To reproduce, create a new go module with the contents of https://github.com/charmbracelet/harmonica/blob/master/examples/physics/main.go, run go mod tidy and run go build

I expected a binary to compile, but instead I received:

; go build                                                                                                                                                                                                             
# iamadrawist
./main.go:34:24: undefined: harmonica.Projectile
./main.go:35:23: undefined: harmonica.Point
./main.go:77:23: undefined: harmonica.Point
./main.go:78:23: undefined: harmonica.Vector
./main.go:79:23: undefined: harmonica.TerminalGravity
./main.go:81:25: undefined: harmonica.NewProjectile

I think this is because the harmonica github project's most recently published tagged version is 0.1, which does not contain these files.

This update generalizes the package from a spring-centric one to a general-purpose animation library with thanks to @maaslalani’s projectile motion contribution.

This is a tiny refactor that doesn't change any functionality.

While playing around with this library, I saw that waitASec sometimes sleeps for 500ms and 750ms, for me this makes sense to call it wait instead of waitASec and accept a time.Duration instead of an int.

Not a big deal either way though! Feel free to merge or close this PR.

Great work on this library! :D

Exposes Velocity and Acceleration of the Projectile.

This allows clients of harmonica projectiles to view the internal velocity and acceleration to perform calculations or checks based on these values.

Use case: https://github.com/maaslalani/confetty/pull/4

I was mostly able to port all of the code from https://github.com/maaslalani/confetty to use the harmonica physics code.

Using harmonica from confetty: https://github.com/maaslalani/confetty/pull/2

All I needed to change was returning a pointer to the projectile instead of the value from the NewProjectile function and everything worked.

This PR introduces 2D and 3D projectile motion to be used with Harmonica. It's fairly simple for now but usable with stuff like https://github.com/maaslalani/confetty

Example Usage:

projectile := NewProjectile(FPS(60), Point{6.0, 100.0, 0.0}, Vector{2.0, 0.0, 0.0}, Vector{2.0, -9.81, 0.0})

someUpdateLoop(func() {
  pos := projectile.Update()
})

NOTE, this is still missing:

1. Projectile mass
2. Forces (projectile.AddForce(Force{...})...))
3. Collisions (maybe?)

when attempted to run example provided at https://github.com/charmbracelet/harmonica/blob/master/examples/spring/opengl/main.go returns error as below. wondering if am missing to install any package ?

(base) ➜  temp go run main.go
# pkg-config --cflags  -- gl gl
Package gl was not found in the pkg-config search path.
Perhaps you should add the directory containing `gl.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gl' found
Package gl was not found in the pkg-config search path.
Perhaps you should add the directory containing `gl.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gl' found
pkg-config: exit status 1
# github.com/go-gl/glfw/v3.3/glfw
vendor/github.com/go-gl/glfw/v3.3/glfw/c_glfw.go:4:10: fatal error: glfw/src/context.c: No such file or directory
    4 | #include "glfw/src/context.c"
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.

Looks like a perfect match for gio.

https://github.com/gioui/gio-example

gio is a golang gui and from a brief look at your code it looks like a very good match for GIO,

gio gives the opportunity to update gui elements on each frame tick for example.