test_texture.py

import pyredner
import torch

# Optimize four vertices of a textured patch

# Use GPU if available
pyredner.set_use_gpu(torch.cuda.is_available())

# Set up the scene using Pytorch tensor
position = torch.tensor([0.0, 0.0, -5.0])
look_at = torch.tensor([0.0, 0.0, 0.0])
up = torch.tensor([0.0, 1.0, 0.0])
fov = torch.tensor([45.0])
clip_near = 1e-2

resolution = (256, 256)
cam = pyredner.Camera(position = position,
                     look_at = look_at,
                     up = up,
                     fov = fov,
                     clip_near = clip_near,
                     resolution = resolution)

checkerboard_texture = pyredner.imread('checkerboard.exr')
if pyredner.get_use_gpu():
    checkerboard_texture = checkerboard_texture.cuda(device = pyredner.get_device())

mat_checkerboard = pyredner.Material(\
    diffuse_reflectance = checkerboard_texture)
mat_black = pyredner.Material(\
    diffuse_reflectance = torch.tensor([0.0, 0.0, 0.0],
    device = pyredner.get_device()))
materials = [mat_checkerboard, mat_black]
vertices = torch.tensor([[-1.0,-1.0,0.0], [-1.0,1.0,0.0], [1.0,-1.0,0.0], [1.0,1.0,0.0]],
                        device = pyredner.get_device())
indices = torch.tensor([[0, 1, 2], [1, 3, 2]], dtype = torch.int32,
                       device = pyredner.get_device())
uvs = torch.tensor([[0.05, 0.05], [0.05, 0.95], [0.95, 0.05], [0.95, 0.95]],
                   device = pyredner.get_device())
shape_plane = pyredner.Shape(vertices = vertices,
                             indices = indices,
                             uvs = uvs,
                             material_id = 0)
light_vertices = torch.tensor([[-1.0,-1.0,-7.0],[1.0,-1.0,-7.0],[-1.0,1.0,-7.0],[1.0,1.0,-7.0]],
                              device = pyredner.get_device())
light_indices = torch.tensor([[0,1,2],[1,3,2]], dtype = torch.int32, device = pyredner.get_device())
shape_light = pyredner.Shape(light_vertices, light_indices, 1)
shapes = [shape_plane, shape_light]
light_intensity = torch.tensor([20.0, 20.0, 20.0])
# The first argument is the shape id of the light
light = pyredner.AreaLight(1, light_intensity)
area_lights = [light]
scene = pyredner.Scene(cam, shapes, materials, area_lights)
args = pyredner.RenderFunction.serialize_scene(\
    scene = scene,
    num_samples = 16,
    max_bounces = 1)

# Alias of the render function
render = pyredner.RenderFunction.apply
# Render our target
img = render(0, *args)
pyredner.imwrite(img.cpu(), 'results/test_texture/target.exr')
pyredner.imwrite(img.cpu(), 'results/test_texture/target.png')
target = pyredner.imread('results/test_texture/target.exr')
if pyredner.get_use_gpu():
    target = target.cuda(device = pyredner.get_device())

# Perturb the scene, this is our initial guess
shape_plane.vertices = torch.tensor(\
    [[-1.1,-1.2,0.0], [-1.3,1.1,0.0], [1.1,-1.1,0.0], [0.8,1.2,0.0]],
    device = pyredner.get_device(),
    requires_grad=True)
args = pyredner.RenderFunction.serialize_scene(\
    scene = scene,
    num_samples = 16,
    max_bounces = 1)
# Render the initial guess
img = render(1, *args)
pyredner.imwrite(img.cpu(), 'results/test_texture/init.png')
diff = torch.abs(target - img)
pyredner.imwrite(diff.cpu(), 'results/test_texture/init_diff.png')

# Optimize for triangle vertices
optimizer = torch.optim.Adam([shape_plane.vertices], lr=5e-2)
for t in range(200):
    print('iteration:', t)
    optimizer.zero_grad()
    # Forward pass: render the image
    args = pyredner.RenderFunction.serialize_scene(\
        scene = scene,
        num_samples = 4,
        max_bounces = 1)
    img = render(t+1, *args)
    pyredner.imwrite(img.cpu(), 'results/test_texture/iter_{}.png'.format(t))
    loss = (img - target).pow(2).sum()
    print('loss:', loss.item())

    loss.backward()
    print('grad:', shape_plane.vertices.grad)

    optimizer.step()
    print('vertices:', shape_plane.vertices)

args = pyredner.RenderFunction.serialize_scene(\
    scene = scene,
    num_samples = 16,
    max_bounces = 1)
img = render(202, *args)
pyredner.imwrite(img.cpu(), 'results/test_texture/final.exr')
pyredner.imwrite(img.cpu(), 'results/test_texture/final.png')
pyredner.imwrite(torch.abs(target - img).cpu(), 'results/test_texture/final_diff.png')

from subprocess import call
call(["ffmpeg", "-framerate", "24", "-i",
    "results/test_texture/iter_%d.png", "-vb", "20M",
    "results/test_texture/out.mp4"])