nullsense/tracey

A 3d ray tracer in C++ (High School Project)

Tracey

3d Ray Tracer written in C++ (multithreaded)

Final images

5.8 min, 1080p, glass smoothed bunny

.obj file model rendering

Smoothed stanford bunny (4968 triangles)	Not smoothed stanford bunny (4968 triangles)
4.4 min, 1080p, 1x SS	4.4 min, 4k, 1x SS

Smoothed elephant (1143 triangles)	Not smoothed elephant (1143 triangles)
1min, 1080p, 1x SS	1min, 1080p, 1x SS

Features:

• Multithreading
• Triangle meshes (.obj)
• Vertex normal interpolation (meshes)
• Supersampling anti-aliasing
• Blinn-Phong shading (ambient, diffuse and specular terms)
• Hard shadows
• Point lights
• Depth checking
• Reflections
• Refractions

TODO

• Multithread in chunks
• Bezier curves
• Soft shadows
• Area Lights
• Glossy reflections
• Beer's law
• Texture mapping
• Png output (png++)
• Transparent shadows
• Motion blur
• Depth of field
• Speedup structures (kd-trees, etc.)

Geometric primitives:

• Planes
• Spheres
• Triangles
• Disks (WIP)
• Boxes (WIP)

Ray tracing introduction (with screenshots)

Ray tracing is a 3d rendering technique that attemps to generate photorealistic images by tracing rays that are shot from every pixel of the image and applying mathematical and physical concepts to accomplish techniques described below.

Ambient Light

The light that gets scattered all around the scene, takes object ambient reflection parameter into consideration.

Diffuse lighting

Diffuse shading applies a shadow on an object by getting the cosine angle of the closest object's normal and light direction, giving the object a matte effect. The lower the angle of the light direction to the object's normal, the brighter that point of the object.

Shadows

To check if a particular point of the image is a part of a shadow, a ray is traced from an intersection point to the light source. If the intersection point to light position ray hits some object along the way, the intersection point is a shadow.

Specular lighting / Blinn-Phong illumination

Specular reflection can be observed when a light is being shone on an object with shinyness value. The result of that is a specular highlight on the surface of the object. The light source's position and the viewing angle contributes to the specular highlight's position. The light source's intensity and color define it's size and color

Reflections

Reflections are implemented by casting rays from the light source to an object and then by casting a reflection ray from intersection point of the object, directed along the reflection vector. This method is used recursively to add realism by allowing for multiple reflections in the scene.

Refractions (glass bunny)

tracey's Issues

Shadows are lighter at the base/starting point of the shadow

This effect can be easily seen when the shadow gets cast on the maroon sphere and also the shadow that the maroon sphere casts itself.

Boxes and Disks not getting diffuse shaded

Seen here:

http://i.imgur.com/W2a5L9d.png

Shadows get displaced in a bad manner when casted on another sphere

Illustrated here:

And here:

Box shadows getting cast 2 ways

http://i.imgur.com/hOncxwI.png

Reflection and refraction don't work in unison, only apart