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Banding Effect (Color Quantization)

The Banding effect (or color depth reduction) is an artistic filter that intentionally reduces color precision to create styles ranging from retro computing to technical diagrams.

🚀 Quick Overview

The system offers 5 distinct modes, cycled through key '7'. Each mode uses a different mathematical approach to compress the color space.

Graphviz Diagram

🎨 The 5 Artistic Styles

1. Pop Art (Linear)

The simplest mode. It divides the color space into equal steps. - Usage: For a "Cel-shaded" or "Comic book" look. - Math: \f[ result = \frac{\lfloor color \cdot levels \rfloor}{levels} \f]

2. Retro Computing (Dithered)

Uses a Bayer 4x4 matrix to simulate intermediate shades via a threshold grid. - Usage: Macintosh, GameBoy, or old CGA monitor style. - Principle:

Graphviz Diagram

3. Analog (Perceptual)

Applies a gamma curve before quantization to preserve more detail in dark areas. - Usage: "Vintage video sensor" look. - Advantage: Avoids massive black blobs in shadows. \f[ result = \left( \frac{\lfloor color^{\gamma} \cdot levels \rfloor}{levels} \right)^{\frac{1}{\gamma}} \f]

4. CGA/VGA Style (Channel)

Reduces the precision of each RGB channel independently. - Usage: Simulate limited hardware palettes (e.g., 8 red levels, 8 green, 4 blue).

5. Blueprint (Luminance)

Quantizes the perceived luminance of the image, then applies a color tint. - Usage: Technical blueprints, holograms, futuristic interfaces.

⚙️ Parameters (PostProcessPreset)

Parameter Description
mode Style selector (0 to 4).
levels Number of color levels (e.g., 2.0 = Black/White).
dither_strength Grain intensity (Mode 1 only).
perceptual_gamma Contrast curve (Mode 2 only).
channel_levels RGB channels (Mode 3) or Tint Color (Mode 4).

🛠 Technical Integration

The effect is implemented in the PBR pipeline via an optimized Uber-shader.

Graphviz Diagram