Wavefront GPU Path Tracer

Wavefront GPU Path Tracer is a ray tracing renderer. Apart from the ray tracing rendering features, a GPU implementation is developed to accelarate the efficiency of tracing. The implementation is based on a cpu ray tracer I made. The implementation is based on the paper Megakernels considered harmful: wavefront path tracing on GPUs by Samuli Laine, Tero Karras, and Timo Aila. Depends on the features enabled, the GPU version can outperform the CPU version 3x - 10x. Apart from the orignal features implemented in the template, the following feature is further developed:

Graphics related

• CPU Path Tracing
• wavefront GPU Path Tracing
• BVH(acceleration structure)
  • BLAS/TLAS
• skybox
• multiple light sources
• reflection / refraction
• NEE (Next Event Estimation)
• anti-aliasing
• microfacet BRDF
• gamma correction

Engine related

• .obj model loading
• material (reflection, refraction, texture)
• texture loading & mapping
• scene file loading

IDE

Visual Studio 2022

Screenshots

How to run

Open tmpl_2022-rt.sln with Visual Studio. Select a project (either CPUPathTracer or GPUPathTracer). Build.

Inspect traversal

Toggle Inspect Traversal checkbox in the panel will turn into traversal debug mode.

How to configure

Scene

There are several scenes available in assets folder. In renderer.h, the user can set the path to the scene file and start the program. The scene will be loaded automatically. A scene template looks like the following

<?xml version="1.0" encoding="UTF-8"?>
<scene>
    <!-- Scene Information -->
    <scene_name>wok scene</scene_name>
	<plane_texture_location>../assets/textures/Stylized_Wood_basecolor.tga</plane_texture_location>
    <skydome_location>../assets/harties_4k.hdr</skydome_location>
	<!-- Light List -->
    <lights>
        <!-- Light 0 -->
        <light>
	    <position>
                <x>0</x>
                <y>4.5</y>
                <z>2.0</z>
            </position>
            <rotation>
                <x>0.0</x>
                <y>0.0</y>
                <z>0.0</z>
            </rotation>
		<size>1</size>
		<color>
		   <x>24</x>
                   <y>24</y>
                   <z>22</z>
                </color>
        </light>
		<light>
                <position>
                   <x>3.3</x>
                   <y>0</y>
                   <z>2</z>
               </position>
               <rotation>
                  <x>0.0</x>
                  <y>120.0</y>
                  <z>90.0</z>
              </rotation>
                  <size>1</size>
                  <color>
                        <x>48</x>
                        <y>48</y>
                        <z>44</z>
                  </color>
        </light>
        <!-- Add more lights as needed -->
    </lights>
    <!-- Object List -->
    <objects>
        <!-- Object 1 -->
        <object>
            <mesh_idx>0</mesh_idx>
            <material_idx>0</material_idx>
            <position>
                <x>0.0</x>
                <y>1</y>
                <z>2.8</z>
            </position>
            <rotation>
                <x>-90.0</x>
                <y>0.0</y>
                <z>180.0</z>
            </rotation>
        </object>
        <object>
			<mesh_idx>2</mesh_idx>
            <material_idx>1</material_idx>
            <position>
                <x>1.5</x>
                <y>2</y>
                <z>1</z>
            </position>
            <rotation>
                <x>0</x>
                <y>0.0</y>
                <z>0.0</z>
            </rotation>
        </object>
        <!-- Add more objects as needed -->
    </objects>
	<!-- Mesh List -->
    <meshes>
        <!-- Mesh 0 -->
        <mesh>
            <model_location>../assets/urna.obj</model_location>
			<scale>
                <x>0.005</x>
                <y>0.005</y>
                <z>0.005</z>
            </scale>
        </mesh>
		<mesh>
            <model_location>../assets/sphere.obj</model_location>
			<scale>
                <x>0.5</x>
                <y>0.5</y>
                <z>0.5</z>
            </scale>
        </mesh>
        <mesh>
            <model_location>../assets/cup.obj</model_location>
			<scale>
                <x>0.2</x>
                <y>0.2</y>
                <z>0.2</z>
            </scale>
        </mesh>
        <!-- Add more objects as needed -->
    </meshes>
	<materials>
		<!-- Material 0 -->
		<material>
			<reflectivity>0.0</reflectivity>
			<refractivity>0.0</refractivity>
			<absorption>
                <x>0.0</x>
                <y>0.0</y>
                <z>0.0</z>
            </absorption>
			<roughness>0.3</roughness>
			<texture_location>../assets/textures/urna.jpg</texture_location>
		</material>
		<material>
			<reflectivity>0.0</reflectivity>
			<refractivity>1.0</refractivity>
			<absorption>
                <x>0.3</x>
                <y>0.3</y>
                <z>0.3</z>
            </absorption>
		<texture_location>../assets/textures/white.png</texture_location>
		</material>
	</materials>
</scene>

Asset References

Sepcial thanks to these amazing free skyboxes and models online

Urn for the Piłsudski Mound

Torii - Japanese Gate

Wok

Painting by Stanisław Ignacy Witkiewicz

Hollow Knight

Game Table

Studio Room

Path At The Hill During Sunny Day

Milky Way Skybox HDRI panorama

Sky Pano - Milkyway

Wooden Stylised Carriage