# Copyright (c) Facebook, Inc. and its affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.


import unittest

import numpy as np
import torch
from common_testing import get_tests_dir
from PIL import Image
from pytorch3d.renderer.cameras import FoVPerspectiveCameras, look_at_view_transform
from pytorch3d.renderer.mesh.rasterizer import MeshRasterizer, RasterizationSettings
from pytorch3d.renderer.points.rasterizer import (
    PointsRasterizationSettings,
    PointsRasterizer,
)
from pytorch3d.structures import Pointclouds
from pytorch3d.utils.ico_sphere import ico_sphere


DATA_DIR = get_tests_dir() / "data"
DEBUG = False  # Set DEBUG to true to save outputs from the tests.


def convert_image_to_binary_mask(filename):
    with Image.open(filename) as raw_image:
        image = torch.from_numpy(np.array(raw_image))
    mx = image.max()
    image_norm = (image == mx).to(torch.int64)
    return image_norm


class TestMeshRasterizer(unittest.TestCase):
    def test_simple_sphere(self):
        device = torch.device("cuda:0")
        ref_filename = "test_rasterized_sphere.png"
        image_ref_filename = DATA_DIR / ref_filename

        # Rescale image_ref to the 0 - 1 range and convert to a binary mask.
        image_ref = convert_image_to_binary_mask(image_ref_filename)

        # Init mesh
        sphere_mesh = ico_sphere(5, device)

        # Init rasterizer settings
        R, T = look_at_view_transform(2.7, 0, 0)
        cameras = FoVPerspectiveCameras(device=device, R=R, T=T)
        raster_settings = RasterizationSettings(
            image_size=512, blur_radius=0.0, faces_per_pixel=1, bin_size=0
        )

        # Init rasterizer
        rasterizer = MeshRasterizer(cameras=cameras, raster_settings=raster_settings)

        ####################################
        # 1. Test rasterizing a single mesh
        ####################################

        fragments = rasterizer(sphere_mesh)
        image = fragments.pix_to_face[0, ..., 0].squeeze().cpu()
        # Convert pix_to_face to a binary mask
        image[image >= 0] = 1.0
        image[image < 0] = 0.0

        if DEBUG:
            Image.fromarray((image.numpy() * 255).astype(np.uint8)).save(
                DATA_DIR / "DEBUG_test_rasterized_sphere.png"
            )

        self.assertTrue(torch.allclose(image, image_ref))

        ##################################
        #  2. Test with a batch of meshes
        ##################################

        batch_size = 10
        sphere_meshes = sphere_mesh.extend(batch_size)
        fragments = rasterizer(sphere_meshes)
        for i in range(batch_size):
            image = fragments.pix_to_face[i, ..., 0].squeeze().cpu()
            image[image >= 0] = 1.0
            image[image < 0] = 0.0
            self.assertTrue(torch.allclose(image, image_ref))

        ####################################################
        #  3. Test that passing kwargs to rasterizer works.
        ####################################################

        #  Change the view transform to zoom in.
        R, T = look_at_view_transform(2.0, 0, 0, device=device)
        fragments = rasterizer(sphere_mesh, R=R, T=T)
        image = fragments.pix_to_face[0, ..., 0].squeeze().cpu()
        image[image >= 0] = 1.0
        image[image < 0] = 0.0

        ref_filename = "test_rasterized_sphere_zoom.png"
        image_ref_filename = DATA_DIR / ref_filename
        image_ref = convert_image_to_binary_mask(image_ref_filename)

        if DEBUG:
            Image.fromarray((image.numpy() * 255).astype(np.uint8)).save(
                DATA_DIR / "DEBUG_test_rasterized_sphere_zoom.png"
            )
        self.assertTrue(torch.allclose(image, image_ref))

        #################################
        #  4. Test init without cameras.
        ##################################

        # Create a new empty rasterizer:
        rasterizer = MeshRasterizer()

        # Check that omitting the cameras in both initialization
        # and the forward pass throws an error:
        with self.assertRaisesRegex(ValueError, "Cameras must be specified"):
            rasterizer(sphere_mesh)

        # Now pass in the cameras as a kwarg
        fragments = rasterizer(
            sphere_mesh, cameras=cameras, raster_settings=raster_settings
        )
        image = fragments.pix_to_face[0, ..., 0].squeeze().cpu()
        # Convert pix_to_face to a binary mask
        image[image >= 0] = 1.0
        image[image < 0] = 0.0

        if DEBUG:
            Image.fromarray((image.numpy() * 255).astype(np.uint8)).save(
                DATA_DIR / "DEBUG_test_rasterized_sphere.png"
            )

        self.assertTrue(torch.allclose(image, image_ref))


class TestPointRasterizer(unittest.TestCase):
    def test_simple_sphere(self):
        device = torch.device("cuda:0")

        # Load reference image
        ref_filename = "test_simple_pointcloud_sphere.png"
        image_ref_filename = DATA_DIR / ref_filename

        # Rescale image_ref to the 0 - 1 range and convert to a binary mask.
        image_ref = convert_image_to_binary_mask(image_ref_filename).to(torch.int32)

        sphere_mesh = ico_sphere(1, device)
        verts_padded = sphere_mesh.verts_padded()
        verts_padded[..., 1] += 0.2
        verts_padded[..., 0] += 0.2
        pointclouds = Pointclouds(points=verts_padded)
        R, T = look_at_view_transform(2.7, 0.0, 0.0)
        cameras = FoVPerspectiveCameras(device=device, R=R, T=T)
        raster_settings = PointsRasterizationSettings(
            image_size=256, radius=5e-2, points_per_pixel=1
        )

        #################################
        #  1. Test init without cameras.
        ##################################

        # Initialize without passing in the cameras
        rasterizer = PointsRasterizer()

        # Check that omitting the cameras in both initialization
        # and the forward pass throws an error:
        with self.assertRaisesRegex(ValueError, "Cameras must be specified"):
            rasterizer(pointclouds)

        ##########################################
        # 2. Test rasterizing a single pointcloud
        ##########################################

        fragments = rasterizer(
            pointclouds, cameras=cameras, raster_settings=raster_settings
        )

        # Convert idx to a binary mask
        image = fragments.idx[0, ..., 0].squeeze().cpu()
        image[image >= 0] = 1.0
        image[image < 0] = 0.0

        if DEBUG:
            Image.fromarray((image.numpy() * 255).astype(np.uint8)).save(
                DATA_DIR / "DEBUG_test_rasterized_sphere_points.png"
            )

        self.assertTrue(torch.allclose(image, image_ref[..., 0]))

        ########################################
        #  3. Test with a batch of pointclouds
        ########################################

        batch_size = 10
        pointclouds = pointclouds.extend(batch_size)
        fragments = rasterizer(
            pointclouds, cameras=cameras, raster_settings=raster_settings
        )
        for i in range(batch_size):
            image = fragments.idx[i, ..., 0].squeeze().cpu()
            image[image >= 0] = 1.0
            image[image < 0] = 0.0
            self.assertTrue(torch.allclose(image, image_ref[..., 0]))
