A simple ray tracer made in a weekend.
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A plain C implementation of the Weekend Raytracer challenge. I just followed the instructions laid out on the online book:
Title (series): โRay Tracing in One Weekend Seriesโ
Title (book): โRay Tracing in One Weekendโ
Author: Peter Shirley
Editors: Steve Hollasch, Trevor David Black
Version/Edition: v3.2.3
Date: 2020-12-07
URL (series): https://github.com/RayTracing/raytracing.github.io
URL (book): https://raytracing.github.io/books/RayTracingInOneWeekend.htmlAll you need is a shell and a C compiler like gcc or clang.
Just clone the repo and run make:
$ git clone https://github.com/librity/weekendrt.git
$ cd weekendrt
$ make exampleA beautiful image should pop out of your terminal like magic.
Rainbow gradient:
Tame Impala's next album cover:
3000+ objects:
Anti-aliasing, 100 samples per pixel:
Dynamic camera:
Defocus blur (a.k.a. Depth of field):
Multiple materials:
ft_libbmp implementation based on:
- https://engineering.purdue.edu/ece264/17au/hw/HW15
- https://github.com/marc-q/libbmp
- https://medium.com/sysf/bits-to-bitmaps-a-simple-walkthrough-of-bmp-image-format-765dc6857393
The best way to write the header is to define a struct,
set all the values and dump it straight to the file.
typedef struct { // Total: 54 bytes
uint16_t type; // Magic identifier: 0x4d42
uint32_t size; // File size in bytes
uint16_t reserved1; // Not used
uint16_t reserved2; // Not used
uint32_t offset; // Offset to image data in bytes from beginning of file (54 bytes)
uint32_t dib_header_size; // DIB Header size in bytes (40 bytes)
int32_t width_px; // Width of the image
int32_t height_px; // Height of image
uint16_t num_planes; // Number of color planes
uint16_t bits_per_pixel; // Bits per pixel
uint32_t compression; // Compression type
uint32_t image_size_bytes; // Image size in bytes
int32_t x_resolution_ppm; // Pixels per meter
int32_t y_resolution_ppm; // Pixels per meter
uint32_t num_colors; // Number of colors
uint32_t important_colors; // Important colors
} BMPHeader;The only values we need to worry about are width_px, height_px
and size, which we calculate on the fly;
the rest represent configurations
and we can treat them as constants for most purposes.
We then write the actual contents of the file line-by line,
with some padding information.
My bitmap implementation is very lousy and doesn't handle compression.
This makes for 1080p files that are over 5 mb big.
I transformed all the pictures in the gallery to .png
so this README would load faster,
but they were all originally generated as .bmp with ft_libbmp.
- Bold variables are Euclidean Vectors, like
PandC. - Normal variables are scalars, like
tandr.
Given a origin A, and a direction b,
the linear interpolation of a line with a free variable t
generates a ray P(t):
The scalar t represents the translation of the ray,
or how much it need to advance to reach an arbitrary point in its path.
An arbitrary point P is on the surface of a sphere
centered in C with radius r
if and only if it satisfies the equation:
An arbitrary ray P(t) of origin A and direction b
intersects a sphere centered in C if and only if
t is a root of:
The quadratic above combines equations (I) and (II),
and we can solve for t with the quadratic formula:
The reflection r of an incident ray v
on an arbitrary point with a normal n
can be calculated with:
Given an angle of ฮธ of an incident ray R,
and the refractive indices of the two surfaces ฮท and ฮท',
we calculate the angle ฮธ' of the refracted ray R' with:
The refracted ray R' has a perpendicular component Rโฒโฅ
and a parallel component Rโฒโฅ,
which we can calculate with:
Norminette Github Action by @AdrianWR
- https://github.com/marc-q/libbmp
- https://github.com/MetalheadKen/RayTracingInOneWeekend
- https://github.com/carld/ray-tracer
- https://github.com/AngusLang/rayt
- https://en.wikipedia.org/wiki/Dot_product
- https://en.wikipedia.org/wiki/Quadratic_formula
- https://en.wikipedia.org/wiki/Snell's_law
- https://en.wikipedia.org/wiki/Refractive_index
- https://en.wikipedia.org/wiki/Specular_reflection#Direction_of_reflection
- https://en.wikipedia.org/wiki/Dielectric
- https://en.wikipedia.org/wiki/Fresnel_equations
- https://en.wikipedia.org/wiki/Schlick%27s_approximation
- https://en.wikipedia.org/wiki/Thin_lens
- https://graphicscompendium.com/raytracing/11-fresnel-beer
- https://gaim.umbc.edu/2010/09/07/approximation/
- https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law
- https://stats.stackexchange.com/questions/137907/division-of-vectors
- http://www.r-tutor.com/r-introduction/vector/vector-arithmetics
- https://physics.stackexchange.com/questions/111652/can-we-divide-two-vectors
- https://mathworld.wolfram.com/VectorDivision.html
- https://en.wikipedia.org/wiki/List_of_Unicode_characters
- https://en.wikipedia.org/wiki/Extended_ASCII
- https://en.cppreference.com/w/cpp/io/manip/flush
- https://www.cplusplus.com/reference/cstdio/printf/
- https://linux.die.net/man/3/random
- https://cplusplus.com/reference/cmath/fmin/
- https://overiq.com/c-programming-101/fwrite-function-in-c/
- https://www.c-programming-simple-steps.com/typedef-in-c.html
- https://www.geeksforgeeks.org/use-fflushstdin-c/
- https://www.geeksforgeeks.org/how-to-measure-time-taken-by-a-program-in-c/
- https://www.tutorialspoint.com/c_standard_library/c_function_fwrite.htm
- https://www.tutorialspoint.com/c_standard_library/c_function_perror.htm
- https://stackoverflow.com/questions/4264127/correct-format-specifier-for-double-in-printf
- https://stackoverflow.com/questions/13252697/writing-bits-to-a-file-in-c
- https://stackoverflow.com/questions/39002052/how-i-can-print-to-stderr-in-c
- https://stackoverflow.com/questions/5248919/undefined-reference-to-sqrt-or-other-mathematical-functions
- https://stackoverflow.com/questions/4842424/list-of-ansi-color-escape-sequences
- https://stackoverflow.com/questions/5834635/how-do-i-get-double-max
- https://stackoverflow.com/questions/33058848/generate-a-random-double-between-1-and-1
- https://stackoverflow.com/questions/9912151/math-constant-pi-value-in-c#9912169
- https://askubuntu.com/questions/749882/how-to-recursively-and-automatically-convert-all-bmp-images-to-png-files-in-a-gi
- https://www.codeproject.com/tips/800474/function-pointer-in-c-struct
- https://aticleworld.com/function-pointer-in-c-struct/
- https://casual-effects.com/markdeep/
- https://github.github.com/gfm/
- https://emojipedia.org/sun/
- https://jaantollander.com/post/scientific-writing-with-markdown/
- https://paperhive.org/help/markdown
- http://www.sciweavers.org/free-online-latex-equation-editor
- http://latex.codecogs.com/
- http://csrgxtu.github.io/2015/03/20/Writing-Mathematic-Fomulars-in-Markdown/
- https://en.wikibooks.org/wiki/LaTeX/Mathematics#Controlling_horizontal_spacing