Rust3D

A basic 3D viewer written in Rust for rotating, zooming, and loading .obj files.

Features

• Rotate the 3D model.
• Zoom in and out.
• Load .obj files dynamically.

Controls

Key/Mouse	Action
Left Click + Drag	Rotate the model
Space	Toggle auto-rotation
B	Change background color
M	Change object color
Up / +	Zoom in
Down / -	Zoom out
L	Load a new .obj file
Escape	Exit the program

How It Works

demo.mp4

Rotation Matrices

The 3D point ((x, y, z)) is rotated using standard rotation matrices:

• X-axis Rotation:

$$\begin{cases} x' = x \\ y' = y \cos\theta - z \sin\theta \\ z' = y \sin\theta + z \cos\theta \end{cases}$$

• Perspective Projection:

$$\begin{cases} u = x \cdot \frac{\text{scale}}{z + \text{distance}} + \frac{\text{screen\_width}}{2} \\ v = -y \cdot \frac{\text{scale}}{z + \text{distance}} + \frac{\text{screen\_height}}{2} \end{cases}$$