CPURayTracer

       

About

A CPU ray tracer built entirely from scratch in C++.

Features

• Ambient, diffuse and specular shading
• Directional lights
• Attenuated point lights
• Depthcueing
• Hard shadows
• Soft shadows
• Reflection
• Transparency
• Refraction
• Depth of field
• Texture mapping
• BVH acceleration

Setup Instructions

Build the ray tracer using the given Makefile with

make

and run using

./raytracer scenefile [outputfile] [softshadows] [dof]

• scenefile - path to input file containing scene description
• outputfile - name for final output image file (optional)
• softshadows - soft shadow toggle, 0 = off, 1 = on (optional)
• dof - depth of field toggle, 0 = off, 1 = on (optional)

Note that it may take several seconds for the ray tracer to complete rendering the scene.

Example

To render the demo scene included in this repo, navigate to this directory in your terminal of choice and — if you have yet to do so — build the project with

make

and then run the ray tracer on the demo scene:

./raytracer scenes/demo-scene.txt

The output image will appear in a file named demo-scene.ppm located in the scenes folder.

Scene Description Files

Scenes are defined in simple text files which contain information about the camera, lighting, materials, and the geometry of objects in the scene. For an example of a scene description file, see demo-scene.txt.

The syntax for scene description files is defined as follows, where entries in bold are keywords and entries in italics are variables:

Camera

eye eye_x eye_y eye_z (camera position)

viewdir vdir_x vdir_y vdir_z (camera view direction)

updir up_x up_y up_z (camera up direction)

vfov vfov (vertical field of view, in degrees)

imsize width height (size of the output image in pixel units)

bkgcolor r g b (background color in terms of r, g, b components defined on a scale from 0-1)

viewdist d (depth of field focus distance)

Lighting

light x y z w r g b ((x, y, z, 1) = point light position, (x, y, z, 0) = directional light direction, with rgb light color)

attlight x y z w r g b c₁ c₂ c₃ (attenuated point light)

depthcueing dc_r dc_g dc_b a_max a_min dist_max dist_min (depthcueing)

Materials

mtlcolor Od_r Od_g Od_b Os_r Os_g Os_b ka kd ks n α η (material properties, treated as a state variable such that all subsequently-defined objects use the immediately-preceding material properties)

Textures

texture ppm (path to ppm texture file, treated as a state variable in the same way as materials)

Primitives

sphere cx cy cz r (sphere defined by its center point and radius)

Triangles

list of vertex positions

v x₁ y₁ z₁
v x₂ y₂ z₂
v x₃ y₃ z₃
v x₄ y₄ z₄
. . .

list of vertex normals

vn nx₁ ny₁ nz₁
vn nx₂ ny₂ nz₂
vn nx₃ ny₃ nz₃
vn nx₄ ny₄ nz₄
. . .

list of texture coordinates

vt u₁ v₁
vt u₂ v₂
vt u₃ v₃
vt u₄ v₄
. . .

list of triangle definitions, consisting of appropriate indices into the vertex arrays, starting at 1

f v₁/vt₁/vn₁ v₂/vt₂/vn₂ v₃/vt₃/vn₃
f v₁/vt₁/vn₁ v₂/vt₂/vn₂ v₄/vt₄/vn₄
. . .

Note that triangles are defined more-or-less according to the .obj file format, such that most .obj files should provide geometry combatible with this renderer.