there any other tips that will reduce color clash and result in a more professional look?

[+nanochess]

The VDP main limitation is having only two colors for each 8 pixel row.

 

My first step when adapting images is centering faces on the 8x8 grid to get the most possible details in special in the eyes.

 

When the image has outline, almost always, it has to disappear because it is a third color. I use the inner colors to fill the outline. Or I keep the outline if it separates areas with the same color (it qualifies as only two colors)

 

Sometimes I need to "correct" curves so the 8x8 artifacts aren't so noticeable. Also, I take advantage of shadow colors (making areas bigger or smaller) to avoid when possible having 3 colors in the same 8 pixels.

[Jess Ragan]

Thanks for the advice. I'll have to figure out if I can make this work with my art style.

 

Also, it's weird that I can just drag and drop any old drawing I've done, and Tursi's software spits out a ColecoVision ROM. The original CV designers probably wished they had that kind of power at their fingertips!

[+nanochess]

15 hours ago, Jess Ragan said:

Thanks for the advice. I'll have to figure out if I can make this work with my art style.

 

Also, it's weird that I can just drag and drop any old drawing I've done, and Tursi's software spits out a ColecoVision ROM. The original CV designers probably wished they had that kind of power at their fingertips!

My tools aren't drag&drop, but you can do same in three commands:

 

tmscolor -b image.bmp image.bas

cvbasic image.bas image.asm

gasm80 image.asm -o image.rom

 

Btw, there is another recent image where I had to make some adaptations to get it nice (also I got some help of the artists in the 2nd pass):

 

https://github.com/nanochess/240pTestSuite_colecovision/blob/master/donna.bmp

 

 

[Falonn]

1 hour ago, nanochess said:

Btw, there is another recent image where I had to make some adaptations to get it nice...

This kind of technology-limited artwork has always been amazing to me.  When it's done right it looks effortless, but when you take a look with the 8-pixel delimiters, you can see the intricate dance between form and palette:

It's already hard enough to create nice looking art without having one of your hands tied behind your back!  I suppose the same appreciation goes for all of the platform limitations: game soundtracks that fit in just a couple channels (that you remember and will hum/whistle for the rest of your life), entire games that are smaller than the above PNG file...

 

At least for me, the kind of artistry, ingenuity, and craftsmanship required is half the appeal of the retro-computing hobby.  This stuff is so cool.

[Jess Ragan]

I mean, yeah. Nano ported a Dreamcast diagnostic tool to the ColecoVision, and you know that couldn't have been easy at all.

[artrag]

In some cases it is convenient to stretch horizontally a bit the pictures to reduce the number of colors in the same line of 8 pixels.

For static images the sprites can add a lot of details where you need to break the two colors rule.

The converter by nanochess does an automagic placement of sprites to mask errors, anyway they are limited to 4 per line and can have a single color each. So it if matter of trade off also in this case 

[Pixelboy]

14 hours ago, Falonn said:

When it's done right it looks effortless, but when you take a look with the 8-pixel delimiters, you can see the intricate dance between form and palette:

I'm seeing some 8-pixel lines with three colors (look in the last column on the right side, there's yellow + black + light yellow on some lines near the bottom) which leads me to believe that there are "color-bleed masking sprites" used in that particular picture. 

 

[+nanochess]

1 hour ago, Pixelboy said:

I'm seeing some 8-pixel lines with three colors (look in the last column on the right side, there's yellow + black + light yellow on some lines near the bottom) which leads me to believe that there are "color-bleed masking sprites" used in that particular picture. 

 

That's right. You have eagle eyes.

 

This image uses magic sprites, but only two maximum in a horizontal row because there is a kind of cursor over the image made by 2x2 sprites.

[Jess Ragan]

Is there a pixel art program that will take an image and offer 8x8 gridlines, so you can zoom in, zoom out, and make changes as appropriate?

[Tursi]

So far as using my conversion tool, it's more art than science.

 

The first thing I usually say is that every single pixel matters - if you have black bars, you are wasting space. Zoom that picture in and crop the edges using the 'fill mode' (usually to Middle). We do lose a bit on this image, but using the Up and Down buttons you can shift it a bit (hold shift and/or control for bigger steps).

 

Atkinson seemed to do the best job for me, though there's a lot of horizontal clash. The 'right' and 'left' buttons will let you shift the image 7 pixels either way to try and minimize clash. Usually the dither can hide most of it, and this causes some wraparound issues anyway.

 

I turned the Gamma down to get stronger colors - I think the result is okay but it depends on how important the original colors are. You can also use "Max Color Shift" to change how much the system is allowed to tweak colors towards the Coleco palette... I tend to keep it at 5%

 

I wrote a post covering all the different opens and how they affect the conversion:
 

 

 

 

[+nanochess]

I had to give it a try. I used Windows XP and Paint .NET.

 

The first step is having a crisp outline. I've made several passes changing the brightness to extract barely seen parts of the outline (like the tree in the background or the shape of the hills).

Then colorizing the inner portions of the drawing, closing paths as necessary to not paint outside the shapes.

 

 

Finally, using the warnings emitted by TMSColor I proceeded to remove as possible the color collisions. In the end, I used the magic sprites option (-m) and I had to adapt the outlines as possible. Sometimes I had to remove altogether the black lines. Notice how I adapted the monster's arms curves and adjusted the teeth. The nose, mouth, ear, and eyes of the bear had to be adjusted to not have so many sprites in the same row. The use of the black background helped to preserve the shapes at the top.

 

I've attached the final files generated by TMSColor. 26 sprites are used to cover areas of three colors.

 

heyalien.bmp heyalien.bas heyalien.rom

[Jess Ragan]

Well holy crap! Thanks! This does look quite a bit nicer with a lot of image processing.