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import pydiffvg | |
import torch | |
import skimage | |
pydiffvg.set_print_timing(True) | |
# Use GPU if available | |
pydiffvg.set_use_gpu(torch.cuda.is_available()) | |
canvas_width, canvas_height = 256, 256 | |
num_control_points = torch.tensor([2]) | |
points = torch.tensor([[120.0, 30.0], # base | |
[150.0, 60.0], # control point | |
[ 90.0, 198.0], # control point | |
[ 60.0, 218.0]]) # base | |
thickness = torch.tensor([10.0, 5.0, 4.0, 20.0]) | |
path = pydiffvg.Path(num_control_points = num_control_points, | |
points = points, | |
is_closed = False, | |
stroke_width = thickness) | |
shapes = [path] | |
path_group = pydiffvg.ShapeGroup(shape_ids = torch.tensor([0]), | |
fill_color = None, | |
stroke_color = torch.tensor([0.6, 0.3, 0.6, 0.8])) | |
shape_groups = [path_group] | |
scene_args = pydiffvg.RenderFunction.serialize_scene(\ | |
canvas_width, canvas_height, shapes, shape_groups) | |
render = pydiffvg.RenderFunction.apply | |
img = render(256, # width | |
256, # height | |
2, # num_samples_x | |
2, # num_samples_y | |
0, # seed | |
None, # background_image | |
*scene_args) | |
# The output image is in linear RGB space. Do Gamma correction before saving the image. | |
pydiffvg.imwrite(img.cpu(), 'results/single_open_curve_thickness/target.png', gamma=2.2) | |
target = img.clone() | |
# Move the path to produce initial guess | |
# normalize points for easier learning rate | |
points_n = torch.tensor([[100.0/256.0, 40.0/256.0], # base | |
[155.0/256.0, 65.0/256.0], # control point | |
[100.0/256.0, 180.0/256.0], # control point | |
[ 65.0/256.0, 238.0/256.0]], # base | |
requires_grad = True) | |
thickness_n = torch.tensor([10.0 / 100.0, 10.0 / 100.0, 10.0 / 100.0, 10.0 / 100.0], | |
requires_grad = True) | |
stroke_color = torch.tensor([0.4, 0.7, 0.5, 0.5], requires_grad=True) | |
path.points = points_n * 256 | |
path.stroke_width = thickness_n * 100 | |
path_group.stroke_color = stroke_color | |
scene_args = pydiffvg.RenderFunction.serialize_scene(\ | |
canvas_width, canvas_height, shapes, shape_groups) | |
img = render(256, # width | |
256, # height | |
2, # num_samples_x | |
2, # num_samples_y | |
1, # seed | |
None, # background_image | |
*scene_args) | |
pydiffvg.imwrite(img.cpu(), 'results/single_open_curve_thickness/init.png', gamma=2.2) | |
# Optimize | |
optimizer = torch.optim.Adam([points_n, thickness_n, stroke_color], lr=1e-2) | |
# Run 200 Adam iterations. | |
for t in range(200): | |
print('iteration:', t) | |
optimizer.zero_grad() | |
# Forward pass: render the image. | |
path.points = points_n * 256 | |
path.stroke_width = thickness_n * 100 | |
path_group.stroke_color = stroke_color | |
scene_args = pydiffvg.RenderFunction.serialize_scene(\ | |
canvas_width, canvas_height, shapes, shape_groups) | |
img = render(256, # width | |
256, # height | |
2, # num_samples_x | |
2, # num_samples_y | |
t+1, # seed | |
None, # background_image | |
*scene_args) | |
# Save the intermediate render. | |
pydiffvg.imwrite(img.cpu(), 'results/single_open_curve_thickness/iter_{}.png'.format(t), gamma=2.2) | |
# Compute the loss function. Here it is L2. | |
loss = (img - target).pow(2).sum() | |
print('loss:', loss.item()) | |
# Backpropagate the gradients. | |
loss.backward() | |
# Print the gradients | |
print('points_n.grad:', points_n.grad) | |
print('thickness_n.grad:', thickness_n.grad) | |
print('stroke_color.grad:', stroke_color.grad) | |
# Take a gradient descent step. | |
optimizer.step() | |
# Print the current params. | |
print('points:', path.points) | |
print('thickness:', path.stroke_width) | |
print('stroke_color:', path_group.stroke_color) | |
# Render the final result. | |
path.points = points_n * 256 | |
path.stroke_width = thickness_n * 100 | |
path_group.stroke_color = stroke_color | |
scene_args = pydiffvg.RenderFunction.serialize_scene(\ | |
canvas_width, canvas_height, shapes, shape_groups) | |
img = render(256, # width | |
256, # height | |
2, # num_samples_x | |
2, # num_samples_y | |
202, # seed | |
None, # background_image | |
*scene_args) | |
# Save the images and differences. | |
pydiffvg.imwrite(img.cpu(), 'results/single_open_curve_thickness/final.png') | |
# Convert the intermediate renderings to a video. | |
from subprocess import call | |
call(["ffmpeg", "-framerate", "24", "-i", | |
"results/single_open_curve_thickness/iter_%d.png", "-vb", "20M", | |
"results/single_open_curve_thickness/out.mp4"]) | |