# 🧹 Background Removal Tool

Advanced background removal for game assets with auto-detection and edge preservation.

## Features

✅ **Auto-detects background type** - White, Black, or Colored  
✅ **Preserves cartoon outlines** - Uses edge detection to keep bold strokes  
✅ **Smooth edges** - Applies subtle feathering to avoid jagged edges  
✅ **Cleans artifacts** - Removes semi-transparent pixels and gray spots  

## Usage

### Process single file:
```bash
python3 scripts/remove_bg_advanced.py path/to/image.png
```

### Process entire directory:
```bash
python3 scripts/remove_bg_advanced.py assets/images/environment/
```

### Dry run (see what would be done):
```bash
python3 scripts/remove_bg_advanced.py assets/images/ --dry-run
```

### Non-recursive (only top-level files):
```bash
python3 scripts/remove_bg_advanced.py assets/images/npcs/ --no-recursive
```

## How It Works

1. **Detection**: Samples corner pixels to determine background color
2. **Edge Preservation**: Uses gradient detection to identify and preserve outlines
3. **Removal**: Creates alpha mask based on detected background
4. **Cleanup**: Applies feathering and removes semi-transparent artifacts

## Settings

- **White backgrounds**: `tolerance=30` (removes light gray too)
- **Black backgrounds**: `tolerance=60` (aggressive - removes dark gray)
- **Colored backgrounds**: `tolerance=30` (samples from corners)
- **Edge threshold**: `magnitude > 30` (lower = more edges preserved)
- **Feathering**: `sigma=0.5` (smooth but not blurry)

## Examples

**Before (white background)**:
- Most, fence, building sprites

**Before (black background)**:
- Boss demons, dark effects, night scenes

**After**: Clean transparent PNG with preserved cartoon outlines!

## Test Results

✅ Bridge (white bg) - Perfect removal  
✅ Demon boss (black bg) - Clean removal without outline damage  
✅ Automatic detection works on all asset types  

---

**Created for:** DolinaSmrti / NovaFarma Asset Pipeline