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Proof of concept of an Apple //e double LORES demo showing an old school LENS-effect with underlying background image and PT3-music output via a MockingBoard (restricted sound quality due to the emulator used) running on a 65C02 CPU @1 MHz.

The demo shows a well-known lens simulation which is used as a dynamic mask to partially cover an underlying background image.

This little demo should provide some more learning insights on how to implement oldschool demo effects on this platform using the DOLORES-library in that complicated framework of Apple //e bank switched memory layout (neighbouring pixels are located in different memory banks).

Is it possible to do such an effect with the given system architecture?

Key Features:

  • Apple ][ LENS Demo using double LORES graphics with MockingBoard sound.
  • Simulation of  a LENS-effect in double LORES with sound:

    • Animation of a 13 x 13 pixel lens
    • Fixed precalculated distortion matrix
    • Lens X/Y-trajectory for automated lens movement 
    • User interaction possible
    • Music playback via a MockingBoard (or compatible sound card)


  • Download the DSK-image (Apple //e enhanced or better only!)!

Keyboard Commands:

  • <I,J,K,M>: Move lens by hand
  • <Q>: Quit the demo


  • Code & Gfx: SingleMalt
  • Music: unknown artist
  • Additional Advice: Dr. N. H. Cham

 System Requirements:

  • Apple //e enhanced or better
  • 65C02 CPU
  • 128 kB RAM
  • MockingBoard (no background logo animation and music without MockingBoard!)


This demo would not have reached its current point of progress without the help and software of other great guys out there. Thank you for your great software and support!

I want to point out some major contributors to this demo:

Some Technical Information:

    To be added soon...

    I am happy to discuss the technical stuff in more detail if anybody is interested!