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Adding 256 color mode with user defined transparency

by Alain Labrie · in Torque Game Builder · 10/23/2010 (3:05 pm) · 6 replies

In an attempt to save memory, I am investigating converting art assets to 256 color and using magenta as the transparent color. It's a little old school, but a 256 color image can use as little as 1/4 the ram of a RGBA, and this would make it possible to have up to 4 times more sprites for the same memory footprint.

So has anyone done this for TGB,iTGB? Please don't say "key mode" since that only serves to delineates rectangular images for each other. I have been searching but so far nothing...
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Torque 3D Owner Ronny Bangsund
Torque Cheerleaders
#1
10/23/2010 (4:18 pm)
If you want to save memory, you can save more with PVR. Indexed images with 1-bit alpha are possible with GIF, but the PVR way still saves more VRAM. I've found it works well with the 2D art packs sold on this site, but not particularly well with uniform surfaces and gradients.

Torque Owner Alain Labrie
Ware-Wolf Games
#2
10/23/2010 (4:29 pm)
I tried PVR in the past on sprite sheets, and the results were less then great. it added a lot of garbage pixels in the transparent areas...

Torque 3D Owner Ronny Bangsund
Torque Cheerleaders
#3
10/23/2010 (4:36 pm)
It shouldn't be adding garbage at all in transparent areas, so that's weird. At least things look alright when I use Apple's texturetool.

Torque Owner Alain Labrie
Ware-Wolf Games
#4
10/23/2010 (4:42 pm)
I have not tried Apple's texture tool, I have been using the tool that ships with iTorque2D (iTGB), can't recall what it's called... but it adds garbage around the edges, probably does not like the blended edges. Maybe I will try it with a more solid pixel border.

Torque 3D Owner Ronny Bangsund
Torque Cheerleaders
#5
10/23/2010 (4:46 pm)
To quote a doctor: Yeah, stop doing that :)

There is a certain threshold you need to adjust for, too. I think every sprite needs at least a pixel or two on each edge to not suffer from colour bleed. It *is* capable of proper transparency, and the sprites in the Adventure Kit have very generous transparent areas around most cells for their animated characters. If the sprites are touching, PVR will do a very bad job.

On desktop it doesn't matter; you have craploads of RAM even on the cheapest piece of crap "netbook" laptop-wannabe :)

Torque Owner Alain Labrie
Ware-Wolf Games
#6
10/23/2010 (5:27 pm)
@Ronny
When I said that "it added garbage around the edges", I did not mean around the cell border, but I meant on the outline edges of the sprites. i.e. around the legs or arms...