Project Context

This project contains a browser-based fade map editor and C code showing how to use the generated fade tables in a C64 program. The target platforms are the Commodore 64 and the Commodore 64 Ultimate. It is based on an older tool and example by Zielok, described in the CSDB release at csdb.dk/release/?id=100002. The generated .fade files use the same simple format, so they can also be used with Zielok's example ASM code.

How This Editor Was Made

The browser editor was built from Zielok's original Java / Processing tool. The original JAR was decompiled and its behavior was used as the reference for the new HTML5 / JavaScript version.

Codex was used to analyze the decompiled source and build the modern HTML/JS editor. The work was done with the GPT-5.5 model using medium reasoning effort.

The Oscar64 C code in this project was created from Zielok's example ASM code. Codex helped refactor the ASM approach into C while keeping the generated .fade table format compatible.

What This Tool Is

Fade Map Editor is a small browser-based editor for creating C64 fade-in timing maps. It lets you paint a 40 x 25 screen map where each cell stores the frame number at which that character cell should begin fading in.

How To Use It

1. Load a reference picture with Load pic, if you want a visual guide under the grid.
2. Choose the current fade phase with the arrow buttons, the exact number field, or the keyboard arrow keys.
3. Paint cells on the 40 x 25 map with the left mouse button.
4. Move to the next phase and paint the next group of cells.
5. Erase cells with the right mouse button when needed.
6. Save the finished map with Save fade.

Output

The editor saves a raw 1000-byte binary .fade file. The file contains one byte per C64 screen cell, stored row by row: offset = x + y * 40. A value of 0 means the cell has no fade phase assigned. Values from 1 to 126 are fade start phases.

Controls And Features

Load fade

Loads an existing 1000-byte fade map into the grid.

Save fade

Saves the current grid as a binary .fade file.

Load pic

Loads an image as a stretched 800 x 500 reference background behind the grid.

Clear fade

Clears all assigned cells and returns the map to zeros.

Undo / Redo

Steps backward or forward through recent paint, erase, load, and clear changes.

Phase

The number painted into cells. Use < and > for one step, << and >> for ten steps, or enter an exact value.

Keyboard

Left Arrow selects the previous phase. Right Arrow selects the next phase. Hold Shift with either arrow to move by ten phases.

Show values

Shows or hides the numeric phase labels inside painted cells.

Grid

Shows or hides the 40 x 25 grid overlay.

Pic opacity

Changes how strongly the loaded reference picture appears under the map.

Dark mode

Switches between the default light theme and a dark gray workspace theme.