TRM

TRM (Tiny Ray Marcher) is a C++ project that implement a very small ray marching algorithm. The project implements the fundamental components of a path tracer, and even provides an easy to use scene definition file.

Efficiency

By changing specific key configuration values in a rendered image, it is possible to significantly alter the quality of the image, in direct relation to the runtime of the program. However some settings will produce a better output image, for less cost to runtime. The main two settings that we consider here, is the spp and the resolution. By doubling the spp it can be considered that we are rendering twice as many images, and combining the images after the fact. While doubling the resolution is equivalent to rendering four times the number of images, and connecting the images as the four quadrants of the output image.

After collecting the data it is clear that doubling the resolution in both axis is indeed about equivalent to four times the samples per pixel. However, increasing the resolution produces a visually shaper images, even with very few samples.

Configuration

The scene file is based upon JSON file format. The general file is formatted like so:

{
  "spp": 128,
  "maxiumumDepth": 64,
  "resolution": [2000, 2000],
  "camera": {
    "fov": 1.5707,
    "center": [0.0, 0.0, 0.0],
    "up": [0.0, 1.0, 0.0],
    "pos": [0.0, 0.0, -6.0]
  },
  "materials": {
    ...
  },
  "objects": {
    ...
  }
}

General

These are general settings for the render, they control how the renderer will function, and the quality of the produced image. Changing these values will significantly impact the runtime of the renderer. The amount that each value effects the runtime is described in the section on Efficiency.

Materials