raytracer

A ray tracer that supports various primitives, area lighting, and certain dielectrics.

Features

• Supports many primitives: Boxes (with rotation, scaling, translation), triangles, planes, spheres
• Parallelogram area lights with a variable number of samples along each axis.
• Soft shadowing is implemented using a stratified, stochastic approach (i.e., stratified Monte Carlo method); a grid is formed over the parallelogram using the number of samples given for each axis, and a random sample is then taken for each cell. Objects' diffuse/specular are still computed as if the area light were a point light, however. (This is more of a problem for specular highlights.)
• Refraction / dielectric media. By specifying an object with a refractive index != 0, the object is then considered to be a dense dielectric, and as such it transmits light (with its inside media having the refractive index given). Beer's law (to account for absorption) hasn't been implemented yet.
• Antialiasing via supersampling using a simple grid-based approach. The number of samples per row and column is defined in the scene file.
• OpenMP to parallelize rows of rays. Using a tile-based approach may works better (due to memory locality), but without an acceleration structure it probably isn't a huge concern.

Scene files

The following is a specification of the scene input files. See scenes/ for examples. The first block are the initial features that I implemented; by writing ENABLEEXTRAFEATURES on a line, the second block of features opens for use. float01 means a float that ranges from 0 to 1; similarly, vector01 means a vector with components ranging from 0 to 1.

NEAR <float: near plane>
LEFT <float: left plane>
RIGHT <float: right plane>
BOTTOM <float: bottom plane>
TOP <float: top plane>
RES <int: x resolution> <int: y resolution>
SPHERE <string: name> <vector: position> <vector: scale> <vector01: RGB color> <float01: ambient coefficient> <float01: diffuse coefficient> <float01: specular coefficient> <float01: reflectivity (if not dielectric)> <float: specular exponent>
LIGHT <string: name> <vector: position> <vector01: RGB color>

ENABLEEXTRAFEATURES
AASAMPLES <integer: number of samples per pixel is AASAMPLES^2>
MAXDEPTH <integer above 0: maximum recursion depth>
REFRACTIVEINDEX <float: ambient refractive index>
BIAS <float: bias (or epsilon) value used in ray tracing>
BOX <string: name> <vector: position> <vector: scale> <vector: rotation, in degrees, along X, Y, Z> < ... material properties ... > <float: refractive index>
SPHERE <... normal parameters ...> <refractive index>
PLANE <string: name> <vector: normal> <float: distance> <... material properties (same as sphere, box, etc.) ... >
TRIANGLE <name> <vector: vertex 1> <vector: vertex 2> <vector: vertex 3> <... material properties ...>
AREALIGHT <string: name> <vector: position (center)> <vector: axis1> <vector: axis2> <float: axis1 length> <float: axis2 length> <int above 0: axis1 samples> <int above 0: axis2 samples> <vector01: RGB color>