Function3DAnimator

An Android app for building and animating user-defined 3D mathematical surfaces.

The project lets you enter functions, render them with OpenGL ES 2.0, and animate them over time when the formula depends on t. It is a personal project intended to become a polished open-source portfolio piece and a future F-Droid candidate.

What it does

• Plots one or more 3D surfaces on the same scene
• Supports time-dependent functions and live animation
• Supports multiple function definition modes:
  • z(x, y)
  • z(r, phi)
  • r(theta, phi)
  • parametric surfaces x(u, v), y(u, v), z(u, v)
• Includes built-in example scenes such as waves, a pulsating sphere, a cylinder, and a Moebius strip
• Stores user-defined functions locally with Room
• Provides a custom math keyboard for entering expressions more easily
• Lets the user control rendering options such as grid visibility, rotation sensitivity, and graph screen orientation

Architecture

Function3DAnimator is built around a custom expression parser and evaluator that turns user-entered math into renderable surface data, then generates OpenGL ES 2.0 vertex and normal buffers for Cartesian, elliptical, spherical, and parametric surfaces. The rendering layer supports time-dependent formulas through the t variable, so surfaces can be animated without changing the stored function definition, while Room persistence keeps user functions and built-in examples available offline. The UI combines the original Android Views flow with an ongoing Kotlin/Jetpack Compose migration, making the project a compact example of math parsing, real-time 3D rendering, local data storage, and incremental Android modernization.

Example expressions

Non-parametric:

x*x*cos(t)/3.0
exp(-(x^2+y^2)*(4+cos(t)))
sin(r+phi+t)
1+cos(t)

Parametric:

x(u,v) = (1+0.5*v*cos(0.5*(u+t)))*cos(u+t)
y(u,v) = (1+0.5*v*cos(0.5*u+t))*sin(u+t)
z(u,v) = 0.5*v*sin(0.5*(u+t))

Supported math

Operators:

• +
• -
• *
• /
• ^

Functions:

• sqrt
• exp
• sin
• cos
• tg
• ctg
• abs
• log
• ln
• asin
• acos
• atg
• sh
• ch

Variables depend on the selected function type:

• Cartesian: x, y, t
• Elliptical: r, phi, t
• Spherical: theta, phi, t
• Parametric: u, v, t

Tech stack

• Kotlin
• Android Views + Jetpack Compose
• OpenGL ES 2.0
• Room
• Hilt
• Gradle Kotlin DSL

Current Android configuration:

• minSdk = 26
• targetSdk = 36
• Java/Kotlin target: 17

Build and run

Requirements

• Android Studio with a recent Android SDK installed
• JDK 17
• An Android device or emulator with OpenGL ES 2.0 support

From Android Studio

1. Open the project in Android Studio.
2. Let Gradle sync.
3. Run the app configuration on a device or emulator.

From the command line

.\gradlew.bat assembleDebug

To run unit tests:

.\gradlew.bat testDebugUnitTest

Project structure

• app/src/main/java/io/github/nvlad1/function3danimator/model contains the function models, surface generation, and expression evaluation logic
• app/src/main/java/io/github/nvlad1/function3danimator/openGLutils contains the renderer and OpenGL helpers
• app/src/main/java/io/github/nvlad1/function3danimator/database contains local persistence with Room
• app/src/main/java/io/github/nvlad1/function3danimator/ui contains the app screens and UI logic

Status

This is an actively maintained personal project. The app is fully functional and continues to be improved, with ongoing refinements and documentation updates.

The app allows Android system backups. No data is transmitted by the app itself, but system-level backup services (e.g., Google Drive) may store app data externally.

Author

Vladislav Naboka

License

This project is licensed under the MIT License - see the LICENSE file for details.