Computer Graphics

Basic topics from Computer Graphics

1. Geometry description.
2. Displaying the model as polygons. The Algorithm Bresenham.
3. Animation creation, affine transformations.
4. Bezier curves.
5. Bezier clock.
6. Rendering 3D model. OpenGL.

Requirements

pip install -U -r requirements.txt

Obj format notation

Obj file - Utah Teapot model:

1. The list of vertices - "v" market
2. Facets - "f" market

The program finds: number of vertices and faces, max and min values of (x, y, z) and the surface area.

python main.py -p source/teapot.obj

Algorithm Bresenham

Drawing of the teapot using the algorithm Bresenham.

python main.py -p source/teapot.obj -s 1024 1024 -b 255 255 255 -c 0 0 255 --scale 145 --save True

Animation gif

Create rotation animations, zoom, and color changes. Affine transformation. Download ffmpeg.exe to create gif or mp4 animations. On the developer's website.

wget https://github.com/Vlad15lav/Computer-Graphics/releases/download/animation/ffmpeg.exe -O source/ffmpeg.exe

python main.py -f source/ffmpeg.exe -p source/teapot.obj -b 255 255 255 --frames 100 --fps 24 --interval 30

Bezier curves

Create an animation of changing digits (0-9) based on Bezier curves.

wget https://github.com/Vlad15lav/Computer-Graphics/releases/download/animation/ffmpeg.exe -O source/ffmpeg.exe

python main.py -f source/ffmpeg.exe -p source/digits.json -t 200 -u 24 -b 0 0 0 -c 0 255 0 --fps 24 --interval 30

Bezier clock

Creating the Bezier clock.

python main.py -p source/digits.json -b 0 0 0 -c 0 0 255 --bright 10 --zone 3

Rendering 3D model. OpenGL

Rendering 3D model, OpenGL annotation.

Reference Coordinates in 3D graphics:

• Local space
• World space
• View space
• Clip space
• Screen space

Culling of invisible faces

• Back-face culling
• Z-buffer

Texture overlay

• Texture coordinates (vt)
• Interpolation of barycentric coordinates

Lighting with the Phong reflection model

• Ambient, Diffuse, Specular
• Lighting attenuation

Rendering

• Wire model
• Model with faces (gray color)
• Model with textures
• Model with lighting
• Model with textures + lighting

Rendering help:

python main.py --help

usage: Computer Graphics: 3D Rendering - Vlad15lav [-h] [-m MODEL]
                                                   [-s LOAD_SCENE]
                                                   [-b BGCOLOR [BGCOLOR ...]]
                                                   [--wire] [--gray]
                                                   [--texture] [--light]
                                                   [--save] [--save_scene]

optional arguments:
  -h, --help            show this help message and exit
  -m MODEL, --model MODEL
                        path yml file
  -s LOAD_SCENE, --load_scene LOAD_SCENE
                        path scene file
  -b BGCOLOR [BGCOLOR ...], --bgcolor BGCOLOR [BGCOLOR ...]
                        background color
  --wire                wire model
  --gray                gray model by back-face culling
  --texture             texture enable
  --light               light enable
  --save                save img
  --save_scene          save scene

Rendering command:

python main.py -m african_head --texture --light --save

Creating scene:

Rendering the african head

python main.py -m african_head --texture --light --save_scene

Add the model's eyes

python main.py -m african_eyes --load_scene african_head --texture --light --save --save_scene

Creating an animation:

Rotate african head model

python rotate_model.py -m african_head -f source/ffmpeg.exe --texture --light

Rotate the light source

python rotate_light.py -m african_head -f source/ffmpeg.exe --texture --light