Draw 3D Lines and Point

We usually draw points and lines in the 3D world to debug when developing new features and fixing bugs. There are two types of visualization tools can be used: line and point. In this section, we will show how to use these tools. First of all, let’s make an environment and define the tool function which returns a set of points representing a straight line and the color for each point. The points gradually become pink with the distance increasing.

from metaurban.envs import SidewalkStaticMetaUrbanEnv
import numpy as np
import os
render = not os.getenv('TEST_DOC')

# Define a tool function. 
def make_line(x_offset, y_offset, height, y_dir=1, color=(1,105/255,180/255)):
    points = [(x_offset+x,x*y_dir+y_offset,height*x/10+height) for x in range(10)]
    colors = [np.clip(np.array([*color,1])*(i+1)/11, 0., 1.0) for i in range(10)]
    if y_dir<0:
        points = points[::-1]
        colors = colors[::-1]
    return points, colors

# create environment
env = SidewalkStaticMetaUrbanEnv(dict(use_render=render, object_density=0.1)) 

[INFO] Environment: SidewalkStaticMetaUrbanEnv
[INFO] MetaUrban version: 0.0.1
[INFO] Sensors: [lidar: Lidar(), side_detector: SideDetector(), lane_line_detector: LaneLineDetector(), main_camera: MainCamera(1200, 900), dashboard: DashBoard()]
[INFO] Render Mode: onscreen
[INFO] Horizon (Max steps per agent): None

Lines

The API we are using takes a list of lines as input. A line is represented by a list of points. Thus we create two lines in the following script and draw them in the scene. Also, colors can be specified for each point.

env.reset() # launch the simulation
line_1, color_1 = make_line(env.agent.position[0], env.agent.position[1], 0.5, 1) # define line 1 for test
line_2, color_2 = make_line(env.agent.position[0], env.agent.position[1], 0.5, -1) # define line 2 for test
lines = [line_1, line_2]
colors = [color_1, color_2]

try:
    drawer = env.engine.make_line_drawer(thickness=5) # create a line drawer
    drawer.draw_lines(lines, colors) # draw lines
    
    for i in range(100):
        env.step([0,0])
finally:    
    env.close()

[INFO] Assets version: 0.0.1
[INFO] Known Pipes: glxGraphicsPipe
[INFO] Start Scenario Index: 0, Num Scenarios : 1
[WARNING] Not set var:walk_on_all_regions, so that agents can walk on all regions (orca_navigation.py:561)
[INFO] Agents can walk on all regions
[INFO] Agents can walk on all regions

Points

MetaUrban also provides point drawer to visualize a set of points. The usage of this function is almost the same as the line drawer. The following example creates a point drawer and update the point positions every frame.

env.reset() # launch the simulation
try:
    drawer = env.engine.make_point_drawer(scale=1) # create a point drawer
    for i in range(100):
        
        # draw different lines every step
        line_1, color_1 = make_line(env.agent.position[0], env.agent.position[1], 0.5, 0.01*i) # define line 1 for test
        line_2, color_2 = make_line(env.agent.position[0], env.agent.position[1], 0.5, -0.01*i) # define line 2 for test
        points = line_1 + line_2 # create point list
        colors = color_1+ color_2
        drawer.reset()
        drawer.draw_points(points, colors) # draw points
        
        env.step([0,0])
finally:    
    env.close()

In addition, the points can work with lines. In the following example, a list of points are visualized with lines, while the other one is visualized with points. Besides, we cancel the reset to keep previous drawn points and lines.

env.reset() # launch the simulation
try:
    point_drawer = env.engine.make_point_drawer(scale=1) # create a point drawer
    line_drawer = env.engine.make_line_drawer(thickness=5) # create a line drawer
    for i in range(100):
        
        if i%5==0:
            # draw different lines every step
            line_1, color_1 = make_line(env.agent.position[0], env.agent.position[1], 0.5, 0.01*i) # define line 1 for test
            line_2, color_2 = make_line(env.agent.position[0], env.agent.position[1], 0.5, -0.01*i) # define line 2 for test
            points = line_1
            point_colors = color_1
            lines = [line_2]
            line_colors = [color_2]
            # drawer.reset()
            point_drawer.draw_points(points, point_colors) # draw lines
            line_drawer.draw_lines(lines, line_colors)
        
        env.step([0,0])
finally:    
    env.close()