ddiakopoulos / tinygizmo

:triangular_ruler: An simple immediate-mode 3D gimzo/manipulator (translation, rotation, scale widget) in ~1200 LoC

tinygizmo

This project is a lightweight, self-contained library for gizmo editing commonly found in many game engines. It includes mechanisms for manipulating 3d position, rotation, and scale. Implemented in C++11, the library does not perform rendering directly and instead provides a per-frame buffer of world-space triangles.

An included example is built on top of GLFW (with an OpenGL 3.3 context). Known limitations include hardcoded assumptions about a right-handed, Y-up coordinate system. While the gizmos are provided with vertex normals, the example does not perform any fancy shading. Furthermore, mouse-drag input with certain gizmos at extreme interaction grazing angles is known to produce anomalous output.

Motivation

This project was born out of mild frustration with other immediate-mode gizmo libraries. Instead of 4x4 matrices and euler angles, the library exposes a rigid_transform consisting of a 3d position, rotation quaternion, and scale. The library is implemented in around 1200 lines of code, which also includes a complete 3d math library in ~400 LoC - linalg.h. Alternatives include ImGuizmo and Im3D. Tinygizmo fits in-between these projects by being fully self-contained (no dependency on Dear ImGui), and by being provided in the public domain.

Features

• Both axis-aligned global and object-local transform modes for translational and rotational gizmos
• Optional ability draw the gizmos with a constant screen-space scale
• Snap-to-unit (both linear and angular)
  • Set any of the snap_ values in the gizmo_application_state struct.
• VR ready (the user must call update(...) and draw() for each eye)
• Hotkeys for transitioning between translation, rotation, and scaling:
  • ctrl-t to activate the translation gizmo
  • ctrl-r to activate the rotation gizmo
  • ctrl-s to activate the scale gizmo
  • ctrl-l to toggle between global and local transform modes

Attribution

This project would not have been possible without reference implementations in the public-domain workbench project.

License

This is free and unencumbered software released into the public domain. For more information, please refer to http://unlicense.org

tinygizmo's Issues

rotation gizmo does not behave correctly with translations

Feature request: gizmo size independent of distance from camera

It would be useful to have an option (like the snapping ones) to get the gizmo scaled according to the distance from the camera so it remains with constant size on the screen no matter where it is in the world.

cool project! thanks for making it! It is a lot simpler than the 2 other immediate mode gizmos I was evaluating!

Also the readme should be updated - the snapping options are in gizmo_application_state and not in interaction_state

[feature request] gizmo usage events - start/stop

perhaps by querying some flag of the state after updating the context - this would be very useful for easier undo/redo of actions and would also make it much easier to determine if the input is being consumed by the gizmo or not.

add namespace to library

Imagine a suitable namespace and use it

scale gizmo should be drawn with local transform