1. Overview

Simple RayTracer with miniLibX

(rt_file/test_obj/multi_009.rt)

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2. How to use

2-1) Clone and compile

git clone https://github.com/42minirt/miniRT.git
cd miniRT
make

2-2) Execute

Some sample setting files in rt_file/

./miniRT <scene_setting_file.rt>

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3. How to set scene

• The drawing scene is described in a scene setting file; rt file
• Load rt file as a program argument

3-1) format

• filename : rt file
• extension : .rt
• format

  • id and parameters on as single line.

  • general

     < id >         < paramters >
     A:  Ambient    lightning_ratio[0,1]                                                                            RGB[0,255]
     C:  Camera     viewpoint(xyz)         orientation_vec(xyz)[-1,1]   FOV[0,180]
     L:  Light      point(xyz)                                          light_brightness_ratio[0,1]                 RGB[0,255]
     SL: Spotlight  Light_point(xyz)       orientation_vec(xyz)[-1,1]   light_brightness_ratio[0,1]   angle[0-90]   RGB[0,255]
    
     sp: Sphere     center_point(xyz)                                   diameter                                    RGB[0,255]   <options>
     pl: Plane      point(xyz)             orientation_vec(xyz)[-1,1]                                               RGB[0,255]   <options>
     cy: Cylinder   bottom_center(xyz)     orientation_vec(xyz)[-1,1]   diameter    height                          RGB[0,255]   <options>
     co: Corn       bottom_center(xyz)     orientation_vec(xyz)[-1,1]   diameter    height                          RGB[0,255]   <options>
    

  • option

    < option id >   < parameters >
    perfect_ref
    checker         RGB
    image           "image_texture_path" "bumpmap_path" 
    

  • example

    A   0.2                                          255, 255, 255
    
    C   -50, 0, 20      0, 0, 1     70
    
    L   -40,50,00                   0.6              10, 0, 255
    
    SL  -40,50,00       0, 0, 1     0.6     60.0     10, 0, 255
    
    sp  0,0,20                     12.6              10, 0, 255
    
    pl  0, 0, -10       0, 1, 0                      0, 0, 225
    
    cy  50, 0, 20       0, 0, 1     14.2    21.42    10, 0, 255  perfect_ref
    
    co  0, 0, 0         0, 0, 1     14.2    21.42    10, 0, 255  checker      0, 0, 0
    
    

3-2) coordinate

This program uses a Left-hand coordinate system

  +y
  |  +z
  | /
  |/_____ +x
 O

3-3) Description Rule

• Each parameter of an id must be written in the order that complies with the format
• Lines starting with # are considered comment lines
• If a rt file with an invalid format is loaded, the program will terminate

i) string, id

• id (A, C, L, SL, sp, pl, cy), option specifier (perfect_ref, checker, image) are determined by an exact match
• The number of A, C must each be 1

ii) numeric value

• normalized_vec allows xyz[-1,1], but make sure norm(xyz) >= 1
• If each number is out of range, the program will terminate

iii) delimiter

• Any number of spaces, horizontal tabs can be used between parameters
• If , is not used as an appropriate delimiter, the program will terminate
  • ex) R,G,B,, R,,G,B, etc...
• If an invalid number such as ++1, 0..001 is written, the program will terminate

iv) image

• Image files should be in P3 PPM format
• If image_path is "", it is determined that no image is used
  • For example, image "texture_path" "" when only texture_path is loaded, or not loading bumpmap
  • Specify a valid path for either texture or bumpmap
• If the specified path is not a valid ppm file, the program will terminate

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4. Example

• checkered corn, sphere and plane (rt_file/test_obj/multi_003.rt)
  

• image texture and bump mapped sphere (rt_file/simple_test/bump_1.rt)
  

• cornel box (rt_file/sample_perfect_ref_cornel_box.rt)
  

• sphere in the spotlight (rt_file/sample_spot_light.rt)
  

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5. Author

• ak0327
• molhot

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6. Confirmed Environments

• Ubuntu 22.04.2 LTS (ARM64)
• MacOS OS Ventura 13.0 (ARM64)

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7. Release

• 2023/Jun/18th

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8. References

• The Textbook of RayTracing @TDU
• C言語でレイトレーシングプログラムを作った
• 床井研究室 バンプマッピング
• Unity Documentation 法線マップ
• Ray Tracing in One Weekend
• Jamis Buck, The Ray Tracer Challenge, Pragmatic Bookshelf
• Fletcher Dunn, Ian Parberry, 実例で学ぶゲーム3D数学（松田 晃一, 訳）, オライリージャパン
• Eric Lengyel, ゲームプログラミングのための3Dグラフィックス数学（狩野 智英, 訳）, ボーンデジタル
• 村岡一信/千葉則茂, CによるCGレイトレーシング, サイエンス社