Commodore 128 Alive!

Commodore 128 => 128 programmers => Topic started by: Goodwell on June 09, 2025, 07:20 AM

Title: VDC Soft-Sprite Demo
Post by: Goodwell on June 09, 2025, 07:20 AM
Here's a small, interactive demo that allows you to move a softsprite across a screen in 160x100 resolution (64 kB VRAM required).

pasted-from-clipboard.png

Use keys IJKL to move the ghost, X exits the program.
You can also list the sourcecode, which shows that the main loop is a regular basic program.

This uses the VDC-Basic extension which focuses on leveraging on the hardware capabilities of the VDC-Chip (block copy and block fill).
In 160x100, one byte holds two pixels.
Fully transparent bytes are skipped from block copy.
Bytes with one transparent pixel require a slow OR operation.

Still, drawing the softsprite only takes about 2 jiffies at 2 MHz.
This is using double buffering, so there's no flicker.

Looking at this, I think the C128 could have been capable of running DOS ports that never made it to the C64. Or ports that really were beyond the C64's strengths (eg Ultima VI)

You can find more information about VDC-Basic here: https://github.com/the8bittheory/vdc-basic
Title: Re: VDC Soft-Sprite Demo
Post by: RobertB on June 25, 2025, 11:57 AM
Oh, that is nice!  Thanks!

On the road after the Pacific Commodore Expo NW 2025,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan
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