virtualPainter/paintModifier.py

import bpy
from .constants import image_name, image_width, image_height
import numpy as np
from .libs.PIL import Image
import mathutils
from timeit import default_timer as timer

def apply_color():
    start = timer()
    
    context = bpy.context
    
    paint_buffer = bpy.data.images.get(image_name)
    normal_buffer = context.scene.normal_texture_settings.texture
    custom_collection = context.scene.texture_collection_settings
    
    normal_color = context.scene.normal_color_global

    returnValue = -1
    
    if paint_buffer:
        
        # apply normal color
        if normal_buffer and normal_color != mathutils.Vector((1.0, 1.0, 1.0)):
            if paint_buffer.size[0] == normal_buffer.size[0] and paint_buffer.size[1] == normal_buffer.size[1]:
                # create arrays
                paint_mask_pixels = np.empty(len(paint_buffer.pixels), dtype=np.float32)
                paint_buffer.pixels.foreach_get(paint_mask_pixels)
                paint_mask_pixels = (paint_mask_pixels * 255).astype(np.uint8)
                target_pixels = np.empty(len(normal_buffer.pixels), dtype=np.float32)
                normal_buffer.pixels.foreach_get(target_pixels)
                target_pixels = (target_pixels * 255).astype(np.uint8)
                new_pixels = np.tile((np.array([*normal_color, 1.0], dtype=np.float32) * 255), (image_width * image_height, 1)).astype(np.uint8)

                # Convert arrays to PIL Images
                paint_mask_image = Image.frombuffer('RGBA', (image_width, image_height), paint_mask_pixels, 'raw', 'RGBA', 0, 1)
                target_image = Image.frombuffer('RGBA', (image_width, image_height), target_pixels, 'raw', 'RGBA', 0, 1)
                new_image = Image.frombuffer('RGBA', (image_width, image_height), new_pixels, 'raw', 'RGBA', 0, 1)
                r_mask, g_mask, b_mask, a_mask = paint_mask_image.split()   # separates the channels
                paint_mask_image = Image.merge("RGBA", (r_mask, g_mask, b_mask, r_mask))    # replace alpha with red

                # Blend buffers
                blended_image = Image.composite(new_image, target_image, paint_mask_image)

                # Convert blended image back to numpy array and normalize
                blended_pixels = np.array(blended_image, dtype=np.uint8).astype(np.float32) / 255.0

                # Save texture
                normal_buffer.pixels.foreach_set(blended_pixels.ravel())
                normal_buffer.update()
                
                print("Color applied")
                returnValue = 0
            
            else:
                print("Texture sizes don't match")
                returnValue = -1
        else:
            print("no normal buffer selected")
            returnValue = -1
        
        # reset paint buffer
        reset_pixels = np.empty(len(paint_buffer.pixels), dtype=np.float32)
        reset_pixels[0::4] = 0  # R
        reset_pixels[1::4] = 0  # G
        reset_pixels[2::4] = 0  # B
        reset_pixels[3::4] = 1  # A
        paint_buffer.pixels.foreach_set(reset_pixels)
        paint_buffer.update()
        
    else:
        print("Texture 'vPainter_buffer' not found")
        returnValue = -1

    end = timer()
    print(f"Time taken to apply color: {end - start:.6f} seconds")

    return returnValue

def register():
    bpy.utils.register_class(VPAINTER_OT_apply_color)

def unregister():
    bpy.utils.unregister_class(VPAINTER_OT_apply_color)