Python script to convert PNGs to RGBA555 image for SAGA chipset(requires PyPNG - to install call pip3 install pypng)

png2rgba555

#!/usr/bin/env python3

import png
import sys

if (len(sys.argv) < 3):
    print("Usage: png2rgba555 <input.png> <output.raw>")
    exit(1)

input_name = sys.argv[1]
output_name = sys.argv[2]

rgba = png.Reader(input_name).asRGBA()

width = rgba[0]
height = rgba[1]

pixels = list(rgba[2])
with open(output_name, "wb") as f:
    for y in range(height):
        for x in range(width):
            r = pixels[y][0 + x*4] >> 3
            g = pixels[y][1 + x*4] >> 3
            b = pixels[y][2 + x*4] >> 3
            a = int(pixels[y][3 + x*4] < 127)
            word = (a & 0x1) << 15 | (b & 0x1f) | (g & 0x1f) << 5 | (r & 0x1f) << 10
            bytes = word.to_bytes(2, byteorder='big')
            f.write(bytes)