src/utils.py

import numpy as np
import trimesh
import tempfile
import torch
from scipy.spatial import Delaunay
from sklearn.cluster import KMeans
from .build_pipe import *
import spaces

pipe = build_pipe()

@spaces.GPU
def generate_terrain(prompt, num_inference_steps, guidance_scale, seed, random_seed, prefix, crop_size=None):
    """Generates terrain data (RGB and elevation) from a text prompt."""
    if prefix and not prefix.endswith(' '):
        prefix += ' '  # Ensure prefix ends with a space

    full_prompt = prefix + prompt
    if random_seed:
        generator = torch.Generator("cuda")
    else:
        generator = torch.Generator("cuda").manual_seed(seed)
        
    image, dem = pipe(full_prompt, num_inference_steps=num_inference_steps, guidance_scale=guidance_scale, generator=generator)

    if crop_size is not None:
        # Center crop the image and dem
        h, w, c = image[0].shape
        start_h = (h - crop_size) // 2
        start_w = (w - crop_size) // 2
        end_h = start_h + crop_size
        end_w = start_w + crop_size
    
        cropped_image = image[0][start_h:end_h, start_w:end_w, :]
        cropped_dem = dem[0][start_h:end_h, start_w:end_w, :]
    else:
        cropped_image = image[0]
        cropped_dem = dem[0]

    return (255 * cropped_image).astype(np.uint8), cropped_dem.mean(-1)

def create_3d_mesh(rgb, elevation, n_clusters=1000):
    """Creates a 3D mesh from RGB and elevation data.
    If n_clusters is 0, generates the full mesh.
    Otherwise, generates a simplified mesh using KMeans clustering with distinct colors.
    """
    rows, cols = elevation.shape
    x, y = np.meshgrid(np.arange(cols), np.arange(rows))
    points_2d = np.stack([x.flatten(), y.flatten()], axis=-1)
    elevation_flat = elevation.flatten()
    points_3d = np.column_stack([points_2d, elevation_flat])
    original_colors = rgb.reshape(-1, 3)

    if n_clusters <= 0:
        # Generate full mesh without clustering
        vertices = points_3d
        
        try:
            tri = Delaunay(points_2d)
            faces = tri.simplices
            mesh = trimesh.Trimesh(vertices=vertices, faces=faces, vertex_colors=original_colors)
            return mesh
        except Exception as e:
            print(f"Error during Delaunay triangulation (full mesh): {e}")
            return None
    else:
        n_clusters = min(n_clusters, len(elevation_flat))
        # Apply KMeans clustering for simplification
        kmeans = KMeans(n_clusters=n_clusters, random_state=0, n_init='auto')
        kmeans.fit(points_3d)
        cluster_centers = kmeans.cluster_centers_
        cluster_labels = kmeans.labels_

        # Use the cluster centers as the simplified vertices
        simplified_vertices = cluster_centers

        # Perform Delaunay triangulation on the X and Y coordinates of the cluster centers
        simplified_points_2d = simplified_vertices[:, :2]
        try:
            tri = Delaunay(simplified_points_2d)
            faces = tri.simplices
            # Ensure the number of vertices in faces does not exceed the number of simplified vertices
            valid_faces = faces[np.all(faces < len(simplified_vertices), axis=1)]
        except Exception as e:
            print(f"Error during Delaunay triangulation (clustered mesh): {e}")
            return None

        # Assign a distinct color to each cluster
        unique_labels = np.unique(cluster_labels)
        cluster_colors = {}
        for label in unique_labels:
            cluster_indices = np.where(cluster_labels == label)[0]
            if len(cluster_indices) > 0:
                avg_color = np.mean(original_colors[cluster_indices], axis=0).astype(np.uint8)
                cluster_colors[label] = avg_color
            else:
                cluster_colors[label] = np.array([255, 0, 0], dtype=np.uint8) # Red

        vertex_colors = np.array([cluster_colors[i] for i in range(n_clusters)])

        # Create the trimesh object
        mesh = trimesh.Trimesh(vertices=simplified_vertices, faces=valid_faces, vertex_colors=vertex_colors)
        return mesh

def create_3d_point_cloud(rgb, elevation):
    height, width = elevation.shape
    x, y = np.meshgrid(np.arange(width), np.arange(height))
    points = np.stack([x.flatten(), y.flatten(), elevation.flatten()], axis=-1)
    colors = rgb.reshape(-1, 3)

    return trimesh.PointCloud(vertices=points, colors=colors)

def generate_3d_view_output(prompt, num_inference_steps, guidance_scale, seed, random_seed, crop_size, vertex_count, prefix):
    rgb, elevation = generate_terrain(prompt, num_inference_steps, guidance_scale, seed, random_seed, prefix, crop_size)
    
    mesh = create_3d_mesh(rgb, 500*elevation, n_clusters=vertex_count)
    with tempfile.NamedTemporaryFile(suffix=".obj", delete=False) as temp_file:
        mesh.export(temp_file.name)
        file_path = temp_file.name
    # pc = create_3d_point_cloud(rgb, 500*elevation)
    # with tempfile.NamedTemporaryFile(suffix=".ply", delete=False) as temp_file:
    #     pc.export(temp_file.name, file_type="ply")
    #     file_path = temp_file.name

    return rgb, elevation, file_path

def generate_2d_view_output(prompt, num_inference_steps, guidance_scale, seed, random_seed, prefix):
    rgb, elevation = generate_terrain(prompt, num_inference_steps, guidance_scale, seed, random_seed, prefix)

    return rgb, elevation