Add SDF mode to decals

Also:
* add gen_sdf script, which converts solid color (ideally b&w) decals
  into sdf textures
* add 6 more decal slots
* add color, sdf options, alpha multiplier, tiling mode, and mask to
  decals
* add token pasting macros (MERGE) to minimize code size of new decal
  slots

1 files changed, 50 insertions, 0 deletions

diff --git a/Third_Party/gen_sdf b/Third_Party/gen_sdf
new file mode 100644
index 0000000..84677c2
--- /dev/null
+++ b/Third_Party/gen_sdf
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+
+import numpy as np
+import cv2
+import argparse
+import os
+
+def compute_sdf(img, scale_factor):
+    # Convert to binary image if not already
+    _, binary = cv2.threshold(img, 127, 255, cv2.THRESH_BINARY)
+    
+    # Compute distance transform for both foreground and background
+    dist_transform_fg = cv2.distanceTransform(binary, cv2.DIST_L2, 5)
+    dist_transform_bg = cv2.distanceTransform(255 - binary, cv2.DIST_L2, 5)
+    
+    # Combine the distance fields and scale by factor
+    sdf = (dist_transform_fg - dist_transform_bg) / scale_factor
+    
+    # Clamp values to [0, 255] range
+    sdf = np.clip(sdf + 128, 0, 255)
+    
+    return sdf.astype(np.uint8)
+
+def main():
+    parser = argparse.ArgumentParser(description='Generate SDF from black and white image')
+    parser.add_argument('input_image', help='Path to input image')
+    parser.add_argument('--scale', type=float, default=1.0, 
+                        help='Scale factor for distance (in texels)')
+    args = parser.parse_args()
+    
+    # Get input and output paths
+    input_path = args.input_image
+    filename, ext = os.path.splitext(input_path)
+    output_path = f"{filename}-sdf{ext}"
+    
+    # Read input image
+    img = cv2.imread(input_path, cv2.IMREAD_GRAYSCALE)
+    if img is None:
+        print(f"Error: Could not read image {input_path}")
+        return
+    
+    # Compute SDF with scale factor
+    sdf = compute_sdf(img, args.scale)
+    
+    # Save result
+    cv2.imwrite(output_path, sdf)
+    print(f"SDF generated and saved to {output_path}")
+
+if __name__ == "__main__":
+    main()