GoTracer

A Go implementation of Ray Tracing in One Weekend by Peter Shirley.

Features:

• Provides a library and executable to trace a bunch of spheres with Matte, Metal and transparent surfaces.
• Provides a framework to ray trace a bunch or spheres on a distributed systems controlled by master/agent configuration

Usages

Prepare rendering spec as per Tracing Specification

Basic

go get github.com/DheerendraRathor/GoTracer

goTracer --spec=/path/to/spec.json

On distributed Systems

1. Install and run ray tracing agent on all machines

go get github.com/DheerendraRathor/GoTracer/net/agent

# Provide an addr where agent will listen. Address (including port) must be visible to master
agent --addr=0.0.0.0:1233

2. Prepare agents.json file with list of all agents

[
  "localhost:9190",
  "localhost:9191",
  "localhost:9192"
]

3. Install and run master

go get github.com/DheerendraRathor/GoTracer/net/master

master --spec=/path/to/spec.json --agents=/path/to/agents.json

4. Sit back and relax while image is being rendered :)

As library

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"

	"github.com/DheerendraRathor/GoTracer/models"
	"github.com/DheerendraRathor/GoTracer/tracer"
)

func main() {

	file, e := ioutil.ReadFile("mySpecFile.json")
	if e != nil {
		panic(fmt.Sprintf("File error: %v\n", e))
	}

	var env models.World
	json.Unmarshal(file, &env)

	/*
		This channel is used to track progress of ray tracing. If env.Settings.ShowProgress is set to true.
		On each pixel traced a `false` value is pushed to progress channel. And once all pixel are processed a `true` value is pushed into channel.

		It is responsibility of caller to create sufficiently large buffered channel and read it responsibly if env.Settings.ShowProgress is true.
		Otherwise program might hang.
	*/
	progress := make(chan *models.Pixel, 100)
	closeChan := make(chan bool)
	defer close(progress)

	go goTracer.GoTrace(&env, progress, closeChan)

	go func() {
		for pixel := range progress {
			if pixel == nil {
				// Rendering complete
				return
			}
			// Do processing with pixel here.
			// Want to generate JPEG? GIF? Real time rendering on UI? Show weird looking progress bar? Your call. You've the pixels now
		}
	}()

	// To stop rendering in middle, just pass a value to closeChan.
	// GoTracer does a non-blocking check on closeChan before rendering a pixel. If channel has a value, it will stop rendering and send nil to
	// progress channel.
	// Caveat: Existing goroutines for other pixel will continue to run.

}

Tracing Specification

This program takes a JSON specification of environment to be traced. Currently only spheres are supported.

{
  "Settings": {
    "ShowProgress": true,
    "RenderRoutines": -1,
    "RenderDepth": 10
  },
  "Image": {
    "OutputFile": "./out/renderedImage.png",
    "Width": 400,
    "Height": 200,
    "Samples": 10,
    "Patch": [0, 200, 0, 400]
  },
  "Camera": {
    "LookFrom": [-2, 1, 0.5],
    "LookAt": [0, 0, -1],
    "UpVector": [0, 1, 0],
    "FieldOfView": 45,
    "AspectRatio": 2,
    "Focus": 2.69,
    "Aperture": 0.04
  },
  "Objects": {
    "Spheres": [
      {
        "Center": [0, 0, -1],
        "Radius": 0.5,
        "Surface": {
          "Type": "Lambertian",
          "Albedo": [0.8, 0.1, 0.1],
          "Fuzz": 0.1,
          "RefIndex": 1.3
        }
      }
    ]
  }
}

Note: list[x][n] => list of elements of type x with size n