Monte Carlo Path Tracer

A realistic Monte Carlo Path Tracer project for CS230 (Virtual Reality and Interactive 3D Graphics Display).

Features

• Supported effects:
  • color bleeding
  • transparent object
  • reflective object
  • soft shadow
  • caustic
• Global illumination with Monte Carlo Path Tracing
• Multi-thread rendering
• Basic .obj model rendering
• Anti-aliasing (by rendering subpixel)
• Simple texture mapping on planes
• Simple bounding box speeding up

System and Software Requirements

• Ubuntu v14.04+
• CMake v3.2.2+
• libpng

Project Structure

models/ 		# 3D models in .obj files for rendering
results/ 		# rendering results
vendor/ 		# third-party library (cameron314/concurrentqueue for multi-thread rendering)
src/			# source code
	/object		# dealing with 3D objects, material, etc.
	/utility 	# basic utility objects / functions / constants, including ray class, vector class and some global constants
 	Engine.cpp	# core rendering engine
 	Engine.h	# header file for core rendering engine
 	scene.cpp	# 3D scene builder
 	scene.h		# header file for 3D scene builder
 	main.cpp	# entrance 	

Usages

Build

mkdir bin && cd bin
cmake .. && make

Run

cd bin
./RayTracing	[-MCPT <true|false|mix>] 
			[-test_case <twist_mesh|teapot_mesh|mix_twist_mesh|load_obj>] 
			[-size <height> <width>] 
			[-view <position of viewpoint> <position of target>]
			[-obj 	 <path of .obj file>]
			[-meshtype <diff> <ks> <refl>]
			[-sample_num <number of sample per subpixel (default 1024)>]

• To render with MCPT, please toggle -MCPT true.

• The frame is set to be 5 units in front of the view point and not tilted.

• The default size of the rendered image is 640x480, and if specified in cli options, height / width should be 3 / 4.

• To render a .obj 3D model, please run with

    -test_case load_obj -obj <path of .obj file>
  

Demos

1. Box with balls

   • Global Illumination with Monte Carlo Path Tracing

   • with color bleeding, transparent object, reflective object, soft shadow and caustic effects

   • all diffuse surfaces are Lambertian surfaces

   • size 1280x960, 4x4 subpixel, 512 sample per subpixel

   • render with Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz (20 cores) in 5731.2s

     

   • run with

       ./RayTracing -MCPT true -view 0 0 -5 0 0 0
     

2. Box with a twist, a ball and texture

   • Global Illumination with Monte Carlo Path Tracing

   • with color bleeding, transparent object, soft shadow and caustic effects

   • .obj 3D model (the twist)

   • all diffuse surfaces are Lambertian surfaces

   • texture mapping (ground and the back wall)

   • render with Intel Xeon E5-2666 v3 (Haswell) (36 cores) on AWS EC2 c4.8xlarge in 1206.01s

     

   • run with

       ./RayTracing -MCPT true -test_case mix_twist_mesh -view 2 4 -12 2 4 0
     

3. Box with a reflective teapot and texture

   • Global Illumination with Monte Carlo Path Tracing

   • with color bleeding, soft shadow, reflective object effects

   • .obj 3D model (the teapot) (more meshes), with phong shading

   • all diffuse surfaces are Lambertian surfaces

   • texture mapping (the ground and the back wall)

   • size 1280x960, 2x2 subpixel, 1024 sample per subpixel

   • render with Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz (56 cores) in 13788.39s

     

   • run with

       ./RayTracing -MCPT true -test_case load_obj -obj ../models/teapot2.obj -meshtype 0.0 0.0 1.0
     

Further Possible Improvements

• MCPT with direct ray casting
• KD-tree speedup
• texture mapping on .obj 3D models

Reference

• https://www.scratchapixel.com/
• http://www.flipcode.com/archives/Raytracing_Topics_Techniques-Part_1_Introduction.shtml
• Shirley, P., & Morley, R. K. (2008). Realistic ray tracing. AK Peters, Ltd..
• wiki: path tracing
• The ground texture is borrowed from ppwwyyxx/Ray-Tracing-Engine