README.md

Adding a bunny lit with an environment map to a background using Blender's Cycles renderer.

run.py

import sys
import os
import random
import shutil
from os.path import basename as bn

PACKAGE_PARENT = '../..'
SCRIPT_DIR = os.path.dirname(os.path.realpath(os.path.join(os.getcwd(), os.path.expanduser(__file__))))
sys.path.append(os.path.normpath(os.path.join(SCRIPT_DIR, PACKAGE_PARENT)))

from hdrio import imwrite, imread
import numpy as np
from scipy.misc import imresize


output_dir = "renders"
os.makedirs(output_dir, exist_ok=True)

blender_exec = shutil.which('blender')
blender_scene = os.path.join(SCRIPT_DIR, "scene.blend")
python_script = os.path.join(SCRIPT_DIR, "scene.py")
def runBlender():
    os.system("{} --background {} --python {}".format(blender_exec, blender_scene, python_script))


def addBackground(im, background):
    comp = imresize(im, background.shape[:2]).astype('float32') / 255.

    alpha = comp[:,:,3]
    alpha3_n = np.tile(1 - alpha[:,:,np.newaxis], [1, 1, 3])
    alpha3_p = np.tile(alpha[:,:,np.newaxis], [1, 1, 3])

    return background[:,:,:3]*alpha3_n + comp[:,:,:3]*alpha3_p


def doRenderAndCompose(envmap_fn, background_fn):
    outfile = os.path.join(output_dir, '{}_{}.png'.format(bn(envmap_fn), bn(background_fn)))
    if os.path.exists(outfile):
        print('Already done: ', outfile)
        return
    
    shutil.copyfile(envmap_fn, './envmap.exr')

    runBlender()
    render = imread('out.png')
    background = imread(background_fn)
    comp = addBackground(render, background)

    return comp


def main():
    # Warning: Filenames should not be in ("out.png", "out_groundplane.png")
    # Change filename here (for a loop maybe?)
    envmap_filename = "mon_envmap.exr"
    background_filename = "mon_background.png"
    

    #render = doRenderAndCompose(envmap_filename, background_filename)
    render = imread('out.png')
    background = imread(background_filename)
    render = addBackground(render, background)

    if render is not None:
        imwrite(render, os.path.join(output_dir, '{}_{}.png'.format(bn(envmap_filename), bn(background_filename))))
        groundplane_fn = [x for x in os.listdir('./out_groundplane/') if x.endswith('.png')][0]
        shutil.move(os.path.join('./out_groundplane/', groundplane_fn), os.path.join(output_dir, '{}_{}_groundplane.png'.format(bn(envmap_filename), bn(background_filename))))
        shutil.rmtree('./out_groundplane/')


if __name__ == '__main__':
    main()

scene.blend

scene.py