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Core features

Python interface

Inverse rendering

Plugin references

  1. Docs
  2. Rendering a scene

Rendering a scene

PSDR-CUDA renders virtual scenes described using a simplified version of Mitsuba’s XML description language.

Loading a scene

PSDR-CUDA provides two functions for loading scenes in Python:

  • psdr_cuda.Scene.load_file(): load the scene from an XML file on disk;

  • psdr_cuda.Scene.load_string(): load the scene from a string in memory.

Here is a complete Python example on how to load a PSDR-CUDA scene from an XML file:

import psdr_cuda

scene = psdr_cuda.Scene()
scene.load_file('scene.xml')

Forward rendering of a scene

Once a scene has been loaded, it can be rendered as follows:

# Initialize an integrator
integrator = psdr_cuda.DirectIntegrator()

# Start rendering!
sensor_id = 0
image = integrator.renderC(scene, sensor_id)

The sensor_id variable is an integer specifying which sensor to use (as PSDR-CUDA allows a scene to contain multiple sensors with identical resolutions).

The image variable returned by the integrator’s renderC() function is a RGB image stored as an Enoki CUDA array of the type enoki.cuda.Vector3f. This variable can be converted to a Numpy array and saved as an OpenEXR image named image.exr using OpenCV:

# Cast to a Numpy array and reshape
out = image.numpy().reshape((scene.opts.height, scene.opts.width, 3))

# Save to OpenEXR image using OpenCV
import cv2
out = cv2.cvtColor(out, cv2.COLOR_RGB2BGR) # OpenCV uses BGR
cv2.imwrite("image.exr", out)

In the code above, scene.opts is an instance of psdr_cuda.RenderOption whose C++ definition is

struct RenderOption {
    int width, height;  // Image resolution
    int spp;            // Spp for the main image/interior integral
    int sppe;           // Spp for primary edge integral
    int sppse;          // Spp for secondary edge integral
    int log_level;
};

This variable is automatically set when loading the scene but can also be overwritten as follows.

# Delay the configuration of the scene
scene.load_file('scene.xml', auto_configure=False)

# Overwriting the render options
scene.opts.width     = 256
scene.opts.height    = 256
scene.opts.spp       = 32

# Configure the scene
scene.configure()

Note that a scene must be configured before being rendered. If the scene is loaded with auto_configure=False without being manually configured via scene.configure(), attempting to render it will cause an assertion failure.

Introduction
Introduction